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Sample records for digital constant fraction

  1. FPGA implementation of digital constant fraction algorithm with fractional delay for optimal time resolution

    Energy Technology Data Exchange (ETDEWEB)

    Jaeger, Markus, E-mail: jaeger@informatik.uni-leipzig.de [Faculty of Mathematics and Computer Science, University of Leipzig, PF 100920, 04009 Leipzig (Germany); Butz, Tilman, E-mail: butz@physik.uni-leipzig.de [Faculty of Physics and Earth Sciences, University of Leipzig, Linnestr. 5, 04103 Leipzig (Germany)

    2012-05-11

    In a recent development of a fully digital spectrometer for time differential perturbed angular correlations a true constant fraction trigger (CFT) algorithm was implemented that, however, allowed for integer delays, i.e. integer multiples of the sampling interval, only. With a sampling rate of 1 GS/s and BaF{sub 2} scintillators this turned out to be insufficient. Here, we present an extension of the algorithm to fractional delays implemented in field programmable gate arrays (FPGAs). Furthermore, we derive a criterion for the delay for optimum timing based on the steepest slope of the CFT signal. Experimental data are given for LaBr{sub 3}(Ce) scintillators and 511 keV-511 keV prompt coincidences that corroborate the theoretical result.

  2. Analysis of time resolution in a dual head LSO+PSPMT PET system using low pass filter interpolation and digital constant fraction discriminator techniques

    Energy Technology Data Exchange (ETDEWEB)

    Monzo, Jose M. [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)], E-mail: jmonfer@aaa.upv.es; Lerche, Christoph W.; Martinez, Jorge D.; Esteve, Raul; Toledo, Jose; Gadea, Rafael; Colom, Ricardo J.; Herrero, Vicente; Ferrando, Nestor; Aliaga, Ramon J.; Mateo, Fernando [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Sanchez, Filomeno [Nuclear Medical Physics Group, IFIC Institute, Consejo Superior de Investigaciones Cientificas (CSIC), 46980 Paterna (Spain); Mora, Francisco J. [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); Benlloch, Jose M. [Nuclear Medical Physics Group, IFIC Institute, Consejo Superior de Investigaciones Cientificas (CSIC), 46980 Paterna (Spain); Sebastia, Angel [Digital Systems Design (DSD) Group, ITACA Institute, Universidad Politecnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain)

    2009-06-01

    PET systems need good time resolution to improve the true event rate, random event rejection, and pile-up rejection. In this study we propose a digital procedure for this task using a low pass filter interpolation plus a Digital Constant Fraction Discriminator (DCFD). We analyzed the best way to implement this algorithm on our dual head PET system and how varying the quality of the acquired signal and electronic noise analytically affects timing resolution. Our detector uses two continuous LSO crystals with a position sensitive PMT. Six signals per detector are acquired using an analog electronics front-end and these signals are processed using an in-house digital acquisition board. The test bench developed simulates the electronics and digital algorithms using Matlab. Results show that electronic noise and other undesired effects have a significant effect on the timing resolution of the system. Interpolated DCFD gives better results than non-interpolated DCFD. In high noise environments, differences are reduced. An optimum delay selection, based on the environment noise, improves time resolution.

  3. Fractional constant elasticity of variance model

    OpenAIRE

    Ngai Hang Chan; Chi Tim Ng

    2007-01-01

    This paper develops a European option pricing formula for fractional market models. Although there exist option pricing results for a fractional Black-Scholes model, they are established without accounting for stochastic volatility. In this paper, a fractional version of the Constant Elasticity of Variance (CEV) model is developed. European option pricing formula similar to that of the classical CEV model is obtained and a volatility skew pattern is revealed.

  4. On a continued fraction expansion for Euler's constant

    CERN Document Server

    Pilehrood, Khodabakhsh Hessami

    2010-01-01

    Recently, A.~I.~Aptekarev and his collaborators found a sequence of rational approximations to Euler's constant $\\gamma$ defined by a third-order homogeneous linear recurrence. In this paper, we give a new interpretation of Aptekarev's approximations to $\\gamma$ in terms of Meijer $G$-functions and hypergeometric-type series. This approach allows us to describe a very general construction giving linear forms in $1$ and $\\gamma$ with rational coefficients. Using this construction we find new rational approximations to $\\gamma$ generated by a second-order inhomogeneous linear recurrence with polynomial coefficients. This leads to a continued fraction (though not a simple continued fraction) for Euler's constant. It seems to be the first non-trivial continued fraction expansion convergent to Euler's constant sub-exponentially, the elements of which can be expressed as a general pattern. It is interesting to note that the same homogeneous recurrence generates a continued fraction for the Euler-Gompertz constant f...

  5. ON SOLUTIONS TO SINGULAR FRACTIONAL DIFFERENTIAL SYSTEMS WITH CONSTANT COEFFICIENTS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper, we consider solutions to singular fractional differential systems with constant coefficients involving Riemann-Liouville differential operator. At first, we study the solvability of the systems. Then we discuss the general solution to the system.

  6. A high-linearity digital-to-time converter technique: constant-slope charging

    NARCIS (Netherlands)

    Ru, Jiayoon Zhiyu; Palattella, Claudia; Geraedts, Paul; Klumperink, Eric; Nauta, Bram

    2015-01-01

    A digital-to-time converter (DTC) controls time delay by a digital code, which is useful, for example, in a sampling oscilloscope, fractional-N PLL, or time-interleaved ADC. This paper proposes constant-slope charging as a method to realize a DTC with intrinsically better integral non-linearity (INL

  7. Charge to digital converter with constant resolution over the dynamic range

    Energy Technology Data Exchange (ETDEWEB)

    Nascetti, A. [Department of Aerospace and Astronautics Engineering, Sapienza University of Rome, via Eudossiana 16, 00184, Rome (Italy)

    2009-12-15

    A novel pixel-level charge to digital converter circuit suitable for multi-channel charge sensitive amplifiers or pixelated readout ICs for hybrid detectors is presented. The proposed circuit features large dynamic range operation with constant relative resolution over the whole dynamic range. These characteristics have been obtained by introducing the fractional charge packet counting concept. In particular, a solution has been proposed to obtain the analog-to-digital conversion with constant number of significant bits.

  8. Fractional crystallization of iron meteorites: Constant versus changing partition coefficients

    Science.gov (United States)

    Jones, J. H.

    1994-01-01

    Analyses of magmatic iron meteorites, plotted on LogC(sub i) vs LogC(sub Ni) diagrams, often form linear arrays. Traditionally, this linearity has been ascribed to fractional crystallization under the assumption of constant partition coefficients (i.e., Rayleigh fractionation). Paradoxically, however, partition coefficients in the Fe-Ni-S-P system are decidedly not constant. This contribution provides a rationale for understanding how trends on LogC(sub i) vs LogC(sub Ni) diagrams can be linear, even when partition coefficients are changing rapidly.

  9. Transform of Riccati equation of constant coefficients through fractional procedure

    CERN Document Server

    Rosu, H C; Socorro, J

    2003-01-01

    We use a particular fractional generalization of the ordinary differential equations that we apply to the Riccati equation of constant coefficients. By this means the latter is transformed into a modified Riccati equation with the free term expressed as a power of the independent variable which is of the same order as the order of the applied fractional derivative. We provide the solutions of the modified equation and employ the results for the case of the cosmological Riccati equation of FRW barotropic cosmologies that has been recently introduced by Faraoni.

  10. Transform of Riccati equation of constant coefficients through fractional procedure

    Energy Technology Data Exchange (ETDEWEB)

    Rosu, H C [Department of Applied Mathematics, IPICyT, Apdo Postal 3-74 Tangamanga, San Luis Potosi (Mexico); Madueno, A L [Instituto de Fisica, Universidad de Guanajuato, Apdo Postal E-143, Leon (Mexico); Socorro, J [Instituto de Fisica, Universidad de Guanajuato, Apdo Postal E-143, Leon (Mexico)

    2003-01-31

    We use a particular fractional generalization of the ordinary differential equations that we apply to the Riccati equation of constant coefficients. By this means the latter is transformed into a modified Riccati equation with the free term expressed as a power of the independent variable which is of the same order as the order of the applied fractional derivative. We provide the solutions of the modified equation and employ the results for the case of the cosmological Riccati equation of FRW barotropic cosmologies that has been recently introduced by Faraoni.

  11. Derivation of the fine structure constant using fractional dynamics

    CERN Document Server

    Goldfain, E

    2003-01-01

    Both classical and quantum electrodynamics assume that random fluctuations are absent from the steady-state evolution of the underlying physical system. Our work goes beyond this approximation and accounts for the continuous exposure to stochastic fluctuations. It is known that the asymptotic limit of quantum field dynamics, dominated by large and persistent perturbations, may be described as an anomalous diffusion process. We use fractional calculus as an appropriate tool to handle this highly non-trivial regime. It is shown that the fine structure constant can be recovered from the fractional evolution equation of the density matrix under standard normalization conditions.

  12. High Resolution Photon Timing with MCP-PMTs: A Comparison of a Commercial Constant Fraction Discriminator (CFD) with the ASIC-based Waveform Digitizers TARGET and WaveCatcher

    Energy Technology Data Exchange (ETDEWEB)

    Breton, D.; /Orsay, LAL; Delagnes, E.; /DAPNIA, Saclay; Maalmi, J.; /Orsay, LAL; Nishimura, K.; Ruckman, L.L.; Varner, G.; /Hawaii U.; Va' vra, J.; /SLAC

    2011-07-14

    There is a considerable interest to develop new time-of-flight detectors using, for example, micro-channel-plate photodetectors (MCP-PMTs). The question we pose in this paper is if new waveform digitizer ASICs, such as the WaveCatcher and TARGET, operating with a sampling rate of 2-3 GSa/s can compete with 1GHz BW CFD/TDC/ADC electronics. We have performed a series of measurements with these waveform digitizers coupled to MCP-PMTs operating at low gain and with a signal equivalent to {approx}40 photoelectrons. The tests were done with a laser diode on detectors operating under the same condition used previously in SLAC and Fermilab beam tests. Our test results indicate that one can achieve similar resolution with both methods. Although the commercial CFD-based electronics does exist and performs very well, it is difficult to implement on a very large scale, and therefore the custom electronics is needed. In addition, the analog delay line requirement makes it very difficult to incorporate CFD discriminators in ASIC designs.

  13. Discretization of Fractional Differential Equations by a Piecewise Constant Approximation

    CERN Document Server

    Angstmann, Christopher N; McGann, Anna V

    2016-01-01

    There has recently been considerable interest in using a nonstandard piecewise approximation to formulate fractional order differential equations as difference equations that describe the same dynamical behaviour and are more amenable to a dynamical systems analysis. Unfortunately, due to mistakes in the fundamental papers, the difference equations formulated through this process do not capture the dynamics of the fractional order equations. We show that the correct application of this nonstandard piecewise approximation leads to a one parameter family of fractional order differential equations that converges to the original equation as the parameter tends to zero. A closed formed solution exists for each member of this family and leads to the formulation of a difference equation that is of increasing order as time steps are taken. Whilst this does not lead to a simplified dynamical analysis it does lead to a numerical method for solving the fractional order differential equation. The method is shown to be eq...

  14. INITIAL VALUE PROBLEM FOR FRACTIONAL ORDER EQUATION WITH CONSTANT COEFFICIENTS

    Directory of Open Access Journals (Sweden)

    Bogatyreva F. T.

    2016-12-01

    Full Text Available In this paper we construct an explicit representation of the solution of the Cauchy problem for ordinary differential equation of fractional order with Dzhrbashyan-Nersesyan operators.

  15. A Digitally Programmable Differential Integrator with Enlarged Time Constant

    Directory of Open Access Journals (Sweden)

    S. K. Debroy

    1994-12-01

    Full Text Available A new Operational Amplifier (OA-RC integrator network is described. The novelties of the design are used of single grounded capacitor, ideal integration function realization with dual-input capability and design flexibility for extremely large time constant involving an enlargement factor (K using product of resistor ratios. The aspect of the digital control of K through a programmable resistor array (PRA controlled by a microprocessor has also been implemented. The effect of the OA-poles has been analyzed which indicates degradation of the integrator-Q at higher frequencies. An appropriate Q-compensation design scheme exhibiting 1 : |A|2 order of Q-improvement has been proposed with supporting experimental observations.

  16. The inner regions of disk galaxies: a constant baryonic fraction?

    CERN Document Server

    Lelli, Federico

    2014-01-01

    For disk galaxies (spirals and irregulars), the inner circular-velocity gradient (inner steepness of the rotation curve) correlates with the central surface brightness with a slope of ~0.5. This implies that the central dynamical mass density scales almost linearly with the central baryonic density. Here I show that this empirical relation is consistent with a simple model where the central baryonic fraction f_bar(0) is fixed to 1 (no dark matter) and the observed scatter is due to differences in the baryonic mass-to-light ratio M_bar/L (ranging from 1 to 3 in the R-band) and in the characteristic thickness of the central stellar component dz (ranging from 100 to 500 pc). Models with lower baryonic fractions are possible, although they require some fine-tuning in the values of M_bar/L and dz. Regardless of the actual value of f_bar(0), the fact that different types of galaxies do not show strong variations in f_bar(0) is surprising, and may represent a challenge for models of galaxy formation in a LCDM cosmol...

  17. The Inner Regions of Disk Galaxies: A Constant Baryonic Fraction?

    Directory of Open Access Journals (Sweden)

    Federico Lelli

    2014-07-01

    Full Text Available For disk galaxies (spirals and irregulars, the inner circular-velocity gradient dRV0 (inner steepness of the rotation curve correlates with the central surface brightness ∑*,0 with a slope of ~0.5. This implies that the central dynamical mass density scales almost linearly with the central baryonic density. Here I show that this empirical relation is consistent with a simple model where the central baryonic fraction ƒbar,0 is fixed to 1 (no dark matter and the observed scatter is due to differences in the baryonic mass-to-light ratio Mbar / LR (ranging from 1 to 3 in the R-band and in the characteristic thickness of the central stellar component Δz (ranging from 100 to 500 pc. Models with lower baryonic fractions are possible, although they require some fine-tuning in the values of Mbar/LR and Δz. Regardless of the actual value of ƒbar,0, the fact that different types of galaxies do not show strong variations in ƒbar,0 is surprising, and may represent a challenge for models of galaxy formation in a Λ Cold Dark Matter (ΛCDM cosmology.

  18. Tailoring automatic exposure control toward constant detectability in digital mammography

    Energy Technology Data Exchange (ETDEWEB)

    Salvagnini, Elena, E-mail: elena.salvagnini@uzleuven.be [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Bosmans, Hilde [Department of Imaging and Pathology, Medical Physics and Quality Assessment, KUL, Herestraat 49, Leuven B-3000, Belgium and Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium); Struelens, Lara [SCK-CEN, Boeretang 200, Mol 2400 (Belgium); Marshall, Nicholas W. [Department of Radiology, UZ Gasthuisberg, Herestraat 49, Leuven B-3000 (Belgium)

    2015-07-15

    Purpose: The automatic exposure control (AEC) modes of most full field digital mammography (FFDM) systems are set up to hold pixel value (PV) constant as breast thickness changes. This paper proposes an alternative AEC mode, set up to maintain some minimum detectability level, with the ultimate goal of improving object detectability at larger breast thicknesses. Methods: The default “OPDOSE” AEC mode of a Siemens MAMMOMAT Inspiration FFDM system was assessed using poly(methyl methacrylate) (PMMA) of thickness 20, 30, 40, 50, 60, and 70 mm to find the tube voltage and anode/filter combination programmed for each thickness; these beam quality settings were used for the modified AEC mode. Detectability index (d′), in terms of a non-prewhitened model observer with eye filter, was then calculated as a function of tube current-time product (mAs) for each thickness. A modified AEC could then be designed in which detectability never fell below some minimum setting for any thickness in the operating range. In this study, the value was chosen such that the system met the achievable threshold gold thickness (T{sub t}) in the European guidelines for the 0.1 mm diameter disc (i.e., T{sub t} ≤ 1.10 μm gold). The default and modified AEC modes were compared in terms of contrast-detail performance (T{sub t}), calculated detectability (d′), signal-difference-to-noise ratio (SDNR), and mean glandular dose (MGD). The influence of a structured background on object detectability for both AEC modes was examined using a CIRS BR3D phantom. Computer-based CDMAM reading was used for the homogeneous case, while the images with the BR3D background were scored by human observers. Results: The default OPDOSE AEC mode maintained PV constant as PMMA thickness increased, leading to a reduction in SDNR for the homogeneous background 39% and d′ 37% in going from 20 to 70 mm; introduction of the structured BR3D plate changed these figures to 22% (SDNR) and 6% (d′), respectively

  19. Digital implementation of fractional order PID controller and its application

    Institute of Scientific and Technical Information of China (English)

    Wang Zhenbin; Wang Zhenlei; Cao Guangyi; Zhu Xinjian

    2005-01-01

    A new discretization scheme is proposed for the design of a fractional order PID controller. In the design of a fractional order controller the interest is mainly focused on the s-domain, but there exists a difficult problem in the s-domain that needs to be solved, i.e. how to calculate fractional derivatives and integrals efficiently and quickly. Our scheme adopts the time domain that is well suited for Z-transform analysis and digital implementation. The main idea of the scheme is based on the definition of Grunwald-Letnicov fractional calculus. In this case some limited terms of the definition are taken so that it is much easier and faster to calculate fractional derivatives and integrals in the time domain or zdomain without loss much of the precision. Its effectiveness is illustrated by discretization of half-order fractional differential and integral operators compared with that of the analytical scheme. An example of designing fractional order digital controllers is included for illustration, in which different fractional order PID controllers are designed for the control of a nonlinear dynamic system containing one of the four different kinds of nonlinear blocks: saturation, deadzone, hysteresis, and relay.

  20. Fractional Fourier Transform Applied to Digital Images Encryption

    Science.gov (United States)

    Vilardy, Juan M.; Torres, Cesar O.; Mattos, Lorenzo

    2008-04-01

    In the present paper a digital algorithm was developed to make phase encryption of digital indexed images to color using the fractional Fourier transform (the images in RGB are converted to indexed before to encrypt). The indexed images are represented by a matrix of M×N pixels (where M defines the height and N is the Width of the image) and a color map (it's a matrix of C×3 elements, where C indicates the colors number of the image and the number 3 indicates the three columns associated with the color components: Red, Green and Blue of each pixel of the matrix of M×N) associated to the matrix of pixels to suitably represent the color information of the image. The indexed image (matrix of M×N pixels) to encrypt is placed as the phase of a complex exponential, then is transformed three times and multiplied in intermediate steps by two random phase masks statistically independent thus to obtain the encrypted image, for decrypt the coding image the encryption procedure is applied in the inverse sense to the conjugated complex of the encrypted image, then is taken the negative of the phase of the resulting function of the decryption process and the original image is obtained this way that had been encrypted; For the color map equal procedure is applied in the encryption/decryption process described previously for the matrix of M×N pixels. In the implemented cryptographic algorithm five keys are used, constituted by three fractional orders and two random phase masks, all these keys are necessary for a correct decryption providing a dependability to the transference of images by means of the communications nets.

  1. Delayed neutron fraction and prompt decay constant measurement in the MINERVE reactor using the PSI instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Perret, Gregory [Paul Scherrer Institute, Villigen, 5232, (Switzerland)

    2015-07-01

    The critical decay constant (B/A), delayed neutron fraction (B) and generation time (A) of the Minerve reactor were measured by the Paul Scherrer Institut (PSI) and the Commissariat a l'Energie Atomique (CEA) in September 2014 using the Feynman-alpha and Power Spectral Density neutron noise measurement techniques. Three slightly subcritical configuration were measured using two 1-g {sup 235}U fission chambers. This paper reports on the results obtained by PSI in the near critical configuration (-2g). The most reliable and precise results were obtained with the Cross-Power Spectral Density technique: B = 708.4±9.2 pcm, B/A = 79.0±0.6 s{sup -1} and A 89.7±1.4 micros. Predictions of the same kinetic parameters were obtained with MCNP5-v1.6 and the JEFF-3.1 and ENDF/B-VII.1 nuclear data libraries. On average the predictions for B and B/A overestimate the experimental results by 5% and 11%, respectively. The discrepancy is suspected to come from either a corruption of the data or from the inadequacy of the point kinetic equations to interpret the measurements in the Minerve driven system. (authors)

  2. A constant loop bandwidth fractional-N frequency synthesizer for GNSS receivers

    Institute of Scientific and Technical Information of China (English)

    Yin Xizhen; Xiao Shimao; Jin Yuhua; Wu Qiwu; Ma Chengyan; Ye Tianchun

    2012-01-01

    A constant loop bandwidth fractional-N frequency synthesizer for portable civilian global navigation satellite system (GNSS) receivers implemented in a 130 nm 1P6M CMOS process is introduced.Via discrete working regions,the LC-VCO obtains a wide tuning range with a simple structure and small VCO gain.Spur suppression technology is proposed to minimize the phase offset introduced by PFD and charge pumps.The optimized bandwidth is maintained by an auto loop calibration module to adjust the charge pump current when the PLL output frequency changes or the temperature varies.Measurement results show that this synthesizer attains an in-band phase noise lower than -93 dBc at a 10 kHz offset and a spur less than -70 dBc; the bandwidth varies by ± 3% for all the GNSS signals.The whole synthesizer consumes 4.5 mA current from a 1 V supply,and its area (without the LO tested buffer) is 0.5 mm2.

  3. Constant fan-in digital neural networks are VLSI-optimal

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.

    1995-12-31

    The paper presents a theoretical proof revealing an intrinsic limitation of digital VLSI technology: its inability to cope with highly connected structures (e.g. neural networks). We are in fact able to prove that efficient digital VLSI implementations (known as VLSI-optimal when minimizing the AT{sup 2} complexity measure - A being the area of the chip, and T the delay for propagating the inputs to the outputs) of neural networks are achieved for small-constant fan-in gates. This result builds on quite recent ones dealing with a very close estimate of the area of neural networks when implemented by threshold gates, but it is also valid for classical Boolean gates. Limitations and open questions are presented in the conclusions.

  4. Fractional Order Digital Differentiator Design Based on Power Function and Least squares

    Science.gov (United States)

    Kumar, Manjeet; Rawat, Tarun Kumar

    2016-10-01

    In this article, we propose the use of power function and least squares method for designing of a fractional order digital differentiator. The input signal is transformed into a power function by using Taylor series expansion, and its fractional derivative is computed using the Grunwald-Letnikov (G-L) definition. Next, the fractional order digital differentiator is modelled as a finite impulse response (FIR) system that yields fractional order derivative of the G-L type for a power function. The FIR system coefficients are obtained by using the least squares method. Two examples are used to demonstrate that the fractional derivative of the digital signals is computed by using the proposed technique. The results of the third and fourth examples reveal that the proposed technique gives superior performance in comparison with the existing techniques.

  5. Analytic solutions of Oldroyd-B fluid with fractional derivatives in a circular duct that applies a constant couple

    Directory of Open Access Journals (Sweden)

    M.B. Riaz

    2016-12-01

    Full Text Available The aim of this article was to analyze the rotational flow of an Oldroyd-B fluid with fractional derivatives, induced by an infinite circular cylinder that applies a constant couple to the fluid. Such kind of problem in the settings of fractional derivatives has not been found in the literature. The solutions are based on an important remark regarding the governing equation for the non-trivial shear stress. The solutions that have been obtained satisfy all imposed initial and boundary conditions and can easily be reduced to the similar solutions corresponding to ordinary Oldroyd-B, fractional/ordinary Maxwell, fractional/ordinary second-grade, and Newtonian fluids performing the same motion. The obtained results are expressed in terms of Newtonian and non-Newtonian contributions. Finally, the influence of fractional parameters on the velocity, shear stress and a comparison between generalized and ordinary fluids is graphically underlined.

  6. Three-dimensional simulations of microstructural evolution in polycrystalline dual-phase materials with constant volume fractions

    DEFF Research Database (Denmark)

    Poulsen, Stefan Othmar; Voorhees, P.W.; Lauridsen, Erik Mejdal

    2013-01-01

    The microstructural evolution of a polycrystalline dual-phase material with a constant volume fraction of the phases was investigated using large-scale three-dimensional phase-field simulations. All materials parameters are taken to be isotropic, and microstructures with volume fractions of 50....../50 and 40/60 were examined. After an initial transient, the number of grains decrease from ∼2600 to ∼500. It was found that the mean grain size of grains of both phases obeyed a power law with an exponent of 3, and the microstructural evolution was found to be controlled by diffusion. Steady...... with the topology of single-phase grain structures as determined by experiment and simulation. The evolution of size and number of faces for the minority and majority phase grains in the 40/60 volume fraction simulation is presented and discussed. Non-constant curvature across some interphase boundaries...

  7. Comparison of digital holographic interferometry and constant temperature anemometry for measurement of temperature field in fluid

    Science.gov (United States)

    Doleček, Roman; Psota, Pavel; Lédl, Vít.; Vít, Tomáś; Dančová, Petra; Kopecký, Václav

    2015-05-01

    The presented paper shows possibility of using digital holographic interferometry (DHI) for temperature field measurement in moving fluids. This method uses a modified Twymann-Green setup having double sensitivity instead of commonly used Mach-Zehnder type of interferometer in order to obtain sufficient phases change of the field. On the other hand this setup is not light efficient as Mach-Zehnder interferometer. For measurement of the fast periodical phenomenon is not necessary to use always the high speed camera. One can consider this field to coherent phenomenon. With employing one digital camera synchronized to periodic field and external triggered one can capture whole period of the phenomenon. However the projections form one viewing direction of asymmetrical temperature field maybe misguided. Hence for sufficient examination of the asymmetrical field one should capture a large number of the phenomenon's projections from different viewing directions. This projections are later used for 3D tomographic reconstruction of the whole temperature field and its time evolution. One of the commonly used method for temperature field measurement in moving fluids is hot wire method - constant temperature anemometry (CTA). In contrast to whole field measurement of DHI it is an invasive point temperature measurement method. One of the limiting factor of using CTA in moving fluids is frequency of temperature changes. This changes should not exceed 1 kHz. This limitation could be overcome by using of optical methods such as DHI. The results of temperature field measurement achieved by both method are compared in the paper.

  8. A novel algorithm for fractional resizing of digital image in DCT domain

    Institute of Scientific and Technical Information of China (English)

    Wang Ci; Zhang Wenjun; Zheng Meng

    2005-01-01

    Fractional resizing of digital images is needed in various applications, such as displaying at different resolution depending on that of display device, building image index for an image database, and changing resolution according to the transmission channel bandwidth. With the wide use of JPEG and MPEG, almost all digital images are stored and transferred in DCT compressed format. Inorder to save the computation and memory cost, it is desirable to do resizing in DCT domain directly. This paper presents a fast and efficient method, which possesses the capability of fractional resizing in DCT domain. Experimental results confirm that this scheme can achieve significant computation cost reduction while maintain better quality.

  9. Research on Cellular Instabilities of Lean Premixed Syngas Flames under Various Hydrogen Fractions Using a Constant Volume Vessel

    Directory of Open Access Journals (Sweden)

    Hong-Meng Li

    2014-07-01

    Full Text Available An experimental study of the intrinsic instabilities of H2/CO lean (φ = 0.4 to φ = 1.0 premixed flames at different hydrogen fractions ranging from 0% to 100% at elevated pressure and room temperature was performed in a constant volume vessel using a Schlieren system. The unstretched laminar burning velocities were compared with data from the previous literature and simulated results. The results indicate that excellent agreements are obtained. The cellular instabilities of syngas-air flames were discussed and critical flame radii were measured. When hydrogen fractions are above 50%, the flame tends to be more stable as the equivalence ratio increases; however, the instability increases for flames of lower hydrogen fractions. For the premixed syngas flame with hydrogen fractions greater than 50%, the decline in cellular instabilities induced by the increase in equivalence ratio can be attributed to a reduction of diffusive-thermal instabilities rather than increased hydrodynamic instabilities. For premixed syngas flames with hydrogen fractions lower than 50%, as the equivalence ratio increases, the cellular instabilities become more evident because the enhanced hydrodynamic instabilities become the dominant effect. For premixed syngas flames, the enhancement of cellular instabilities induced by the increase in hydrogen fraction is the result of both increasing diffusive-thermal and hydrodynamic instabilities.

  10. The Initial Value Problem for Fractional Order Differential Equations with Constant Coefficients. 2nd Edition

    Science.gov (United States)

    1989-09-30

    The Theory of Linear Operators, The Principia Press (1936). 13. W. Guttinger, "Generalized Functions and Dispersion Relations in Physics...Monagine," Acta Mathematica , Vol 29 (1905), pg 101. 17, K. B. Oldham and J. Spanier, The Fractional Calculus, Academic Press, Orlando, (1974). 18. Y. N

  11. Digital watermarking for still image based on discrete fractional fourier transform

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents a digital watermarking technique based on discrete fractional Fourier transform(DFRFT), discusses the transformation of the original image by DFRFT, and the modification of DFRFT coefficients of the original image by the information of watermark, and concludes from experimental results that the proposed tech nique is robust to lossy compression attack.

  12. On the accurate estimation of gap fraction during daytime with digital cover photography

    Science.gov (United States)

    Hwang, Y. R.; Ryu, Y.; Kimm, H.; Macfarlane, C.; Lang, M.; Sonnentag, O.

    2015-12-01

    Digital cover photography (DCP) has emerged as an indirect method to obtain gap fraction accurately. Thus far, however, the intervention of subjectivity, such as determining the camera relative exposure value (REV) and threshold in the histogram, hindered computing accurate gap fraction. Here we propose a novel method that enables us to measure gap fraction accurately during daytime under various sky conditions by DCP. The novel method computes gap fraction using a single DCP unsaturated raw image which is corrected for scattering effects by canopies and a reconstructed sky image from the raw format image. To test the sensitivity of the novel method derived gap fraction to diverse REVs, solar zenith angles and canopy structures, we took photos in one hour interval between sunrise to midday under dense and sparse canopies with REV 0 to -5. The novel method showed little variation of gap fraction across different REVs in both dense and spares canopies across diverse range of solar zenith angles. The perforated panel experiment, which was used to test the accuracy of the estimated gap fraction, confirmed that the novel method resulted in the accurate and consistent gap fractions across different hole sizes, gap fractions and solar zenith angles. These findings highlight that the novel method opens new opportunities to estimate gap fraction accurately during daytime from sparse to dense canopies, which will be useful in monitoring LAI precisely and validating satellite remote sensing LAI products efficiently.

  13. Measurement of the Ds l(+)ve branching fractions and the decay constant fDs+

    NARCIS (Netherlands)

    Ablikim, M.; Achasov, M. N.; Ai, X. C.; Albayrak, O.; Albrecht, M.; Ambrose, D. J.; Amoroso, A.; An, F. F.; An, Q.; Bai, J. Z.; Bakina, O.; Ferroli, R. Baldini; Ban, Y.; Bennett, D. W.; Bennett, J. V.; Bertani, M.; Bettoni, D.; Bian, J. M.; Bianchi, F.; Boger, E.; Boyko, I.; Briere, R. A.; Cai, H.; Cai, X.; Cakir, O.; Calcaterra, A.; Cao, G. F.; Cetin, S. A.; Chang, J. F.; Chelkov, G.; Chen, G.; Chen, H. S.; Chen, H. Y.; Chen, J. C.; Chen, M. L.; Chen, S.; Chen, S. J.; Chen, X.; Chen, X. R.; Chen, Y. B.; Cheng, H. P.; Chu, X. K.; Cibinetto, G.; Dai, H. L.; Dai, J. P.; Dbeyssi, A.; Dedovich, D.; Deng, Z. Y.; Denig, A.; Denysenko, I.; Destefanis, M.; De Mori, F.; Ding, Y.; Dong, C.; Dong, J.; Dong, L. Y.; Dong, M. Y.; Dou, Z. L.; Du, S. X.; Duan, P. F.; Fan, J. Z.; Fang, J.; Fang, S. S.; Fang, X.; Fang, Y.; Farinelli, R.; Fava, L.; Feldbauer, F.; Felici, G.; Feng, C. Q.; Fioravanti, E.; Fritsch, M.; Fu, C. D.; Gao, Q.; Gao, X. L.; Gao, X. Y.; Gao, Y.; Gao, Z.; Garzia, I.; Goetzen, K.; Gong, L.; Gong, W. X.; Gradl, W.; Greco, M.; Gu, M. H.; Gu, Y. T.; Guan, Y. H.; Guo, A. Q.; Guo, L. B.; Guo, R. P.; Guo, Y.; Guo, Y. P.; Haddadi, Z.; Hafner, A.; Han, S.; Hao, X. Q.; Harris, F. A.; He, K. L.; Held, T.; Heng, Y. K.; Hou, Z. L.; Hu, C.; Hu, H. M.; Hu, J. F.; Hu, T.; Hu, Y.; Huang, G. S.; Huang, J. S.; Huang, X. T.; Huang, X. Z.; Huang, Y.; Huang, Z. L.; Hussain, T.; Andersson, W. Ikegami; Ji, Q.; Ji, Q. P.; Ji, X. B.; Ji, X. L.; Jiang, L. W.; Jiang, X. S.; Jiang, X. Y.; Jiao, J. B.; Jiao, Z.; Jin, D. P.; Jin, S.; Johansson, T.; Julin, A.; Kalantar-Nayestanaki, N.; Kang, X. L.; Kang, X. S.; Kavatsyuk, M.; Ke, B. C.; Kiese, P.; Kliemt, R.; Kloss, B.; Kolcu, O. B.; Kopf, B.; Kornicer, M.; Kupsc, A.; Koehn, W.; Lange, J. S.; Lara, M.; Larin, P.; Leng, C.; Li, C.; Li, Cheng; Li, D. M.; Li, F.; Li, F. Y.; Li, G.; Li, H. B.; Li, H. J.; Li, J. C.; Li, Jin; Li, K.; Li, K.; Li, Lei; Li, P. R.; Li, Q. Y.; Li, T.; Li, W. D.; Li, W. G.; Li, X. L.; Li, X. N.; Li, X. Q.; Li, Y. B.; Li, Z. B.; Liang, H.; Liang, Y. F.; Liang, Y. T.; Liao, G. R.; Lin, D. X.; Liu, B.; Liu, B. J.; Liu, C. X.; Liu, D.; Liu, F. H.; Liu, Fang; Liu, Feng; Liu, H. B.; Liu, H. H.; Liu, H. H.; Liu, H. M.; Liu, J.; Liu, J. B.; Liu, J. P.; Liu, J. Y.; Liu, K.; Liu, K. Y.; Liu, L. D.; Liu, P. L.; Liu, Q.; Liu, S. B.; Liu, X.; Liu, Y. B.; Liu, Z. A.; Liu, Zhiqing; Loehner, H.; Lou, X. C.; Lu, H. J.; Lu, J. G.; Lu, Y.; Lu, Y. P.; Luo, C. L.; Luo, M. X.; Luo, T.; Luo, X. L.; Lyu, X. R.; Ma, F. C.; Ma, H. L.; Ma, L. L.; Ma, M. M.; Ma, Q. M.; Ma, T.; Ma, X. N.; Ma, X. Y.; Ma, Y. M.; Maas, F. E.; Maggiora, M.; Mao, Y. J.; Mao, Z. P.; Marcello, S.; Messchendorp, J. G.; Min, J.; Min, T. J.; Mitchell, R. E.; Mo, X. H.; Mo, Y. J.; Morales, C. Morales; Muchnoi, N. Yu.; Muramatsu, H.; Nefedov, Y.; Nerling, F.; Nikolaev, I. B.; Ning, Z.; Nisar, S.; Niu, S. L.; Niu, X. Y.; Olsen, S. L.; Ouyang, Q.; Pacetti, S.; Pan, Y.; Patteri, P.; Pelizaeus, M.; Peng, H. P.; Peters, K.; Pettersson, J.; Ping, J. L.; Ping, R. G.; Poling, R.; Prasad, V.; Qi, H. R.; Qi, M.; Qian, S.; Qiao, C. F.; Qin, L. Q.; Qin, N.; Qin, X. S.; Qin, Z. H.; Qiu, J. F.; Rashid, K. H.; Redmer, C. F.; Ripka, M.; Rong, G.; Rosner, Ch.; Ruan, X. D.; Sarantsev, A.; Savrie, M.; Schoenning, K.; Schumann, S.; Shan, W.; Shao, M.; Shen, C. P.; Shen, P. X.; Shen, X. Y.; Sheng, H. Y.; Shi, M.; Song, W. M.; Song, X. Y.; Sosio, S.; Spataro, S.; Sun, G. X.; Sun, J. F.; Sun, S. S.; Sun, X. H.; Sun, Y. J.; Sun, Y. Z.; Sun, Z. J.; Sun, Z. T.; Tang, C. J.; Tang, X.; Tapan, I.; Thorndike, E. H.; Tiemens, M.; Ullrich, M.; Uman, I.; Varner, G. S.; Wang, B.; Wang, B. L.; Wang, D.; Wang, Y.; Wang, K.; Wang, L. L.; Wang, L. S.; Wang, M.; Wang, P.; Wang, P. L.; Wang, W.; Wang, W. P.; Wang, X. F.; Wang, Y.; Wang, Y. D.; Wang, Y. F.; Wang, Y. Q.; Wang, Z.; Wang, Z. G.; Wang, Z. H.; Wang, Z. Y.; Wang, Z. Y.; Weber, T.; Wei, D. H.; Weidenkaff, P.; Wen, S. P.; Wiedner, U.; Wolke, M.; Wu, L. H.; Wu, L. J.; Wu, Z.; Xia, L.; Xia, L. G.; Xia, Y.; Xiao, D.; Xiao, H.; Xiao, Z. J.; Xie, Y. G.; Xiu, Q. L.; Xu, G. F.; Xu, J. J.; Xu, L.; Xu, Q. J.; Xu, Q. N.; Xu, X. P.; Yan, L.; Yan, W. B.; Yan, W. C.; Yan, Y. H.; Yang, H. J.; Yang, H. X.; Yang, L.; Yang, Y. X.; Ye, M.; Ye, M. H.; Yin, J. H.; Yu, B. X.; Yu, C. X.; Yu, J. S.; Yuan, C. Z.; Yuan, W. L.; Yuan, Y.; Yuncu, A.; Zafar, A. A.; Zallo, A.; Zeng, Y.; Zeng, Z.; Zhang, B. X.; Zhang, B. Y.; Zhang, C.; Zhang, C. C.; Zhang, D. H.; Zhang, H. H.; Zhang, H. Y.; Zhang, J.; Zhang, J. J.; Zhang, J. L.; Zhang, J. Q.; Zhang, J. W.; Zhang, J. Y.; Zhang, J. Z.; Zhang, K.; Zhang, L.; Zhang, S. Q.; Zhang, X. Y.; Zhang, Y.; Zhang, Y. H.; Zhang, Y. N.; Zhang, Y. T.; Zhang, Yu; Zhang, Z. H.; Zhang, Z. P.; Zhang, Z. Y.; Zhao, G.; Zhao, J. W.; Zhao, J. Y.; Zhao, J. Z.; Zhao, Lei; Zhao, Ling; Zhao, M. G.; Zhao, Q.; Zhao, Q. W.; Zhao, S. J.; Zhao, T. C.; Zhao, Y. B.; Zhao, Z. G.; Zhemchugov, A.; Zheng, B.; Zheng, J. P.; Zheng, W. J.; Zheng, Y. H.; Zhong, B.; Zhou, L.; Zhou, X.; Zhou, X. K.; Zhou, X. R.; Zhou, X. Y.; Zhu, K.; Zhu, K. J.; Zhu, S.; Zhu, S. H.; Zhu, X. L.; Zhu, Y. C.; Zhu, Y. S.; Zhu, Z. A.; Zhuang, J.; Zotti, L.; Zou, B. S.; Zou, J. H.

    2016-01-01

    Using 482 pb(-1) of e(+) e(-) collision data collected at a center-of-mass energy of root s = 4.009 GeV with the BESIII detector, we measure the branching fractions of the decays D-s(+) -> u(+)v(u) and D-s(+) -> tau(+)v(tau). By constraining the ratio of decay rates of Ds(+) to tau(+)v(u) and to u(+

  14. a digital lego a digital lego-based learning environment for fraction ...

    African Journals Online (AJOL)

    eobe

    1, 2 DEPARTMENT OF COMPUTER SCIENCE, FEDERAL UNIVERSITY OF ... taken the form of creative act and application of game ... levels of learning is the step-by-step solution to ... learning fractions, which include developing an.

  15. Rate Constant and Branching Fraction for the NH2 + NO2 Reaction

    DEFF Research Database (Denmark)

    Klippenstein, Stephen J.; Harding, Lawrence B.; Glarborg, Peter

    2013-01-01

    The NH2 + NO2 reaction has been studied experimentally and theoretically. On the basis of laser photolysis/LIF experiments, the total rate constant was determined over the temperature range 295–625 K as k1,exp(T) = 9.5 × 10–7(T/K)−2.05 exp(−404 K/T) cm3 molecule–1 s–1. This value is in the upper...... may facilitate a small flux between the adducts. High- and low-pressure limit rate coefficients for the various product channels of NH2 + NO2 are determined from the ab initio TST-based master equation calculations for the temperature range 300–2000 K. The theoretical predictions are in good agreement...

  16. Design of a Constant Fraction Discriminator for the VFAT3 front-end ASIC of the CMS GEM detector

    CERN Document Server

    AUTHOR|(CDS)2069646; Abbas, M.; Abbrescia, M.; Abdelalim, A.A.; Abi Akl, M.; Aboamer, O.; Acosta, D.; Ahmad, A.; Ahmed, W.; Ahmed, W.; Aleksandrov, A.; Aly, R.; Altieri, P.; Asawatangtrakuldee, C.; Aspell, P.; Assran, Y.; Awan, I.; Bally, S.; Ban, Y.; Banerjee, S.; Barashko, V.; Barria, P.; Bencze, G.; Beni, N.; Benussi, L.; Bhopatkar, V.; Bianco, S.; Bos, J.; Bouhali, O.; Braghieri, A.; Braibant, S.; Buontempo, S.; Calabria, C.; Caponero, M.; Caputo, C.; Cassese, F.; Castaneda, A.; Cauwenbergh, S.; Cavallo, F.R.; Celik, A.; Choi, M.; Choi, S.; Christiansen, J.; Cimmino, A.; Colafranceschi, S.; Colaleo, A.; Conde Garcia, A.; Czellar, S.; Dabrowski, M.M.; De Lentdecker, G.; De Oliveira, R.; de Robertis, G.; Dildick, S.; Dorney, B.; Elmetenawee, W.; Endroczi, G.; Errico, F.; Fenyvesi, A.; Ferry, S.; Furic, I.; Giacomelli, P.; Gilmore, J.; Golovtsov, V.; Guiducci, L.; Guilloux, F.; Gutierrez, A.; Hadjiiska, R.M.; Hassan, A.; Hauser, J.; Hoepfner, K.; Hohlmann, M.; Hoorani, H.; Iaydjiev, P.; Jeng, Y.G.; Kamon, T.; Karchin, P.; Korytov, A.; Krutelyov, S.; Kumar, A.; Kim, H.; Lee, J.; Lenzi, T.; Litov, L.; Madorsky, A.; Maerschalk, T.; Maggi, M.; Magnani, A.; Mal, P.K.; Mandal, K.; Marchioro, A.; Marinov, A.; Masod, R.; Majumdar, N.; Merlin, J.A.; Mitselmakher, G.; Mohanty, A.K.; Mohamed, S.; Mohapatra, A.; Molnar, J.; Muhammad, S.; Mukhopadhyay, S.; Naimuddin, M.; Nuzzo, S.; Oliveri, E.; Pant, L.M.; Paolucci, P.; Park, I.; Passeggio,G.; Pavlov, B.; Philipps, B.; Piccolo, D.; Postema, H.; Puig Baranac, A.; Radi, A.; Radogna, R.; Raffone, G.; Ranieri, A.; Rashevski, G.; Riccardi, C.; Rodozov, M.; Rodrigues, A.; Ropelewski, L.; RoyChowdhury, S.; Ryu, G.; Ryu, M.S.; Safonov, A.; Salva, S.; Saviano, G.; Sharma, A.; Sharma, A.; Sharma, R.; Shah, A.H.; Shopova, M.; Sturdy, J.; Sultanov, G.; Swain, S.K.; Szillasi, Z.; Talvitie, J.; Tamma, C.; Tatarinov, A.; Tuuva, T.; Tytgat, M.; Vai, I.; Van Stenis, M.; Venditti, R.; Verhagen, E.; Verwilligen, P.; Vitulo, P.; Volkov, S.; Vorobyev, A.; Wang, D.; Wang, M.; Yang, U.; Yang, Y.; Yonamine, R.; Zaganidis, N.; Zenoni, F.; Zhang, A.

    2016-01-01

    In this work the design of a Constant Fraction Discriminator (CFD) to be used in the VFAT3 chip, currently under design for the read-out of the Triple-Gem detectors of the CMS experiment, is described. Simulations show that it is possible to extend the front-end shaping time in order to fully integrate the GEM detector signal charge whilst maintaining optimal timing resolution using the CFD technique. A prototype chip containing 8 CFDs was implemented in 130 nm CMOS technology to prove the effectiveness of the proposed architecture before its integration in the VFAT3 chip. The CFD design and test results will be shown.

  17. Net primary production of forests: a constant fraction of gross primary production?

    Science.gov (United States)

    Waring, R. H.; Landsberg, J. J.; Williams, M.

    1998-02-01

    Considerable progress has been made in our ability to model and measure annual gross primary production (GPP) by terrestrial vegetation. But challenges remain in estimating maintenance respiration (R(m)) and net primary production (NPP). To search for possible common relationships, we assembled annual carbon budgets from six evergreen and one deciduous forest in Oregon, USA, three pine plantations in New South Wales, Australia, a deciduous forest in Massachusetts, USA, and a Nothofagus forest on the South Island of New Zealand. At all 12 sites, a standard procedure was followed to estimate annual NPP of foliage, branches, stems, and roots, the carbon expended in synthesis of these organs (R(g)), their R(m), and that of previously produced foliage and sapwood in boles, branches, and large roots. In the survey, total NPP ranged from 120 to 1660 g C m(-2) year(-1), whereas the calculated fraction allocated to roots varied from 0.22 to 0.63. Comparative analysis indicated that the total NPP/GPP ratio was conservative (0.47 +/- 0.04 SD). This finding supports the possibility of greatly simplifying forest growth models. The constancy of the NPP/GPP ratio also provides an incentive to renew efforts to understand the environmental factors affecting partitioning of NPP above and belowground.

  18. Mittag-Leffler stability of fractional-order neural networks in the presence of generalized piecewise constant arguments.

    Science.gov (United States)

    Wu, Ailong; Liu, Ling; Huang, Tingwen; Zeng, Zhigang

    2017-01-01

    Neurodynamic system is an emerging research field. To understand the essential motivational representations of neural activity, neurodynamics is an important question in cognitive system research. This paper is to investigate Mittag-Leffler stability of a class of fractional-order neural networks in the presence of generalized piecewise constant arguments. To identify neural types of computational principles in mathematical and computational analysis, the existence and uniqueness of the solution of neurodynamic system is the first prerequisite. We prove that the existence and uniqueness of the solution of the network holds when some conditions are satisfied. In addition, self-active neurodynamic system demands stable internal dynamical states (equilibria). The main emphasis will be then on several sufficient conditions to guarantee a unique equilibrium point. Furthermore, to provide deeper explanations of neurodynamic process, Mittag-Leffler stability is studied in detail. The established results are based on the theories of fractional differential equation and differential equation with generalized piecewise constant arguments. The derived criteria improve and extend the existing related results.

  19. Measurements of branching fractions of leptonic and hadronic Ds+ meson decays and extraction of the Ds+ meson decay constant

    CERN Document Server

    Zupanc, A; Aihara, H; Arinstein, K; Asner, D M; Aushev, T; Bakich, A M; Bala, A; Bhuyan, B; Bonvicini, G; Bozek, A; Bračko, M; Brodzicka, J; Browder, T E; Chang, M -C; Chang, P; Chekelian, V; Chen, A; Chen, P; Cheon, B G; Chilikin, K; Chistov, R; Cho, K; Chobanova, V; Choi, S -K; Choi, Y; Cinabro, D; Dalseno, J; Danilov, M; Doležal, Z; Drásal, Z; Dutta, D; Eidelman, S; Farhat, H; Fast, J E; Ferber, T; Gaur, V; Gabyshev, N; Ganguly, S; Gillard, R; Goh, Y M; Golob, B; Haba, J; Hara, T; Hayasaka, K; Hayashii, H; Horii, Y; Hoshi, Y; Hou, W -S; Hsiung, Y B; Hyun, H J; Iijima, T; Inami, K; Ishikawa, A; Itoh, R; Iwasaki, Y; Iwashita, T; Jaegle, I; Julius, T; Kato, E; Kawai, H; Kawasaki, T; Kichimi, H; Kiesling, C; Kim, D Y; Kim, H O; Kim, J B; Kim, J H; Kim, M J; Kim, Y J; Kinoshita, K; Klucar, J; Ko, B R; Kodyš, P; Korpar, S; Križan, P; Krokovny, P; Kronenbitter, B; Kuhr, T; Kumita, T; Kuzmin, A; Kwon, Y -J; Lange, J S; Lee, S -H; Li, J; Libby, J; Liu, Z Q; Liventsev, D; Lukin, P; Miyata, H; Mizuk, R; Mohanty, G B; Moll, A; Mussa, R; Nakano, E; Nakao, M; Nedelkovska, E; Nisar, N K; Nishida, S; Nitoh, O; Ogawa, S; Okuno, S; Pakhlova, G; Park, C W; Park, H; Park, H K; Pedlar, T K; Pestotnik, R; Petrič, M; Piilonen, L E; Prim, M; Ritter, M; Röhrken, M; Rostomyan, A; Ryu, S; Sahoo, H; Saito, T; Sakai, Y; Sandilya, S; Santelj, L; Sanuki, T; Sato, Y; Savinov, V; Schneider, O; Schnell, G; Schwanda, C; Schwartz, A J; Semmler, D; Senyo, K; Sevior, M E; Shapkin, M; Shen, C P; Shibata, T -A; Shiu, J -G; Shwartz, B; Sibidanov, A; Simon, F; Sohn, Y -S; Sokolov, A; Solovieva, E; Starič, M; Steder, M; Sumiyoshi, T; Tamponi, U; Tanida, K; Tatishvili, G; Teramoto, Y; Trabelsi, K; Tsuboyama, T; Uchida, M; Uglov, T; Uno, S; Usov, Y; Vahsen, S E; Van Hulse, C; Vanhoefer, P; Varner, G; Vinokurova, A; Vorobyev, V; Wagner, M N; Wang, C H; Wang, M -Z; Wang, P; Wang, X L; Watanabe, M; Watanabe, Y; Won, E; Yamashita, Y; Yashchenko, S; Zhang, Z P; Zhilich, V; Zhulanov, V

    2013-01-01

    We present measurements of absolute branching fractions of hadronic and leptonic Ds+ decays to K- K+ pi+, anti-K0 K+, eta pi+, mu+ nu_mu and tau+ nu_tau and report a search for the leptonic Ds+ to e+ nu_e decays. The results are obtained from a large data sample collected at or near the Y(4S) and Y(5S) resonances with the Belle detector at the KEKB asymmetric-energy e+e- collider. The branching fractions of hadronic decays are measured to be Br(Ds+ -> K- K+ pi+) = (5.06 +- 0.15 +- 0.21)%, Br(Ds+ -> anti-K0 K+) = (2.95 +- 0.11 +- 0.09)%, and Br(Ds+ -> eta pi+) = (1.82 +- 0.14 +- 0.07)%, where the first and second uncertainties are statistical and systematic, respectively. The branching fractions of leptonic decays are measured to be Br(Ds+ -> mu+ nu_mu) = (0.531 +- 0.028 +- 0.020)%, and Br(Ds+ -> tau+ nu_tau) = (5.70 +- 0.21 +0.31-0.30)%, which are combined to determine the Ds+ meson decay constant f_Ds = (255.5 +- 4.2 +- 5.1) MeV. We find no significant signal for Ds+ -> e+ nu_e decays and set an upper limit ...

  20. Design of minimum multiplier fractional order differentiator based on lattice wave digital filter.

    Science.gov (United States)

    Barsainya, Richa; Rawat, Tarun Kumar; Kumar, Manjeet

    2017-01-01

    In this paper, a novel design of fractional order differentiator (FOD) based on lattice wave digital filter (LWDF) is proposed which requires minimum number of multiplier for its structural realization. Firstly, the FOD design problem is formulated as an optimization problem using the transfer function of lattice wave digital filter. Then, three optimization algorithms, namely, genetic algorithm (GA), particle swarm optimization (PSO) and cuckoo search algorithm (CSA) are applied to determine the optimal LWDF coefficients. The realization of FOD using LWD structure increases the design accuracy, as only N number of coefficients are to be optimized for Nth order FOD. Finally, two design examples of 3rd and 5th order lattice wave digital fractional order differentiator (LWDFOD) are demonstrated to justify the design accuracy. The performance analysis of the proposed design is carried out based on magnitude response, absolute magnitude error (dB), root mean square (RMS) magnitude error, arithmetic complexity, convergence profile and computation time. Simulation results are attained to show the comparison of the proposed LWDFOD with the published works and it is observed that an improvement of 29% is obtained in the proposed design. The proposed LWDFOD approximates the ideal FOD and surpasses the existing ones reasonably well in mid and high frequency range, thereby making the proposed LWDFOD a promising technique for the design of digital FODs. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  1. Determination of the accuracy and operating constants in a digitally biased ring core magnetometer

    Science.gov (United States)

    Green, A.W.

    1990-01-01

    By using a very stable voltage reference and a high precision digital-to-analog converter to set bias in digital increments, the inherently high stability and accuracy of a ring core magnetometer can be significantly enhanced. In this case it becomes possible to measure not only variations about the bias level, but to measure the entire value of the field along each magnetometer sensing axis in a nearly absolute sense. To accomplish this, one must accurately determine the value of the digital bias increment for each axis, the zero field offset value for each axis, the scale values, and the transfer coefficients (or nonorthogonality angles) for pairs of axes. This determination can be carried out very simply, using only the Earth's field, a proton magnetometer, and a tripod-mounted fixture which is capable of rotations about two axes that are mutually perpendicular to the Earth's magnetic field vector. ?? 1990.

  2. Variations in clast morphology for different till fractions: implementation of digital imagery

    Science.gov (United States)

    Dominiczak, Aleksander

    2014-05-01

    The form of clastic particles provides information about debris history including abrasion and transportation which are vital to geomorphological research because of its usefulness for differentiating subglacial debris form englacialy, supraglacialy and fluvially transported sediments, and for understanding subglacial processes. There are numerous attempts to clastic particles form assessment, both qualitative and quantitative and advance in technology enables the use of digital imaging and image processing in order to calculate the precise indicators of shape and roundness (small-scale surface features superimposed on shape and roundness are not a subject of this study). Computer calculations are fast, reliable and objective and its use decrease probability of errors. They are applicable to till deposits analysis and may help in understanding the processes of glacial deposition. Till deposits consist of a mixture of various fractions of sediment, where coarser and thinner grains are together activated, entrained in ice, transported, deposited and post-depositional transformed together in the same time and conditions. That implies similarity of processes acting on the particles, but not necessarily theirs effects. Physical properties of grain are of great significance for its vulnerability to acting forces. An important feature of the tills is grain size, which has a high volatility in a sample. The hypothesis of this issue suggests it is possible that different fractions of till sediment have significantly different form characteristics. Verification of the thesis is important because standardly only one fraction is selected to analysis and to draw conclusions from. Main objective is to test differences in clast morphology for different till fraction. In order to answer the research problem, the author has examined samples from a contemporary glaciated region, Nordenskiöld glacier foreland in central Spitsbergen. During the field work samples were collected from

  3. Design of an automated multicapillary instrument with fraction collection for DNA mutation discovery by constant denaturant capillary electrophoresis (CDCE).

    Science.gov (United States)

    Li, Qingbo; Deka, Chiranjit; Glassner, Brian J; Arnold, Kevin; Li-Sucholeiki, Xiao-Cheng; Tomita-Mitchell, Aoy; Thilly, William G; Karger, Barry L

    2005-08-01

    A fundamental goal ingenomics is the discovery of genetic variation that contributes to disease states or to differential drug responses. Single nucleotide polymorphism (SNP) detection has been the focus of much attention in the study of genetic variation over the last decade. These SNPs typically occur at a frequency greater than 1% in the human genome. Recently, low-frequency alleles are also being increasingly recognized as critical to obtain an improved understanding of the correlation between genetic variation and disease. Although many methods have been reported for the discovery and scoringof SNPs, sensitive, automated, and cost-effective methods and platforms for the discovery of low-frequency alleles are not yet readily available. We describe here an automated multicapillary instrument for high-throughput detection of low-frequency alleles from pooled samples using constant denaturant capillary electrophoresis. The instrument features high optical sensitivity (1 x 10(-12) M fluorescein detection limit), precise and stable temperature control (+/- 0.01degrees C), and automation for sample delivery, injection, matrix replacement, and fraction collection. The capillary array is divided into six groups of four capillaries, each of which can be independently set at any temperature ranging from room temperature to 90 degrees C. The key performance characteristics of the instrument are reported.

  4. Enhanced time response of 1-in. LaBr{sub 3}(Ce) crystals by leading edge and constant fraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Vedia, V., E-mail: mv.vedia@ucm.es [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); Mach, H. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); National Centre for Nuclear Research, Division for Nuclear Physics, BP1, PL-00-681 Warsaw (Poland); Fraile, L.M.; Udías, J.M. [Grupo de Física Nuclear, Facultad de CC. Físicas, Universidad Complutense, CEI Moncloa, ES-28040 Madrid (Spain); Lalkovski, S. [Faculty of Physics, University of Sofia, St. Kliment Ohridski, BG-1164 Sofia (Bulgaria)

    2015-09-21

    We have characterized in depth the time response of three detectors equipped with cylindrical LaBr{sub 3}(Ce) crystals with dimensions of 1-in. in height and 1-in. in diameter, and having nominal Ce doping concentration of 5%, 8% and 10%. Measurements were performed at {sup 60}Co and {sup 22}Na γ-ray energies against a fast BaF{sub 2} reference detector. The time resolution was optimized by the choice of the photomultiplier bias voltage and the fine tuning of the parameters of the constant fraction discriminator, namely the zero-crossing and the external delay. We report here on the optimal time resolution of the three crystals. It is observed that timing properties are influenced by the amount of Ce doping and the crystal homogeneity. For the crystal with 8% of Ce doping the use of the ORTEC 935 CFD at very shorts delays in addition to the Hamamatsu R9779 PMT has made it possible to improve the LaBr{sub 3}(Ce) time resolution from the best literature value at {sup 60}Co photon energies to below 100 ps.

  5. Online rate control in digital cameras for near-constant distortion based on minimum/maximum criterion

    Science.gov (United States)

    Lee, Sang-Yong; Ortega, Antonio

    2000-04-01

    We address the problem of online rate control in digital cameras, where the goal is to achieve near-constant distortion for each image. Digital cameras usually have a pre-determined number of images that can be stored for the given memory size and require limited time delay and constant quality for each image. Due to time delay restrictions, each image should be stored before the next image is received. Therefore, we need to define an online rate control that is based on the amount of memory used by previously stored images, the current image, and the estimated rate of future images. In this paper, we propose an algorithm for online rate control, in which an adaptive reference, a 'buffer-like' constraint, and a minimax criterion (as a distortion metric to achieve near-constant quality) are used. The adaptive reference is used to estimate future images and the 'buffer-like' constraint is required to keep enough memory for future images. We show that using our algorithm to select online bit allocation for each image in a randomly given set of images provides near constant quality. Also, we show that our result is near optimal when a minimax criterion is used, i.e., it achieves a performance close to that obtained by applying an off-line rate control that assumes exact knowledge of the images. Suboptimal behavior is only observed in situations where the distribution of images is not truly random (e.g., if most of the 'complex' images are captured at the end of the sequence.) Finally, we propose a T- step delay rate control algorithm and using the result of 1- step delay rate control algorithm, we show that this algorithm removes the suboptimal behavior.

  6. Fractional M-band dual tree complex wavelet transform for digital watermarking

    Indian Academy of Sciences (India)

    Harpal Singh; Lakhwinder Kaur; Kulbir Singh

    2014-04-01

    In this paper, a novel digital watermarking scheme using fractional M-band dual tree complex wavelet transform (Fr-M-band-DT-CWT) is proposed. High frequency channels have wide bandwidth and low frequency channels have narrow bandwidth. These characteristics are suitable for analysing low frequency signal, but not for relatively high frequency signal. The images often contain many edges, which may cause rich middle and high frequency components in the 2-band wavelet domain. Therefore, the ordinary 2-band dual tree complex wavelet transform (DTCWT) is not well-suited for analysing the image. So, the M-band DT-CWT with the FrFT called Fr-M-band-DT-CWT is proposed in this paper to address this problem. Further, we integrate the Fr-M-band-DT-CWT with singular value decomposition (SVD) in order to enhance the performance. Experimental results of the proposed watermarking scheme are compared with the previously available watermarking algorithms, fractional Fourier transform (FrFT), fractional wavelet transform (FrWT). Further, the proposed watermark extraction scheme is also tested on different attacks. The results of the present investigations show that the proposed watermarking scheme is superior as compared to other existing watermarking schemes.

  7. Estimation of Fractional Vegetation Cover Based on Digital Camera Survey Data and a Remote Sensing Model

    Institute of Scientific and Technical Information of China (English)

    HU Zhen-qi; HE Fen-qin; YIN Jian-zhong; LU Xia; TANG Shi-lu; WANG Lin-lin; LI Xiao-jing

    2007-01-01

    The objective of this paper is to improve the monitoring speed and precision of fractional vegetation cover (fc). It mainly focuses onfc estimation when fcmax andfcmin are not approximately equal to 100% and 0%, respectively due to using remote sensing image with medium or low spatial resolution. Meanwhile, we present a new method offc estimation based on a random set offc maximum and minimum values from digital camera (DC) survey data and a dimidiate pixel model. The results show that this is a convenient, efficient and accurate method forfc monitoring, with the maximum error -0.172 and correlation coefficient of 0.974 between DC survey data and the estimated value of the remote sensing model. The remaining DC survey data can be used as verification data for the precision of thefc estimation. In general, the estimation offc based on DC survey data and a remote sensing model is a brand-new development trend and deserves further extensive utilization.

  8. A 56.4-to-63.4 GHz Multi-Rate All-Digital Fractional-N PLL for FMCW Radar Applications in 65 nm CMOS

    NARCIS (Netherlands)

    Wu, W.; Staszewski, R.B.; Long, J.R.

    2014-01-01

    A mm-wave digital transmitter based on a 60 GHz all-digital phase-locked loop (ADPLL) with wideband frequency modulation (FM) for FMCW radar applications is proposed. The fractional-N ADPLL employs a high-resolution 60 GHz digitally controlled oscillator (DCO) and is capable of multi-rate two-point

  9. Different elution modes and field programming in gravitational field-flow fractionation. IV. Field programming achieved with channels of non-constant cross-sections.

    Science.gov (United States)

    Plocková, Jana; Matulík, Frantisek; Chmelík, Josef

    2002-04-26

    Force field programming provided increased speed of separation with an improved resolution and detection capability in many field-flow fractionation (FFF) techniques. Gravitational field-flow fractionation (GFFF) uses the Earth's gravitational field to cause the settlement of particles towards the channel accumulation wall. Although this field is constant and relatively weak, there are different ways to implement force field programming in GFFF. Because hydrodynamic lift forces (HLF) participate in the separation process in focusing (hyperlayer) elution mode, they can control the resulting force field acting on particles via changes in flow-velocity. These changes can be accomplished by a programmable pump or with channels of non-constant cross-sections. This work is focused on flow-velocity programming accomplished with channels of non-constant cross-sections. Three trapezoidal channels of decreasing breadth and two channels of decreasing height (along the longitudinal axis) are tested as tools for optimization of the separation of a model silica gel particle mixture. The trapezoidal channels yielded reduced separation times. However, taking into account both speed of separation and resolution, the optimization effect was lower compared with the flow-rate gradients generated by a programmable pump. The channels of non-constant height did not yield advantageous separations.

  10. Short-range test of the universality of gravitational constant G at the millimeter scale using a digital image sensor

    Science.gov (United States)

    Ninomiya, K.; Akiyama, T.; Hata, M.; Hatori, M.; Iguri, T.; Ikeda, Y.; Inaba, S.; Kawamura, H.; Kishi, R.; Murakami, H.; Nakaya, Y.; Nishio, H.; Ogawa, N.; Onishi, J.; Saiba, S.; Sakuta, T.; Tanaka, S.; Tanuma, R.; Totsuka, Y.; Tsutsui, R.; Watanabe, K.; Murata, J.

    2017-09-01

    The composition dependence of gravitational constant G is measured at the millimeter scale to test the weak equivalence principle, which may be violated at short range through new Yukawa interactions such as the dilaton exchange force. A torsion balance on a turning table with two identical tungsten targets surrounded by two different attractor materials (copper and aluminum) is used to measure gravitational torque by means of digital measurements of a position sensor. Values of the ratios \\tilde{G}_Al-W/\\tilde{G}_Cu-W -1 and \\tilde{G}_Cu-W/GN -1 were (0.9 +/- 1.1sta +/- 4.8sys) × 10-2 and (0.2 +/- 0.9sta +/- 2.1sys) × 10-2 , respectively; these were obtained at a center to center separation of 1.7 cm and surface to surface separation of 4.5 mm between target and attractor, which is consistent with the universality of G. A weak equivalence principle (WEP) violation parameter of η_Al-Cu(r∼ 1 cm)=(0.9 +/- 1.1sta +/- 4.9sys) × 10-2 at the shortest range of around 1 cm was also obtained.

  11. Chaos Generated from the Fractional-Order Complex Chen System and its Application to Digital Secure Communication

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan

    2013-04-01

    In this paper, a novel dynamic system, the fractional-order complex Chen system, is presented for the first time. Dynamic behaviors of system are studied analytically and numerically. Different routes to chaos are shown, and diverse kinds of motions are identified and exhibited by means of bifurcation diagram, portrait phase and the largest Lyapunov exponent. Secondly, an application to digital secure communication based on the novel system is proposed, in which security is enhanced by continually switching different orders of derivative in an irregular pattern. Furthermore, making full use of the advantage of high-capacity transmission of complex system, the improved digital secure communication scheme is achieved based on hybrid synchronization in coupled fractional-order complex Chen system, that means anti-synchronization in real part of state variables and projective synchronization in imaginary part, respectively. The corresponding numerical simulations demonstrate the effectiveness and feasibility of the proposed schemes.

  12. A non-linear preprocessing for opto-digital image encryption using multiple-parameter discrete fractional Fourier transform

    Science.gov (United States)

    Azoug, Seif Eddine; Bouguezel, Saad

    2016-01-01

    In this paper, a novel opto-digital image encryption technique is proposed by introducing a new non-linear preprocessing and using the multiple-parameter discrete fractional Fourier transform (MPDFrFT). The non-linear preprocessing is performed digitally on the input image in the spatial domain using a piecewise linear chaotic map (PLCM) coupled with the bitwise exclusive OR (XOR). The resulting image is multiplied by a random phase mask before applying the MPDFrFT to whiten the image. Then, a chaotic permutation is performed on the output of the MPDFrFT using another PLCM different from the one used in the spatial domain. Finally, another MPDFrFT is applied to obtain the encrypted image. The parameters of the PLCMs together with the multiple fractional orders of the MPDFrFTs constitute the secret key for the proposed cryptosystem. Computer simulation results and security analysis are presented to show the robustness of the proposed opto-digital image encryption technique and the great importance of the new non-linear preprocessing introduced to enhance the security of the cryptosystem and overcome the problem of linearity encountered in the existing permutation-based opto-digital image encryption schemes.

  13. Increasing the accuracy and automation of fractional vegetation cover estimation from digital photographs

    Science.gov (United States)

    The use of automated methods to estimate canopy cover (CC) from digital photographs has increased in recent years given its potential to produce accurate, fast and inexpensive CC measurements. Wide acceptance has been delayed because of the limitations of these methods. This work introduces a novel ...

  14. Fractionation of oil sands-process affected water using pH-dependent extractions: a study of dissociation constants for naphthenic acids species.

    Science.gov (United States)

    Huang, Rongfu; Sun, Nian; Chelme-Ayala, Pamela; McPhedran, Kerry N; Changalov, Mohamed; Gamal El-Din, Mohamed

    2015-05-01

    The fractionation of oil sands process-affected water (OSPW) via pH-dependent extractions was performed to quantitatively investigate naphthenic acids (NAs, CnH2n+ZO2) and oxidized NAs (Ox-NAs) species (CnH2n+ZO3 and CnH2n+ZO4) using ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS). A mathematical model was also developed to estimate the dissociation constant pKa for NAs species, considering the liquid-liquid extraction process and the aqueous layer acid-base equilibrium. This model provides estimated dissociation constants for compounds in water samples based on fractionation extraction and relative quantification. Overall, the sum of O2-, O3-, and O4-NAs species accounted for 33.6% of total extracted organic matter. Accumulative extracted masses at different pHs revealed that every oxygen atom added to NAs increases the pKa (i.e., O2-NAs

  15. Measurement of the Branching Fraction for D8+ rarr tau+nu_tau and Extraction of the Decay Constant f_D_s

    Energy Technology Data Exchange (ETDEWEB)

    Lees, J.P.; Poireau, V.; Prencipe, E.; Tisserand, V.; /Annecy, LAPP; Garra Tico, J.; Grauges, E.; /Barcelona U., ECM; Martinelli, M.; Palano, A.; Pappagallo, M.; /INFN, Bari /Bari U.; Eigen, G.; Stugu, B.; Sun, L.; /Bergen U.; Battaglia, M.; Brown, D.N.; Hooberman, B.; Kerth, L.T.; Kolomensky, Yu.G.; Lynch, G.; Osipenkov, I.L.; Tanabe, T.; /UC, Berkeley; Hawkes, C.M.; /Birmingham U. /Ruhr U., Bochum /British Columbia U. /Brunel U. /Novosibirsk, IYF /UC, Irvine /UC, Riverside /UC, San Diego /UC, Santa Barbara /UC, Santa Cruz /Caltech /Cincinnati U. /Colorado U. /Colorado State U. /Dortmund U. /Dresden, Tech. U. /Ecole Polytechnique /Edinburgh U. /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /INFN, Ferrara /INFN, Ferrara /Ferrara U. /Frascati /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /INFN, Genoa /INFN, Genoa /Genoa U. /Indian Inst. Tech., Guwahati /Harvard U. /Heidelberg U. /Humboldt U., Berlin /Imperial Coll., London /Iowa State U. /Iowa State U. /Johns Hopkins U. /Orsay, LAL /LLNL, Livermore /Liverpool U. /Queen Mary, U. of London /Royal Holloway, U. of London /Louisville U. /Mainz U., Inst. Kernphys. /Manchester U. /Maryland U. /Massachusetts U., Amherst /MIT /McGill U. /INFN, Milan /Milan U. /INFN, Milan /INFN, Milan /Milan U. /Mississippi U. /Montreal U. /INFN, Naples /Naples U. /NIKHEF, Amsterdam /Notre Dame U. /Ohio State U. /Oregon U. /INFN, Padua /Padua U. /INFN, Padua /INFN, Padua /Padua U. /Paris U., VI-VII /INFN, Perugia /Perugia U. /INFN, Pisa /Pisa U. /INFN, Pisa /Pisa, Scuola Normale Superiore /INFN, Pisa /Pisa U. /INFN, Pisa /Princeton U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /INFN, Rome /INFN, Rome /Rome U. /Rostock U. /Rutherford /DAPNIA, Saclay /SLAC /South Carolina U. /Stanford U., Phys. Dept. /SUNY, Albany /Tel Aviv U. /Tennessee U. /Texas U. /Texas U., Dallas /INFN, Turin /Turin U. /INFN, Trieste /Trieste U. /Valencia U. /Victoria U. /Warwick U. /Wisconsin U., Madison

    2010-06-04

    The branching fraction for the decay D{sub s}{sup +} {yields} {tau}{sup +}{nu}{sub {tau}} with {tau}{sup +} {yields} e{sup +}{bar {nu}}{sub {tau}}, is measured using a data sample corresponding to an integrated luminosity of 427 fb{sup -1} collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. In the process e{sup +}e{sup -} {yields} c{bar c} {yields} D*{sub s}{sup +} {bar D}{sub TAG}{bar K}X, the D*{sub s}{sup +} meson is reconstructed as a missing particle, and the subsequent decay D*{sub s}{sup +} {yields} D{sub s}{sup +}{gamma} yields an inclusive D{sub s}{sup +} data sample. Here {bar D}{sub TAG} refers to a fully reconstructed hadronic {bar D} decay, {bar K} is a K{sup -} or {bar K}{sup 0}, and X stands for any number of charged or neutral pions. The decay D{sub s}{sup +} {yields} K{sub S}{sup 0}K{sup +} is isolated also, and from ratio of event yields and known branching fractions, {Beta}(D{sub s}{sup +} {yields} {tau}{sup +}{nu}{sub {tau}}) = (4.5 {+-} 0.5 {+-} 0.4 {+-} 0.3)% is determined. The pseudoscalar decay constant is extracted to be f{sub D{sub s}} = (233 {+-} 13 {+-} 10 {+-} 7) MeV, where the first uncertainty is statistical, the second is systematic, and the third results from the uncertainties on the external measurements used as input to the calculation.

  16. Temporal upscaling of instantaneous evapotranspiration on clear-sky days using the constant reference evaporative fraction method with fixed or variable surface resistances at two cropland sites

    Science.gov (United States)

    Tang, Ronglin; Li, Zhao-Liang; Sun, Xiaomin; Bi, Yuyun

    2017-01-01

    Surface evapotranspiration (ET) is an important component of water and energy in land and atmospheric systems. This paper investigated whether using variable surface resistances in the reference ET estimates from the full-form Penman-Monteith (PM) equation could improve the upscaled daily ET estimates in the constant reference evaporative fraction (EFr, the ratio of actual to reference grass/alfalfa ET) method on clear-sky days using ground-based measurements. Half-hourly near-surface meteorological variables and eddy covariance (EC) system-measured latent heat flux data on clear-sky days were collected at two sites with different climatic conditions, namely, the subhumid Yucheng station in northern China and the arid Yingke site in northwestern China and were used as the model input and ground-truth, respectively. The results showed that using the Food and Agriculture Organization (FAO)-PM equation, the American Society of Civil Engineers-PM equation, and the full-form PM equation to estimate the reference ET in the constant EFr method produced progressively smaller upscaled daily ET at a given time from midmorning to midafternoon. Using all three PM equations produced the best results at noon at both sites regardless of whether the energy imbalance of the EC measurements was closed. When the EC measurements were not corrected for energy imbalance, using variable surface resistance in the full-form PM equation could improve the ET upscaling in the midafternoon, but worse results may occur in the midmorning to noon. Site-to-site and time-to-time variations were found in the performances of a given PM equation (with fixed or variable surface resistances) before and after the energy imbalance was closed.

  17. Opto-digital image encryption by using Baker mapping and 1-D fractional Fourier transform

    Science.gov (United States)

    Liu, Zhengjun; Li, She; Liu, Wei; Liu, Shutian

    2013-03-01

    We present an optical encryption method based on the Baker mapping in one-dimensional fractional Fourier transform (1D FrFT) domains. A thin cylinder lens is controlled by computer for implementing 1D FrFT at horizontal direction or vertical direction. The Baker mapping is introduced to scramble the amplitude distribution of complex function. The amplitude and phase of the output of encryption system are regarded as encrypted image and key. Numerical simulation has been performed for testing the validity of this encryption scheme.

  18. Design of Digital AGC Loops with Constant Settling Time%恒定建立时间数字AGC环路设计

    Institute of Scientific and Technical Information of China (English)

    周三文; 卢满宏; 黄建国

    2013-01-01

    针对传统恒定建立时间数字AGC(自动增益控制)环路实现方式复杂、成本高的问题,基于AGC环路的对数模型,推导出AGC环路建立时间恒定的条件,提出采用线性放大器实现恒定建立时间AGC环路的方法,该方法能够在数字实现上省去传统方式的指数运算单元,降低了实现复杂度和成本.另外,对于非突跳或突跳幅度较小输入信号,利用输出信号平方检测代替对数功率检测,省去传统方式的对数运算单元,进一步降低了实现复杂度和成本.通过上述2种改进,提出了一种简单的恒定建立时间数字AGC环路设计方法.Simulink仿真证明了该设计方法的正确性.该方法应用于无线数字接收机中,能够简化设计,节约成本.%Based on the logarithmic model of AGC (Automatic Gain Control),conditions for keeping constant settling time of AGC loops have been derived and a method using a linear amplifier to achieve a constant settling time AGC loop is proposed to simplify the design and reduce the cost of conventional constant settling time digital AGC loops.The exponential computing unit of the conventional method is eliminated,thus reducing the complexity and cost of implementation.Furthermore,square detection is used instead of the conventional logarithmic power detection for non-sudden jump or slight sudden jump input signals,and this lowers the cost further.Based on the two improvements,a simplified design method is proposed for constant settling time digital AGC loops.Correctness of the design method is proved by the simulation results.The method can be used in wireless digital receivers to simplify design and to save cost.

  19. 数字式LLC宽电压输出LED恒流驱动设计%Digital LLC wide voltage output LED constant current driver design

    Institute of Scientific and Technical Information of China (English)

    张绍军

    2015-01-01

    The LLC is a kind of high power converter topology, especially, with the growing trend of the LED module be in high voltage & low current. LLC has become a very appropriate choice of LED driver. The challenge exist in LLC design of wide voltage output constant current source , it is difficult to give attention to both high efficiency and low EMI and wide range of output voltage. Digital power supply with distinct advantage regarding as the overall cost, functionality, scalability, reliability, dimmer, the communication etc.This paper aims to put forward the new design concept of problem solving. A 200w prototype digital constant current source approached with digital processing, and 94% up system efficiency reached within twice as output of the voltage, as well as a good EMI performance fulfilled.%LLC是一种优良的电源转换拓扑,特别在LED模组在向高电压低电流方向发展时,LLC成为了LED驱动非常合适的选择。LLC在宽范围输出电压恒流源设计中存在着挑战,很难兼顾高效率、低的EMI和宽的输出电压范围。数字电源在整体成本、功能可扩展性、可靠性、调光、通信等方面具有明显的优势。本文针对问题提出了新的设计思路,并用数字式的方法去实现了一台200W数字式恒流源样机,在两倍的输出电压范围内实现系统效率94%以上,同时具有良好的EMI性能。

  20. Achromatic digital speckle pattern interferometer with constant radial in-plane sensitivity by using a diffractive optical element

    Energy Technology Data Exchange (ETDEWEB)

    Viotti, Matias R.; Kapp, Walter; Armando Albertazzi, G. Jr.

    2009-04-20

    We report on a digital speckle pattern interferometer that applies a binary diffractive optical element (DOE) to generate double illumination and radial in-plane sensitivity. The application of the DOE ensures independence on the wavelength of the laser used as an illumination source. Furthermore, in-plane sensitivity only depends on the grating period of the DOE. An experimental setup was built allowing the measurement of a set of radial in-plane displacement fields either using a red laser as a light source or a green one. When displacement fields computed from the measured optical phase maps obtained with a red or a green laser were compared, two main results were observed: (a) deviations between mean values ranged only up to 7 nm and (b) phase maps presented the same amount of fringes. In addition, phase maps measured with the red laser were processed as they were obtained with green light. For this case, deviations have ranged only up to 0.5 nm. On the other hand, a set of measurements performed changing the DOE by a conical mirror showed clearly that radial in-plane sensitivity increased when the red laser was changed by the green one.

  1. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    Processes of digitization have for years represented a major trend in the developments of modern society but have only recently been related to processes of mediatization. The purpose of this article is to look into the relation between the concepts of mediatization and digitization and to clarify...... what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...... not anticipated in previous conceptualizations of media and mediatization. If digital media are to be included, the concept of mediatization has to be revised and new parameters are to be built into the concept of media. At the same time it is argued that the concept of mediatization still provides a variety...

  2. Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

    Directory of Open Access Journals (Sweden)

    N. Belhaouchet

    2008-03-01

    Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.

  3. Varied tube potential with constant effective dose at lumbar spine radiography using a flat-panel digital detector.

    Science.gov (United States)

    Geijer, Håkan; Persliden, Jan

    2005-01-01

    The purpose of the study was to evaluate the image quality at different tube potential (kV) settings using anteroposterior lumbar spine radiography as a model. An Alderson phantom was used with a flat-panel detector. The tube potential varied between 48 and 125 kV while the tube charge (mAs) was adjusted to keep an effective dose of 0.11 mSv. Image quality was assessed with a visual grading analysis and with a CDRAD contrast-detail phantom together with a computer program. The VGA showed inferior image quality for the higher kV settings, > or =96 kVwith similar results for the contrast-detail phantom. When keeping the effective dose fixed, it seems beneficial to reduce kV to get the best image quality despite the fact that the mAs is not as high as with automatic exposure. However, this cannot be done with automatic exposure, which is set for a constant detector dose.

  4. 待定系数法解常系数齐次分数阶微分方程组%Solving Systems of Linear Fractional Differential Equations with Constant Coefficients by the Method of Undetermined Coefficients

    Institute of Scientific and Technical Information of China (English)

    代群; 李辉来

    2012-01-01

    用Jordan标准型方法研究常系数齐次分数阶微分方程组的基本解矩阵,得到了方程组的基本解系.结果表明,可以用待定系数法解常系数齐次分数阶微分方程组,并且该结果蕴含常系数线性一阶微分方程组.%The authors investigated the solution matrix of the systems of the linear fractional differential equations with constant coefficients, and obtained some exact solutions of the systems of linear equations using Jordan canonical matrix. We can solve the systems of linear fractional differential equations with constant coefficients using the method of undetermined coefficients, and the results contain the solution of linear first-order differential equations with constant coefficients.

  5. Digital constant current source based on the adjustable voltage regulator%基于可调稳压芯片的数控恒流源

    Institute of Scientific and Technical Information of China (English)

    苗新法

    2011-01-01

    Briefly discusses the design of DC constant current source, and discusses the existing devices, analyses their disadvantages,mainly introduces an efficient digital controlled constant current source which is based on adjustable voltage regulator. The schematic diagram of the circuit is given. The author introduces the principle of the system and the relation parameter in detail. Kernel model and feedback model are introduced from the point of view of system composition. The principle of the system is using the kernel chip's feedback pin, changing the parallel feedback to serial feedback. This system has function of current preset and low current ripple etc. An instrument developed by the author employs the constant current circuit designed in this paper and has got popular applications.%针对数控直流恒流源的设计进行了探讨,对比已有的恒流源实现方式,分析了其缺点,重点介绍1种高效率的基于可调稳压芯片的数控恒流源.给出了电路原理图,就整机工作原理、相关参数计算做了详细介绍.从系统组成角度分别介绍了核心模块、反馈模块及其实现方法.其基本原理是利用核心芯片的反馈引脚,把并联反馈改为串联反馈,从而实现恒流性能.系统具有输出电流可预置,输出纹波电流低等特性.采用设计的恒流源电路在自行研制的某仪器已推广应用.

  6. The use of digital simulation to improve the cyclic voltammetric determination of rate constants for homogeneous chemical reactions following charge transfers

    Energy Technology Data Exchange (ETDEWEB)

    Mozo, J.D.; Carbajo, J. [Applied Electrochemistry Laboratory, Dep. of Chemical Enginery, Physical Chemistry and Organic Chemistry, Experimental Sciences Faculty, University of Huelva, Av. 3 de Marzo, s/n (Campus El Carmen), ES-21071 Huelva (Spain); Sturm, J.C.; Nunez-Vergara, L.J.; Moscoso, R. [Bioelectrochemistry Laboratory, Chemical and Pharmaceutical Sciences Faculty, University of Chile, 838492 Santiago (Chile); Squella, J.A., E-mail: asquella@ciq.uchile.cl [Bioelectrochemistry Laboratory, Chemical and Pharmaceutical Sciences Faculty, University of Chile, 838492 Santiago (Chile)

    2011-08-05

    Cyclic voltammetry (CV) is a very useful electrochemical tool used to study reaction systems that include chemical steps that are coupled to electron transfers. This type of system generally involves the chemical reaction of an electrochemically generated free radical. Published methods exist that are used to determine the kinetics of electrochemically initiated chemical reactions from the measurements of the peak current ratio (i{sub pa}/i{sub pc}) of a cyclic voltammogram. The published method requires working curves to relate a kinetic parameter to the peak current ratio. In the presented work, a digital simulation package was used to obtain improved working curves for specific working conditions. The curves were compared with the published results for the first- and second-order chemical reactions following the charge transfer step mechanisms. According to the presented results, the previously published working curve is reliable for a mechanism with a first-order chemical reaction; however, a change in the switching potential requires a recalculation of the curve. In the case of mechanisms with a second-order step (dimerisation and disproportionation), several different views exist on how the second-order chemical term should be expressed so that different values of the constant are obtained. Parameters such as electrode type, electrode area, electroactive species concentration, switching potential, scan rate and method for peak current ratio calculation modify the working curves and must always be specified. We propose a standardised method to obtain the most reliable kinetic constant values. The results of this work will permit researchers who handle simulation software to construct their own working curves. Additionally, those who do not have the simulation software could use the working curves described here. The revelations of the presented experiments may be useful to a broad chemistry audience because this study presents a simple and low-cost procedure

  7. Searching for Kaprekar's constants: algorithms and results

    Directory of Open Access Journals (Sweden)

    Byron L. Walden

    2005-01-01

    Full Text Available We examine some new results on Kaprekar's constants, specifically establishing the unique 7-digit (in base 4 and 9-digit (in base 5 Kaprekar's constants and showing that there are no 15-, 21-, 27-, or 33-digit Kaprekar's constants.

  8. The use of digital simulation to improve the cyclic voltammetric determination of rate constants for homogeneous chemical reactions following charge transfers.

    Science.gov (United States)

    Mozo, J D; Carbajo, J; Sturm, J C; Núñez-Vergara, L J; Moscoso, R; Squella, J A

    2011-08-05

    Cyclic voltammetry (CV) is a very useful electrochemical tool used to study reaction systems that include chemical steps that are coupled to electron transfers. This type of system generally involves the chemical reaction of an electrochemically generated free radical. Published methods exist that are used to determine the kinetics of electrochemically initiated chemical reactions from the measurements of the peak current ratio (i(pa)/i(pc)) of a cyclic voltammogram. The published method requires working curves to relate a kinetic parameter to the peak current ratio. In the presented work, a digital simulation package was used to obtain improved working curves for specific working conditions. The curves were compared with the published results for the first- and second-order chemical reactions following the charge transfer step mechanisms. According to the presented results, the previously published working curve is reliable for a mechanism with a first-order chemical reaction; however, a change in the switching potential requires a recalculation of the curve. In the case of mechanisms with a second-order step (dimerisation and disproportionation), several different views exist on how the second-order chemical term should be expressed so that different values of the constant are obtained. Parameters such as electrode type, electrode area, electroactive species concentration, switching potential, scan rate and method for peak current ratio calculation modify the working curves and must always be specified. We propose a standardised method to obtain the most reliable kinetic constant values. The results of this work will permit researchers who handle simulation software to construct their own working curves. Additionally, those who do not have the simulation software could use the working curves described here. The revelations of the presented experiments may be useful to a broad chemistry audience because this study presents a simple and low-cost procedure for the

  9. A power-efficient 12-bit analog-to-digital converter with a novel constant-resistance CMOS input sampling switch

    Science.gov (United States)

    Xin, Jing; Yiqi, Zhuang; Hualian, Tang; Li, Dai; Yongqian, Du; Li, Zhang; Hongbo, Duan

    2014-02-01

    A power-efficient 12-bit 40-MS/s pipeline analog-to-digital converter (ADC) implemented in a 0.13 μm CMOS technology is presented. A novel CMOS bootstrapping switch, which offers a constant on-resistance over the entire input signal range, is used at the sample-and-hold front-end to enhance the dynamic performance of the pipelined ADC. By implementing with 2.5-bit-per-stage and a simplified amplifier sharing architecture between two successive pipeline stages, a very competitive power consumption and small die area can be achieved. Meanwhile, the substrate-biasing-effect attenuated T-type switches are introduced to reduce the crosstalk between the two opamp sharing successive stages. Moreover, a two-stage gain boosted recycling folded cascode (RFC) amplifier with hybrid frequency compensation is developed to further reduce the power consumption and maintain the ADC's performance simultaneously. The measured results imply that the ADC achieves a spurious-free dynamic range (SFDR) of 75.7 dB and a signal-to-noise-plus-distortion ratio (SNDR) of 62.74 dB with a 4.3 MHz input signal; the SNDR maintains over 58.25 dB for input signals up to 19.3MHz. The measured differential nonlinearity (DNL) and integral nonlinearity (INL) are -0.43 to +0.48 LSB and -1.62 to +1.89 LSB respectively. The prototype ADC consumes 28.4 mW under a 1.2-V nominal power supply and 40 MHz sampling rate, transferring to a figure-of-merit (FOM) of 0.63 pJ per conversion-step.

  10. DIGIT LENGTH DISPLAYS A SIGNIFICANT FRACTION IN STATURE ESTIMATION: A STUDY FROM COASTAL REGION OF SOUTH INDIA

    Directory of Open Access Journals (Sweden)

    Gayathri Matheswaran

    2014-06-01

    Full Text Available Relationship that exists between different part of the body and height had been of great interest to anthropologists, forensic and medical scientists for many years. This is because of the increase in the number of catastrophic events causing mass deaths from natural or manmade errors. Such disasters like flooding, tsunamis, earthquakes, plane crashes, train crashes , terrorist attacks usually requires the identification of victims from fragmentary and dismembered human remains. In present paper, study on stature estimation from digit length has been reported. In the present study, 200individuals (96 males and 104 females belonging to age group of 18 to 25years having no disease or deformity were examined anthropometrically in respect to their height and digit lengths (2D, 3D, 4D, 5D have been measured. The regression equations have been drawn from the data collected. It has been observed that stature can be estimated from the digit lengths

  11. The Field X-ray AGN Fraction to z=0.7 from the Chandra Multiwavelength Project and the Sloan Digital Sky Survey

    CERN Document Server

    Haggard, Daryl; Anderson, Scott F; Constantin, Anca; Aldcroft, Tom L; Kim, Dong-Woo; Barkhouse, Wayne A

    2010-01-01

    We employ the Chandra Multiwavelength Project (ChaMP) and the Sloan Digital Sky Survey (SDSS) to study the fraction of X-ray-active galaxies in the field out to z = 0.7. We utilize spectroscopic redshifts from SDSS and ChaMP, as well as photometric redshifts from several SDSS catalogs, to compile a parent sample of more than 100,000 SDSS galaxies and nearly 1,600 Chandra X-ray detections. Detailed ChaMP volume completeness maps allow us to investigate the local fraction of active galactic nuclei (AGN), defined as those objects having broad-band X-ray luminosities L_X (0.5-8 keV) > 10^42 erg s^-1, as a function of absolute optical magnitude, X-ray luminosity, redshift, mass, and host color/morphological type. In five independent samples complete in redshift and i-band absolute magnitude, we determine the field AGN fraction to be between 0.16 +/- 0.06% (for z M_i > -20) and 3.80 +/- 0.92% (for z < 0.7 and M_i < -23). We find striking agreement between our ChaMP/SDSS field AGN fraction and the Chandra clu...

  12. Method for the calculation of volumetric fraction of retained austenite through the software for analysis of digital images; Metodo para o calculo da fracao volumetrica de austenita retida atraves do software de analise digital de imagens

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, S.; Costa, F.H.; Hashimoto, T.M.; Pereira, M.S., E-mail: sandro_Lombardo@hotmail.co [UNESP, Guaratingueta, SP (Brazil). Fac. de Engenharia; Abdalla, A.J. [Centro Tecnico Aeroespacial (CTA-IEAv), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados

    2010-07-01

    In order to calculate the volume fraction of the retained austenite in aeronautic multiphase steels, it was used a digital analysis software for image processing. The materials studied were steels AISI 43XX with carbon content between 30, 40 and 50%, heat treated by conventional quenching and isothermal cooling in bainitic and intercritical region, characterized by optical microscopy, etching by reagent Sodium Metabisulfite (10%) for 30 seconds, with forced drying. The results were compared with the methods of X-Ray Diffraction and Magnetic Saturation through photomicrographs, showing that with this technic it is possible to quantify the percentage of retained austenite in the martensitic matrix, in the different types of steels. (author)

  13. Mystery Fractions

    Science.gov (United States)

    Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max

    2016-01-01

    Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…

  14. Mystery Fractions

    Science.gov (United States)

    Bhattacharyya, Sonalee; Namakshi, Nama; Zunker, Christina; Warshauer, Hiroko K.; Warshauer, Max

    2016-01-01

    Making math more engaging for students is a challenge that every teacher faces on a daily basis. These authors write that they are constantly searching for rich problem-solving tasks that cover the necessary content, develop critical-thinking skills, and engage student interest. The Mystery Fraction activity provided here focuses on a key number…

  15. Estimation of channel mismatches in time-interleaved analog-to-digital converters based on fractional delay and sine curve fitting.

    Science.gov (United States)

    Guo, Lianping; Tian, Shulin; Jiang, Jun

    2015-03-01

    This paper proposes an algorithm to estimate the channel mismatches in time-interleaved analog-to-digital converter (TIADC) based on fractional delay (FD) and sine curve fitting. Choose one channel as the reference channel and apply FD to the output samples of reference channel to obtain the ideal samples of non-reference channels with no mismatches. Based on least square method, the sine curves are adopted to fit the ideal and the actual samples of non-reference channels, and then the mismatch parameters can be estimated by comparing the ideal sine curves and the actual ones. The principle of this algorithm is simple and easily understood. Moreover, its implementation needs no extra circuits, lowering the hardware cost. Simulation results show that the estimation accuracy of this algorithm can be controlled within 2%. Finally, the practicability of this algorithm is verified by the measurement results of channel mismatch errors of a two-channel TIADC prototype.

  16. Varying Constants

    CERN Document Server

    Damour, Thibault Marie Alban Guillaume

    2003-01-01

    We review some string-inspired theoretical models which incorporate a correlated spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring unnatural fine-tunings of parameters, a variation of the fine-structure constant as large as that recently ``observed'' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universality of free fall, such as MICROSCOPE and STEP. Recent claims by Bekenstein that fine-structure-constant variability does not imply detectable violations of the equivalence principle are shown to be untenable.

  17. Pattern recognition in the ALFALFA.70 and Sloan Digital Sky Surveys: A catalog of $\\sim$ 500,000 HI gas fraction estimates based on artificial neural networks

    CERN Document Server

    Teimoorinia, Hossen; Patton, David R

    2016-01-01

    The application of artificial neural networks (ANNs) for the estimation of HI gas mass fraction (\\fgas) is investigated, based on a sample of 13,674 galaxies in the Sloan Digital Sky Survey (SDSS) with HI detections or upper limits from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). We show that, for an example set of fixed input parameters ($g-r$ colour and $i$-band surface brightness), a multidimensional quadratic model yields \\fgas\\ scaling relations with a smaller scatter (0.22 dex) than traditional linear fits (0.32 dex), demonstrating that non-linear methods can lead to an improved performance over traditional approaches. A more extensive ANN analysis is performed using 15 galaxy parameters that capture variation in stellar mass, internal structure, environment and star formation. Of the 15 parameters investigated, we find that $g-r$ colour, followed by stellar mass surface density, bulge fraction and specific star formation rate have the best connection with \\fgas. By combining two contro...

  18. Bulge mass is king: The dominant role of the bulge in determining the fraction of passive galaxies in the Sloan Digital Sky Survey

    CERN Document Server

    Bluck, Asa F L; Ellison, Sara L; Moreno, Jorge; Simard, Luc; Patton, David R; Starkenburg, Else

    2014-01-01

    We investigate the origin of galaxy bimodality by quantifying the relative role of intrinsic and environmental drivers to the cessation (or `quenching') of star formation in over half a million local Sloan Digital Sky Survey (SDSS) galaxies. Our sample contains a wide variety of galaxies at z=0.02-0.2, with stellar masses of 8 < log(M*/M_sun) < 12, spanning the entire morphological range from pure disks to spheroids, and over four orders of magnitude in local galaxy density and halo mass. We utilise published star formation rates and add to this recent GIM2D photometric and stellar mass bulge + disk decompositions from our group. We find that the passive fraction of galaxies increases steeply with stellar mass, halo mass, and bulge mass, with a less steep dependence on local galaxy density and bulge-to-total stellar mass ratio (B/T). At fixed internal properties, we find that central and satellite galaxies have different passive fraction relationships. For centrals, we conclude that there is less variat...

  19. MATHEMATICAL CONSTANTS.

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, H.P.; Potter, Elinor

    1971-03-01

    This collection of mathematical data consists of two tables of decimal constants arranged according to size rather than function, a third table of integers from 1 to 1000, giving some of their properties, and a fourth table listing some infinite series arranged according to increasing size of the coefficients of the terms. The decimal values of Tables I and II are given to 20 D.

  20. Hemaka's constant

    CERN Document Server

    Sparavigna, Amelia Carolina

    2012-01-01

    As proposed in a previous paper, the decorations of ancient objects can provide some information on the approximate evaluations of constant {\\pi}, the ratio of circumference to diameter. Here we discuss some disks found in the tomb of Hemaka, the chancellor of a king of the First Dynasty of Egypt, about 3000 BC. The discussion is based on measurements of the dimensionless ratio of lengths.

  1. 全数字电枢电流控制卷取机恒张力系统%All-Digital Armature Current Controller for Constant Tensile-stress

    Institute of Scientific and Technical Information of China (English)

    孟文博; 孟文涛

    2000-01-01

    Using 8031 to control armature current for constant tensil-stress reel control system has been studied. The control method for diameter filter and dynamic current filteris is discussed%利用8031实现电枢电流控制的卷取机恒张力控 制,同时研究了卷径滤波、动态电流滤波的必要性和实现方法.该模型已成功地 在工厂使用

  2. Pattern recognition in the ALFALFA.70 and Sloan Digital Sky Surveys: a catalogue of ˜500 000 H I gas fraction estimates based on artificial neural networks

    Science.gov (United States)

    Teimoorinia, Hossen; Ellison, Sara L.; Patton, David R.

    2017-02-01

    The application of artificial neural networks (ANNs) for the estimation of H I gas mass fraction (M_{H I}/{{M}_{*}}) is investigated, based on a sample of 13 674 galaxies in the Sloan Digital Sky Survey (SDSS) with H I detections or upper limits from the Arecibo Legacy Fast Arecibo L-band Feed Array (ALFALFA). We show that, for an example set of fixed input parameters (g - r colour and i-band surface brightness), a multidimensional quadratic model yields M_{H I}/{{M}_{*}} scaling relations with a smaller scatter (0.22 dex) than traditional linear fits (0.32 dex), demonstrating that non-linear methods can lead to an improved performance over traditional approaches. A more extensive ANN analysis is performed using 15 galaxy parameters that capture variation in stellar mass, internal structure, environment and star formation. Of the 15 parameters investigated, we find that g - r colour, followed by stellar mass surface density, bulge fraction and specific star formation rate have the best connection with M_{H I}/{{M}_{*}}. By combining two control parameters, that indicate how well a given galaxy in SDSS is represented by the ALFALFA training set (PR) and the scatter in the training procedure (σfit), we develop a strategy for quantifying which SDSS galaxies our ANN can be adequately applied to, and the associated errors in the M_{H I}/{{M}_{*}} estimation. In contrast to previous works, our M_{H I}/{{M}_{*}} estimation has no systematic trend with galactic parameters such as M⋆, g - r and star formation rate. We present a catalogue of M_{H I}/{{M}_{*}} estimates for more than half a million galaxies in the SDSS, of which ˜150 000 galaxies have a secure selection parameter with average scatter in the M_{H I}/{{M}_{*}} estimation of 0.22 dex.

  3. Design of Constant-Gain Digitally Controlled Oscillator%增益恒定的数控振荡器设计

    Institute of Scientific and Technical Information of China (English)

    陈鑫; 黄辉; 吴宁

    2012-01-01

    针对驱动能力可调的数控振荡器在输出频率范围内增益变化较大的问题,提出了一种电路设计方法,通过该方法设计出的数控振荡器结构具有增益恒定的特点.在SMIC 0.18 μm logic 1P6M CMOS工艺下设计并实现了一个采用该振荡器结构的数控锁相环,数控振荡器的面积为0.025 mm2.实测数据表明,该数控振荡器输出的频率范围为76 ~ 208 MHz.当锁相环输出208 MHz高频时钟时,四分频后的峰峰值抖动为110 ps,均方根抖动为14.82 ps,数控振荡器的功耗为1.512 mW.%The gain of the driven-adjustable digitally controlled oscillator (DCO) varies largely in the output frequency range. To solve the problem, a circuit design method is presented to keep the DCO gain invariant in time-domain. To verify the proposed design method, a digitally controlled phase-locked loop (DCPLL) with the DCO is implemented by SMIC 0.18 祄 logic 1P6M CMOS technology. The area of the DCO is 0.025 mm2. The measured results show that the frequency range of the DCO is from 76 MHz to 208 MHz. When the frequency of the DCO is 208 MHz, the measured peak-to-peak jitter and cycle jitter of the corresponding four-divided clock are 110 ps and 14.82 ps, respectively. The corresponding power of the DCO is 1.512 mW.

  4. How Weird Are Weird Fractions?

    Science.gov (United States)

    Stuffelbeam, Ryan

    2013-01-01

    A positive rational is a weird fraction if its value is unchanged by an illegitimate, digit-based reduction. In this article, we prove that each weird fraction is uniquely weird and initiate a discussion of the prevalence of weird fractions.

  5. Automated quantification of aortic regurgitant volume and regurgitant fraction using the digital colour Doppler velocity profile integration method in patients with aortic regurgitation

    OpenAIRE

    Miyake, Y.; Hozumi, T; Mori, I.; Sugioka, K; Yamamuro, A; Akasaka, T; Homma, S; Yoshida, K.; Yoshikawa, J

    2002-01-01

    Background: The recently introduced automated cardiac flow measurement (ACM) technique provides a quick and an accurate automated calculation of stroke volume and cardiac output. This is obtained by spatio-temporal integration of digital Doppler velocity profile data.

  6. A Digital Image Enhancement Algorithm Based on Fractional Difference%数字图像的分数阶微分增强

    Institute of Scientific and Technical Information of China (English)

    何远德

    2013-01-01

    In order to improve equality of texture, a fractional differential image enhancement algorithm is proposed in this paper. First, discrete expression of fractional differential equations is deduced, and then is extended to two-dimensional image space; furthermore, the rules and mask of fractional differential image enhancement are constructed. The experiments shows that the fractional differential enhancement algorithm can obviously enhance the texture details of the image; and the clarity of enhanced image is significantly improved.%为了提高图像的纹理细节,提出了一种分数阶对比度增强算法。首先离散化分数阶微分方程得到分数阶微分数值计算方法,并将其推广到二维图像空间,构造了数字图像的分数阶微分增强运算规则和增强模板。实验表明该分数阶微分增强算法能比较明显地增强图像的纹理细节,增强后的图像清晰度显著提高。

  7. Ferroelectric Fractional-Order Capacitors

    KAUST Repository

    Agambayev, Agamyrat

    2017-07-25

    Poly(vinylidene fluoride)-based polymers and their blends are used to fabricate electrostatic fractional-order capacitors. This simple but effective method allows us to precisely tune the constant phase angle of the resulting fractional-order capacitor by changing the blend composition. Additionally, we have derived an empirical relation between the ratio of the blend constituents and the constant phase angle to facilitate the design of a fractional order capacitor with a desired constant phase angle. The structural composition of the fabricated blends is investigated using Fourier transform infrared spectroscopy and X-ray diffraction techniques.

  8. Fractional random walk lattice dynamics

    CERN Document Server

    Michelitsch, Thomas; Riascos, Alejandro Perez; Nowakowski, Andrzeij; Nicolleau, Franck

    2016-01-01

    We analyze time-discrete and continuous `fractional' random walks on undirected regular networks with special focus on cubic periodic lattices in $n=1,2,3,..$ dimensions.The fractional random walk dynamics is governed by a master equation involving {\\it fractional powers of Laplacian matrices $L^{\\frac{\\alpha}{2}}$}where $\\alpha=2$ recovers the normal walk.First we demonstrate thatthe interval $0\\textless{}\\alpha\\leq 2$ is admissible for the fractional random walk. We derive analytical expressions for fractional transition matrix and closely related the average return probabilities. We further obtain thefundamental matrix $Z^{(\\alpha)}$, and the mean relaxation time (Kemeny constant) for the fractional random walk.The representation for the fundamental matrix $Z^{(\\alpha)}$ relates fractional random walks with normal random walks.We show that the fractional transition matrix elements exihibit for large cubic $n$-dimensional lattices a power law decay of an $n$-dimensional infinite spaceRiesz fractional deriva...

  9. Fractional Echoes

    CERN Document Server

    Karras, G; Billard, F; Lavorel, B; Siour, G; Hartmann, J -M; Faucher, O; Gershnabel, Erez; Prior, Yehiam; Averbukh, Ilya Sh

    2016-01-01

    We report the observation of fractional echoes in a double-pulse excited nonlinear system. Unlike standard echoes which appear periodically at delays which are integer multiple of the delay between the two exciting pulses, the fractional echoes appear at rational fractions of this delay. We discuss the mechanism leading to this phenomenon, and provide the first experimental demonstration of fractional echoes by measuring third harmonic generation in a thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.

  10. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  11. FRACTIONAL BANKING

    OpenAIRE

    Maria Klimikova

    2010-01-01

    Understanding the reasons of the present financial problems lies In understanding the substance of fractional reserve banking. The substance of fractional banking is in lending more money than the bankers have. Banking of partial reserves is an alternative form which links deposit banking and credit banking. Fractional banking is causing many unfavorable economic impacts in the worldwide system, specifically an inflation.

  12. Fractional randomness

    Science.gov (United States)

    Tapiero, Charles S.; Vallois, Pierre

    2016-11-01

    The premise of this paper is that a fractional probability distribution is based on fractional operators and the fractional (Hurst) index used that alters the classical setting of random variables. For example, a random variable defined by its density function might not have a fractional density function defined in its conventional sense. Practically, it implies that a distribution's granularity defined by a fractional kernel may have properties that differ due to the fractional index used and the fractional calculus applied to define it. The purpose of this paper is to consider an application of fractional calculus to define the fractional density function of a random variable. In addition, we provide and prove a number of results, defining the functional forms of these distributions as well as their existence. In particular, we define fractional probability distributions for increasing and decreasing functions that are right continuous. Examples are used to motivate the usefulness of a statistical approach to fractional calculus and its application to economic and financial problems. In conclusion, this paper is a preliminary attempt to construct statistical fractional models. Due to the breadth and the extent of such problems, this paper may be considered as an initial attempt to do so.

  13. Fractional thermoelasticity

    CERN Document Server

    Povstenko, Yuriy

    2015-01-01

    This book is devoted to fractional thermoelasticity, i.e. thermoelasticity based on the heat conduction equation with differential operators of fractional order. Readers will discover how time-fractional differential operators describe memory effects and space-fractional differential operators deal with the long-range interaction. Fractional calculus, generalized Fourier law, axisymmetric and central symmetric problems and many relevant equations are featured in the book. The latest developments in the field are included and the reader is brought up to date with current research.  The book contains a large number of figures, to show the characteristic features of temperature and stress distributions and to represent the whole spectrum of order of fractional operators.  This work presents a picture of the state-of-the-art of fractional thermoelasticity and is suitable for specialists in applied mathematics, physics, geophysics, elasticity, thermoelasticity and engineering sciences. Corresponding sections of ...

  14. Ion exchange equilibrium constants

    CERN Document Server

    Marcus, Y

    2013-01-01

    Ion Exchange Equilibrium Constants focuses on the test-compilation of equilibrium constants for ion exchange reactions. The book first underscores the scope of the compilation, equilibrium constants, symbols used, and arrangement of the table. The manuscript then presents the table of equilibrium constants, including polystyrene sulfonate cation exchanger, polyacrylate cation exchanger, polymethacrylate cation exchanger, polysterene phosphate cation exchanger, and zirconium phosphate cation exchanger. The text highlights zirconium oxide anion exchanger, zeolite type 13Y cation exchanger, and

  15. Rational Exponentials and Continued Fractions

    Science.gov (United States)

    Denny, J. K.

    2012-01-01

    Using continued fraction expansions, we can approximate constants, such as pi and e, using an appropriate integer n raised to the power x[superscript 1/x], x a suitable rational. We review continued fractions and give an algorithm for producing these approximations.

  16. Cosmological Constant, Fine Structure Constant and Beyond

    CERN Document Server

    Wei, Hao; Li, Hong-Yu; Xue, Dong-Ze

    2016-01-01

    In this work, we consider the cosmological constant model $\\Lambda\\propto\\alpha^{-6}$, which is well motivated from three independent approaches. As is well known, the evidence of varying fine structure constant $\\alpha$ was found in 1998. If $\\Lambda\\propto\\alpha^{-6}$ is right, it means that the cosmological constant $\\Lambda$ should be also varying. In this work, we try to develop a suitable framework to model this varying cosmological constant $\\Lambda\\propto\\alpha^{-6}$, in which we view it from an interacting vacuum energy perspective. We propose two types of models to describe the evolutions of $\\Lambda$ and $\\alpha$. Then, we consider the observational constraints on these models, by using the 293 $\\Delta\\alpha/\\alpha$ data from the absorption systems in the spectra of distant quasars, and the data of type Ia supernovae (SNIa), cosmic microwave background (CMB), baryon acoustic oscillation (BAO). We find that the model parameters can be tightly constrained to the narrow ranges of ${\\cal O}(10^{-5})$ t...

  17. Analysis of digital timing methods with DRS4 board

    CERN Document Server

    Du, Cheng-Ming; Yang, Hai-Bo; Cheng, Ke; Zhang, Xiu-Ling; Xu, Hu-Shan; Hu, Zheng-Guo; Sun, Zhi-Yu

    2015-01-01

    Digital Pulse Processing (DPP) modules are being used to replace the analog electronics modular in modern physics experiments for processing the original signals from detectors. A new DPP modules based on domino ring sampler version 4 (DRS4) and multiple methods for processing arrival times are presented in this paper. In the experiments, the detectors were irradiated with 511keV gama ray from a 22Na source.The detectors consitsts of LaBr3 scintillators and XP20D0 Photomultiplier Tubes(PMTs), and the acquiring system was a 8+1 channels DRS4 board.Multiple DPP including (1)leading-edge discrimination, (2)constant-fraction zero-crossing discrimination and (3)digital constant fraction discrimination were inverstigated. The best time resolution is 194.7ps FWHM, obtained by constant fraction discrimination method, which is better than the other DPP methods and the traditional analog systems using the same detectors. The DRS4 board and DPP methods can be applied to supplement positron emission tomography (PET) with...

  18. On the constants for some Sobolev imbeddings

    Directory of Open Access Journals (Sweden)

    Pizzocchero Livio

    2001-01-01

    Full Text Available We consider the imbedding inequality is the Sobolev space (or Bessel potential space of type and (integer or fractional order . We write down upper bounds for the constants , using an argument previously applied in the literature in particular cases. We prove that the upper bounds computed in this way are in fact the sharp constants if , , and exhibit the maximising functions. Furthermore, using convenient trial functions, we derive lower bounds on for in many cases these are close to the previous upper bounds, as illustrated by a number of examples, thus characterizing the sharp constants with little uncertainty.

  19. Fractional motions

    Energy Technology Data Exchange (ETDEWEB)

    Eliazar, Iddo I., E-mail: eliazar@post.tau.ac.il [Holon Institute of Technology, P.O. Box 305, Holon 58102 (Israel); Shlesinger, Michael F., E-mail: mike.shlesinger@navy.mil [Office of Naval Research, Code 30, 875 N. Randolph St., Arlington, VA 22203 (United States)

    2013-06-10

    Brownian motion is the archetypal model for random transport processes in science and engineering. Brownian motion displays neither wild fluctuations (the “Noah effect”), nor long-range correlations (the “Joseph effect”). The quintessential model for processes displaying the Noah effect is Lévy motion, the quintessential model for processes displaying the Joseph effect is fractional Brownian motion, and the prototypical model for processes displaying both the Noah and Joseph effects is fractional Lévy motion. In this paper we review these four random-motion models–henceforth termed “fractional motions” –via a unified physical setting that is based on Langevin’s equation, the Einstein–Smoluchowski paradigm, and stochastic scaling limits. The unified setting explains the universal macroscopic emergence of fractional motions, and predicts–according to microscopic-level details–which of the four fractional motions will emerge on the macroscopic level. The statistical properties of fractional motions are classified and parametrized by two exponents—a “Noah exponent” governing their fluctuations, and a “Joseph exponent” governing their dispersions and correlations. This self-contained review provides a concise and cohesive introduction to fractional motions.

  20. Generalized Pickands constants

    NARCIS (Netherlands)

    Debicki, K.G.

    2001-01-01

    Pickands constants play an important role in the exact asymptotic of extreme values for Gaussian stochastic processes. By the {it generalized Pickands constant ${cal H_{eta$ we mean the limit begin{eqnarray* {cal H_{eta= lim_{T to inftyfrac{ {cal H_{eta(T){T, end{eqnarray* where ${cal H_{eta(T)= Exp

  1. Multiple constant multiplication optimizations for field programmable gate arrays

    CERN Document Server

    Kumm, Martin

    2016-01-01

    This work covers field programmable gate array (FPGA)-specific optimizations of circuits computing the multiplication of a variable by several constants, commonly denoted as multiple constant multiplication (MCM). These optimizations focus on low resource usage but high performance. They comprise the use of fast carry-chains in adder-based constant multiplications including ternary (3-input) adders as well as the integration of look-up table-based constant multipliers and embedded multipliers to get the optimal mapping to modern FPGAs. The proposed methods can be used for the efficient implementation of digital filters, discrete transforms and many other circuits in the domain of digital signal processing, communication and image processing. Contents Heuristic and ILP-Based Optimal Solutions for the Pipelined Multiple Constant Multiplication Problem Methods to Integrate Embedded Multipliers, LUT-Based Constant Multipliers and Ternary (3-Input) Adders An Optimized Multiple Constant Multiplication Architecture ...

  2. A 0.8V, 7μA, rail-to-rail input/output, constant Gm operational amplifier in standard digital 0.18μm CMOS

    DEFF Research Database (Denmark)

    Citakovic, J; Nielsen, I. Riis; Nielsen, Jannik Hammel

    2005-01-01

    A two-stage amplifier, operational at 0.8V and drawing 7μA, has been integrated in a standard digital 0.18μm CMOS process. Rail-to-rail operations at the input are enabled by complementary transistor pairs with gm control. The efficient rail-to-rail output stage is biased in class AB. The measured...... DC gain of the amplifier is 75dB, and the unity-gain frequency is 870kHz with a 12pF, 100kΩload. Both input and output stage transistors are biased in weak inversion....

  3. Polymer fractionation

    Energy Technology Data Exchange (ETDEWEB)

    Hadermann, A. F.

    1985-04-09

    Soluble polymers are fractionated according to molecular weight by cryogenically comminuting the polymer and introducing the polymer particles, while still in the active state induced by cryogenic grinding, into a liquid having a solvent power selected to produce a coacervate fraction containing high molecular weight polymer species and a dilute polymer solution containing lower molecular weight polymer species. The coacervate may be physically separated from the solution and finds use in the production of antimisting jet fuels and the like.

  4. Understanding Multiplication of Fractions.

    Science.gov (United States)

    Sweetland, Robert D.

    1984-01-01

    Discussed the use of Cuisenaire rods in teaching the multiplication of fractions. Considers whole number times proper fraction, proper fraction multiplied by proper fraction, mixed number times proper fraction, and mixed fraction multiplied by mixed fractions. (JN)

  5. On Generalized Fractional Differentiator Signals

    Directory of Open Access Journals (Sweden)

    Hamid A. Jalab

    2013-01-01

    Full Text Available By employing the generalized fractional differential operator, we introduce a system of fractional order derivative for a uniformly sampled polynomial signal. The calculation of the bring in signal depends on the additive combination of the weighted bring-in of N cascaded digital differentiators. The weights are imposed in a closed formula containing the Stirling numbers of the first kind. The approach taken in this work is to consider that signal function in terms of Newton series. The convergence of the system to a fractional time differentiator is discussed.

  6. A DSP equipped digitizer for online analysis of nuclear detector signals

    Energy Technology Data Exchange (ETDEWEB)

    Pasquali, G. [INFN and Department of Physics, University of Florence, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy)]. E-mail: pasquali@fi.infn.it; Ciaranfi, R. [INFN - Sezione di Firenze, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy); Bardelli, L. [INFN and Department of Physics, University of Florence, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy); Bini, M. [INFN and Department of Physics, University of Florence, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy); Boiano, A. [INFN - Sezione di Napoli, Via Cintia, Naples 80126 (Italy); Giannelli, F. [INFN and Department of Physics, University of Florence, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy); Ordine, A. [INFN - Sezione di Napoli, Via Cintia, Naples 80126 (Italy); Poggi, G. [INFN and Department of Physics, University of Florence, Via G.Sansone 1, Sesto Fiorentino 50019 (Italy)

    2007-01-01

    In the framework of the NUCL-EX collaboration, a DSP equipped fast digitizer has been implemented and it has now reached the production stage. Each sampling channel is implemented on a separate daughter-board to be plugged on a VME mother-board. Each channel features a 12-bit, 125 MSamples/s ADC and a Digital Signal Processor (DSP) for online analysis of detector signals. A few algorithms have been written and successfully tested on detectors of different types (scintillators, solid-state, gas-filled), implementing pulse shape discrimination, constant fraction timing, semi-Gaussian shaping, gated integration.

  7. Design of precision digital constant current source based on the MAX5494%基于MCS1210精密电阻仪的设计与实现

    Institute of Scientific and Technical Information of China (English)

    杜军; 杜乾

    2014-01-01

    The paper introduces the versatile microcontroller MSC1210 and 16 bit D/A converter AD5061 , and precision resistance meter design ideas and working principle, highlights key components selection and low temperature drift precision constant current source circuit design. It achieves the goals of high precision constant current output and finely measurement by adopting external closed-loop feedback error adjustment system of the output current by using the A/D converter to the microcontroller and internal closed-loop stabilization system constituted by an operational amplifier such as the depth of the negative feedback.%介绍了多功能单片机 MSC1210和16位 D/A 转换器 AD5061的功能特点及精密电阻仪的设计思想和工作原理,突出关键器件的选用和高精度低温漂恒流源电路设计。采用输出电流经 A/D转换反馈回单片机的外部闭环误差调整和由运算放大器等构成深度负反馈的内部闭环稳定系统,实现高精度恒流输出和精细测量目标。

  8. Analysis of Digital Voltage-Mode Controlled Buck Converter with Dual-Edge Constant on-Time Modulation%双缘COT调制数字电压型控制Buck变换器分析

    Institute of Scientific and Technical Information of China (English)

    周国华; 陈兴; 崔恒丰

    2015-01-01

    为了提高恒定导通时间(constant on-time,COT)调制开关变换器的输出电压稳压精度,基于COT调制和双缘脉冲宽度调制的特点,提出了一种工作于电感电流连续导电模式(continuous conduction mode,CCM)的开关变换器双缘恒定导通时间(dual-edge constant on-time,DCOT)调制方法.介绍了DCOT调制数字电压型控制Buck变换器的工作原理,对比分析了COT调制和DCOT调制数字电压型控制Buck变换器的稳态性能和瞬态性能.结果表明:相比于COT调制,采用DCOT调制的数字电压型控制Buck变换器提高了输出电压的稳压精度,其大小为输出电压纹波峰峰值的50%,且瞬态调节时间减少了1个开关周期.最后,通过仿真和实验结果证明了理论分析的正确性.

  9. Incompressible Stars and Fractional Derivatives

    CERN Document Server

    Bayin, S S

    2014-01-01

    Fractional calculus is an effective tool in incorporating the effects of non-locality and memory into physical models. In this regard, successful applications exist rang- ing from signal processing to anomalous diffusion and quantum mechanics. In this paper we investigate the fractional versions of the stellar structure equations for non radiating spherical objects. Using incompressible fluids as a comparison, we develop models for constant density Newtonian objects with fractional mass distributions or stress conditions. To better understand the fractional effects, we discuss effective values for the density, gravitational field and equation of state. The fractional ob- jects are smaller and less massive than integer models. The fractional parameters are related to a polytropic index for the models considered.

  10. Fine-structure constant: Is it really a constant?

    Science.gov (United States)

    Bekenstein, Jacob D.

    1982-03-01

    It is often claimed that the fine-structure "constant" α is shown to be strictly constant in time by a variety of astronomical and geophysical results. These constrain its fractional rate of change α˙α to at least some orders of magnitude below the Hubble rate H0. We argue that the conclusion is not as straightforward as claimed since there are good physical reasons to expect α˙α<

  11. An Automatic Extraction Approach to Fractional Vegetation Cover of Saline Land with Digital Images%吉林西部盐碱地数字图像植被覆盖度的自动提取

    Institute of Scientific and Technical Information of China (English)

    丁艳玲; 赵凯; 李晓峰; 郑兴明

    2013-01-01

      植被覆盖度是生态环境变化的重要指标,也是遥感反演的关键参数。盐碱地植被覆盖度的准确测量对研究地表植被蒸腾、土壤水分蒸发及土壤退化、盐碱化等具有重要意义。过绿指数(Excess Green index,ExG)对绿色植被比较敏感,能突显植被信息,去除土壤、阴影的干扰。通过对吉林西部盐碱地玉米、高粱、绿豆、杂草、土壤数字图像特征分析,利用改进过绿指数(Modified Excess Green index,MExG)算法计算植被和土壤的MExG值;并确定区分植被和土壤的MExG阈值为40,进而计算植被覆盖度。本文采用监督分类的最大似然法对比验证MExG自动提取结果,并对两种方法计算的玉米、高粱、绿豆和杂草的覆盖度,分别进行目视判读和t检验。研究表明,MExG自动提取方法具有客观性强,处理时间短,分类精度高等优点,是计算不同植被类型覆盖度的有效方法。%Fractional vegetation cover is an important variable in ecological environment and a key parameter in remote sensing estimation, which is needed in the modeling of the land-atmosphere exchanges of momentum, en-ergy, water, and trace gases. Determination of fractional vegetation cover exactly is necessary for studies on plant transpiration, ground surface evaporation, soil degradation and salinization. Excess green, highlighting veg-etation and inhibiting the interference of soil and shadow, was used as a contrast enhancement for identifying plants from soil regions. This study uses modified excess green index to extract fractional vegetation cover by an-alyzing RGB color features of corn, sorghum, mung beans and weeds growing in saline land in western Jilin Province. The digital images are geometrically corrected in order to eliminate distortion. The automatic extrac-tion approach using modified excess green indexes which is about 40 for vegetation growing on the saline land of western

  12. Variation of Fundamental Constants

    Science.gov (United States)

    Flambaum, V. V.

    2006-11-01

    Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. The spatial variation can explain a fine tuning of the fundamental constants which allows humans (and any life) to appear. We appeared in the area of the Universe where the values of the fundamental constants are consistent with our existence. We present a review of recent works devoted to the variation of the fine structure constant α, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra. Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feshbach resonance.

  13. Teaching Fractions

    Science.gov (United States)

    McLeman, Laura Kondek; Cavell, Heather A.

    2009-01-01

    Teacher educators are constantly searching for ways to better prepare preservice teachers to enter the education field. One way that has gained prominence in the last twenty years is through examining and discussing authentic student work samples. Research suggests that doing so helps preservice teachers to (1) gain insight into their own beliefs…

  14. Elastic constants of calcite

    Science.gov (United States)

    Peselnick, L.; Robie, R.A.

    1962-01-01

    The recent measurements of the elastic constants of calcite by Reddy and Subrahmanyam (1960) disagree with the values obtained independently by Voigt (1910) and Bhimasenachar (1945). The present authors, using an ultrasonic pulse technique at 3 Mc and 25??C, determined the elastic constants of calcite using the exact equations governing the wave velocities in the single crystal. The results are C11=13.7, C33=8.11, C44=3.50, C12=4.82, C13=5.68, and C14=-2.00, in units of 1011 dyncm2. Independent checks of several of the elastic constants were made employing other directions and polarizations of the wave velocities. With the exception of C13, these values substantially agree with the data of Voigt and Bhimasenachar. ?? 1962 The American Institute of Physics.

  15. Algorithm for structure constants

    CERN Document Server

    Paiva, F M

    2011-01-01

    In a $n$-dimensional Lie algebra, random numerical values are assigned by computer to $n(n-1)$ especially selected structure constants. An algorithm is then created, which calculates without ambiguity the remaining constants, obeying the Jacobi conditions. Differently from others, this algorithm is suitable even for poor personal computer. ------------- En $n$-dimensia algebro de Lie, hazardaj numeraj valoroj estas asignitaj per komputilo al $n(n-1)$ speciale elektitaj konstantoj de strukturo. Tiam algoritmo estas kreita, kalkulante senambigue la ceterajn konstantojn, obeante kondicxojn de Jacobi. Malsimile al aliaj algoritmoj, tiu cxi tauxgas ecx por malpotenca komputilo.

  16. Radiographic constant exposure technique

    DEFF Research Database (Denmark)

    Domanus, Joseph Czeslaw

    1985-01-01

    The constant exposure technique has been applied to assess various industrial radiographic systems. Different X-ray films and radiographic papers of two producers were compared. Special attention was given to fast film and paper used with fluorometallic screens. Radiographic image quality...... was tested by the use of ISO wire IQI's and ASTM penetrameters used on Al and Fe test plates. Relative speed and reduction of kilovoltage obtained with the constant exposure technique were calculated. The advantages of fast radiographic systems are pointed out...

  17. The aliquot constant

    CERN Document Server

    Bosma, Wieb

    2009-01-01

    The average value of log s(n)/n taken over the first N even integers is shown to converge to a constant lambda when N tends to infinity; moreover, the value of this constant is approximated and proven to be less than 0. Here s(n) sums the divisors of n less than n. Thus the geometric mean of s(n)/n, the growth factor of the function s, in the long run tends to be less than 1. This could be interpreted as probabilistic evidence that aliquot sequences tend to remain bounded.

  18. Compassion is a constant.

    Science.gov (United States)

    Scott, Tricia

    2015-11-01

    Compassion is a powerful word that describes an intense feeling of commiseration and a desire to help those struck by misfortune. Most people know intuitively how and when to offer compassion to relieve another person's suffering. In health care, compassion is a constant; it cannot be rationed because emergency nurses have limited time or resources to manage increasing demands.

  19. Continued fractions constructed from prime numbers

    CERN Document Server

    Wolf, Marek

    2010-01-01

    We give 50 digits values of the simple continued fractions whose denominators are formed from a) prime numbers, b) twin primes, c) primes of the form m^2+1 and Mersenne primes. All these continued fractions belong to the set of measure zero of exceptions to the Khinchin Theorem.

  20. Fraction Reduction through Continued Fractions

    Science.gov (United States)

    Carley, Holly

    2011-01-01

    This article presents a method of reducing fractions without factoring. The ideas presented may be useful as a project for motivated students in an undergraduate number theory course. The discussion is related to the Euclidean Algorithm and its variations may lead to projects or early examples involving efficiency of an algorithm.

  1. On a discretization process of fractional-order Logistic differential equation

    National Research Council Canada - National Science Library

    El Raheem, Z.F; Salman, S.M

    2014-01-01

    .... First of all, we consider the fractional-order Logistic differential equation then, we consider the corresponding fractional-order Logistic differential equation with piecewise constant arguments...

  2. Constant envelope chirped OFDM power efficiency

    Science.gov (United States)

    Dida, Mussa A.; Hao, Huan; Anjum, M. R.; Ran, Tao

    2016-10-01

    Fractional Fourier OFDM or simply chirped OFDM performs better in time-frequency selective channel than its convectional OFDM. Although chirped OFDM outperforms OFDM it still inherits Peak to Average Power Ratio (PAPR) drawback as a convectional OFDM. To eliminate PAPR drawback Constant Envelope OFDM was developed and for better performance in time frequency selective channel Constant Envelope Fractional Fourier OFDM (CE-COFDM) is used. Its BER performance is analyzed and compared to chirped OFDM and OFDM in AWGN and Rayleigh channel. The simulations show the BER performance of CE-COFDM is the same as chirped OFDM and OFDM. The power efficiency of CE-COFDM is also studied and different simulations performed shows CE-COFDM is more power efficient than chirped OFDM and convectional OFDM for class A and class B Linear Power Amplifier (LPA).

  3. Variation of fundamental constants

    CERN Document Server

    Flambaum, V V

    2006-01-01

    We present a review of recent works devoted to the variation of the fine structure constant alpha, strong interaction and fundamental masses. There are some hints for the variation in quasar absorption spectra, Big Bang nucleosynthesis, and Oklo natural nuclear reactor data. A very promising method to search for the variation of the fundamental constants consists in comparison of different atomic clocks. Huge enhancement of the variation effects happens in transition between accidentally degenerate atomic and molecular energy levels. A new idea is to build a ``nuclear'' clock based on the ultraviolet transition between very low excited state and ground state in Thorium nucleus. This may allow to improve sensitivity to the variation up to 10 orders of magnitude! Huge enhancement of the variation effects is also possible in cold atomic and molecular collisions near Feschbach resonance.

  4. Constant-pressure Blowers

    Science.gov (United States)

    Sorensen, E

    1940-01-01

    The conventional axial blowers operate on the high-pressure principle. One drawback of this type of blower is the relatively low pressure head, which one attempts to overcome with axial blowers producing very high pressure at a given circumferential speed. The Schicht constant-pressure blower affords pressure ratios considerably higher than those of axial blowers of conventional design with approximately the same efficiency.

  5. String Scale Cosmological Constant

    OpenAIRE

    Chalmers, Gordon

    2006-01-01

    The cosmological constant is an unexplained until now phenomena of nature that requires an explanation through string effects. The apparent discrepancy between theory and experiment is enourmous and has already been explained several times by the author including mechanisms. In this work the string theory theory of abolished string modes is documented and given perturbatively to all loop orders. The holographic underpinning is also exposed. The matching with the data of the LIGO and D0 experi...

  6. The Hubble Constant.

    Science.gov (United States)

    Jackson, Neal

    2015-01-01

    I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H0 values of around 72-74 km s(-1) Mpc(-1), with typical errors of 2-3 km s(-1) Mpc(-1). This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67-68 km s(-1) Mpc(-1) and typical errors of 1-2 km s(-1) Mpc(-1). The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.

  7. Universe of constant

    Science.gov (United States)

    Yongquan, Han

    2016-10-01

    The ideal gas state equation is not applicable to ordinary gas, it should be applied to the Electromagnetic ``gas'' that is applied to the radiation, the radiation should be the ultimate state of matter changes or initial state, the universe is filled with radiation. That is, the ideal gas equation of state is suitable for the Singular point and the universe. Maybe someone consider that, there is no vessel can accommodate radiation, it is because the Ordinary container is too small to accommodate, if the radius of your container is the distance that Light through an hour, would you still think it can't accommodates radiation? Modern scientific determinate that the radius of the universe now is about 1027 m, assuming that the universe is a sphere whose volume is approximately: V = 4.19 × 1081 cubic meters, the temperature radiation of the universe (cosmic microwave background radiation temperature of the universe, should be the closest the average temperature of the universe) T = 3.15k, radiation pressure P = 5 × 10-6 N / m 2, according to the law of ideal gas state equation, PV / T = constant = 6 × 1075, the value of this constant is the universe, The singular point should also equal to the constant Author: hanyongquan

  8. The Hubble Constant

    Directory of Open Access Journals (Sweden)

    Neal Jackson

    2015-09-01

    Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. There are two broad categories of measurements. The first uses individual astrophysical objects which have some property that allows their intrinsic luminosity or size to be determined, or allows the determination of their distance by geometric means. The second category comprises the use of all-sky cosmic microwave background, or correlations between large samples of galaxies, to determine information about the geometry of the Universe and hence the Hubble constant, typically in a combination with other cosmological parameters. Many, but not all, object-based measurements give H_0 values of around 72–74 km s^–1 Mpc^–1, with typical errors of 2–3 km s^–1 Mpc^–1. This is in mild discrepancy with CMB-based measurements, in particular those from the Planck satellite, which give values of 67–68 km s^–1 Mpc^–1 and typical errors of 1–2 km s^–1 Mpc^–1. The size of the remaining systematics indicate that accuracy rather than precision is the remaining problem in a good determination of the Hubble constant. Whether a discrepancy exists, and whether new physics is needed to resolve it, depends on details of the systematics of the object-based methods, and also on the assumptions about other cosmological parameters and which datasets are combined in the case of the all-sky methods.

  9. Spaces of constant curvature

    CERN Document Server

    Wolf, Joseph A

    2010-01-01

    This book is the sixth edition of the classic Spaces of Constant Curvature, first published in 1967, with the previous (fifth) edition published in 1984. It illustrates the high degree of interplay between group theory and geometry. The reader will benefit from the very concise treatments of riemannian and pseudo-riemannian manifolds and their curvatures, of the representation theory of finite groups, and of indications of recent progress in discrete subgroups of Lie groups. Part I is a brief introduction to differentiable manifolds, covering spaces, and riemannian and pseudo-riemannian geomet

  10. Digital Preservation.

    Science.gov (United States)

    Yakel, Elizabeth

    2001-01-01

    Reviews research on digital preservation issues, including born-digital and digitally recreated documents. Discusses electronic records research; metadata and other standards; electronic mail; Web-based documents; moving images media; selection of materials for digitization, including primary sources; administrative issues; media stability…

  11. Representations of the magnitudes of fractions.

    Science.gov (United States)

    Schneider, Michael; Siegler, Robert S

    2010-10-01

    We tested whether adults can use integrated, analog, magnitude representations to compare the values of fractions. The only previous study on this question concluded that even college students cannot form such representations and instead compare fraction magnitudes by representing numerators and denominators as separate whole numbers. However, atypical characteristics of the presented fractions might have provoked the use of atypical comparison strategies in that study. In our 3 experiments, university and community college students compared more balanced sets of single-digit and multi-digit fractions and consistently exhibited a logarithmic distance effect. Thus, adults used integrated, analog representations, akin to a mental number line, to compare fraction magnitudes. We interpret differences between the past and present findings in terms of different stimuli eliciting different solution strategies.

  12. Fractional complex transforms for fractional differential equations

    National Research Council Canada - National Science Library

    Ibrahim, Rabha W

    2012-01-01

    The fractional complex transform is employed to convert fractional differential equations analytically in the sense of the Srivastava-Owa fractional operator and its generalization in the unit disk...

  13. The Hubble Constant

    Directory of Open Access Journals (Sweden)

    Jackson Neal

    2007-09-01

    Full Text Available I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. In the last 20 years, much progress has been made and estimates now range between 60 and 75 km s^-1 Mpc^-1, with most now between 70 and 75 km s^-1 Mpc^-1, a huge improvement over the factor-of-2 uncertainty which used to prevail. Further improvements which gave a generally agreed margin of error of a few percent rather than the current 10% would be vital input to much other interesting cosmology. There are several programmes which are likely to lead us to this point in the next 10 years.

  14. When constants are important

    Energy Technology Data Exchange (ETDEWEB)

    Beiu, V.

    1997-04-01

    In this paper the authors discuss several complexity aspects pertaining to neural networks, commonly known as the curse of dimensionality. The focus will be on: (1) size complexity and depth-size tradeoffs; (2) complexity of learning; and (3) precision and limited interconnectivity. Results have been obtained for each of these problems when dealt with separately, but few things are known as to the links among them. They start by presenting known results and try to establish connections between them. These show that they are facing very difficult problems--exponential growth in either space (i.e. precision and size) and/or time (i.e., learning and depth)--when resorting to neural networks for solving general problems. The paper will present a solution for lowering some constants, by playing on the depth-size tradeoff.

  15. Constant Proportion Portfolio Insurance

    DEFF Research Database (Denmark)

    Jessen, Cathrine

    2014-01-01

    Portfolio insurance, as practiced in 1987, consisted of trading between an underlying stock portfolio and cash, using option theory to place a floor on the value of the position, as if it included a protective put. Constant Proportion Portfolio Insurance (CPPI) is an option-free variation...... on the theme, originally proposed by Fischer Black. In CPPI, a financial institution guarantees a floor value for the “insured” portfolio and adjusts the stock/bond mix to produce a leveraged exposure to the risky assets, which depends on how far the portfolio value is above the floor. Plain-vanilla portfolio...... insurance largely died with the crash of 1987, but CPPI is still going strong. In the frictionless markets of finance theory, the issuer’s strategy to hedge its liability under the contract is clear, but in the real world with transactions costs and stochastic jump risk, the optimal strategy is less obvious...

  16. Decay constants in geochronology

    Institute of Scientific and Technical Information of China (English)

    IgorM.Villa; PaulR.Renne

    2005-01-01

    Geologic time is fundamental to the Earth Sciences, and progress in many disciplines depends critically on our ability to measure time with increasing accuracy and precision. Isotopic geochronology makes use of the decay of radioactive nuclides as a help to quantify the histories of rock, minerals, and other materials. Both accuracy and precision of radioisotopic ages are, at present, limited by those of radioactive decay constants. Modem mass spectrometers can measure isotope ratios with a precision of 10-4 or better. On the other hand, the uncertainties associated with direct half-life determinations are, in most cases, still at the percent level. The present short note briefly summarizes progress and problems that have been encountered during the Working Group's activity.

  17. Fractional complex transform for fractional differential equations

    National Research Council Canada - National Science Library

    Lİ, Zheng Biao; HE, Ji Huan

    2010-01-01

    Fractional complex transform is proposed to convert fractional differential equations into ordinary differential equations, so that all analytical methods devoted to advanced calculus can be easily...

  18. The fine structure constant and numerical alchemy

    CERN Document Server

    Dattoli, Giuseppe

    2010-01-01

    We comment on past and more recent efforts to derive a formula yielding the fine structure constant in terms of integers and transcendent numbers. We analyse these "exoteric" attitudes and describe the myths regarding {\\alpha}, which seems to have very ancient roots, tracing back to Cabbala and to medieval alchemic conceptions. We discuss the obsession for this constant developed by Pauli and the cultural "environment" in which such an "obsession" grew. We also derive a simple formula for {\\alpha} in terms of two numbers {\\pi} and 137 only. The formula we propose reproduces the experimental values up to the last significant digit, it has not any physical motivation and is the result of an alchemic combination of numbers. We make a comparison with other existing formulae, discuss the relevant limits of validity by comparison with the experimental values and discuss a criterion to recover a physical meaning, if existing, from their mathematical properties.

  19. Digital Culture and Digital Library

    Directory of Open Access Journals (Sweden)

    Yalçın Yalçınkaya

    2016-12-01

    Full Text Available In this study; digital culture and digital library which have a vital connection with each other are examined together. The content of the research consists of the interaction of culture, information, digital culture, intellectual technologies, and digital library concepts. The study is an entry work to integrity of digital culture and digital library theories and aims to expand the symmetry. The purpose of the study is to emphasize the relation between the digital culture and digital library theories acting intersection of the subjects that are examined. Also the perspective of the study is based on examining the literature and analytical evaluation in both studies (digital culture and digital library. Within this context, the methodology of the study is essentially descriptive and has an attribute for the transmission and synthesis of distributed findings produced in the field of the research. According to the findings of the study results, digital culture is an inclusive term that describes the effects of intellectual technologies in the field of information and communication. Information becomes energy and the spectrum of the information is expanding in the vertical rise through the digital culture. In this context, the digital library appears as a new living space of a new environment. In essence, the digital library is information-oriented; has intellectual technology support and digital platform; is in a digital format; combines information resources and tools in relationship/communication/cooperation by connectedness, and also it is the dynamic face of the digital culture in time and space independence. Resolved with the study is that the digital libraries are active and effective in the formation of global knowing and/or mass wisdom in the process of digital culture.

  20. Systematic harmonic power laws inter-relating multiple fundamental constants

    Science.gov (United States)

    Chakeres, Donald; Buckhanan, Wayne; Andrianarijaona, Vola

    2017-01-01

    Power laws and harmonic systems are ubiquitous in physics. We hypothesize that 2, π, the electron, Bohr radius, Rydberg constant, neutron, fine structure constant, Higgs boson, top quark, kaons, pions, muon, Tau, W, and Z when scaled in a common single unit are all inter-related by systematic harmonic powers laws. This implies that if the power law is known it is possible to derive a fundamental constant's scale in the absence of any direct experimental data of that constant. This is true for the case of the hydrogen constants. We created a power law search engine computer program that randomly generated possible positive or negative powers searching when the product of logical groups of constants equals 1, confirming they are physically valid. For 2, π, and the hydrogen constants the search engine found Planck's constant, Coulomb's energy law, and the kinetic energy law. The product of ratios defined by two constants each was the standard general format. The search engine found systematic resonant power laws based on partial harmonic fraction powers of the neutron for all of the constants with products near 1, within their known experimental precision, when utilized with appropriate hydrogen constants. We conclude that multiple fundamental constants are inter-related within a harmonic power law system.

  1. The Interacting and Non-constant Cosmological Constant

    CERN Document Server

    Verma, Murli Manohar

    2009-01-01

    We propose a time-varying cosmological constant with a fixed equation of state, which evolves mainly through its interaction with the background during most of the long history of the universe. However, such interaction does not exist in the very early and the late-time universe and produces the acceleration during these eras when it becomes very nearly a constant. It is found that after the initial inflationary phase, the cosmological constant, that we call as lambda parameter, rolls down from a large constant value to another but very small constant value and further dominates the present epoch showing up in form of the dark energy driving the acceleration.

  2. Quantum Theory without Planck's Constant

    CERN Document Server

    Ralston, John P

    2012-01-01

    Planck's constant was introduced as a fundamental scale in the early history of quantum mechanics. We find a modern approach where Planck's constant is absent: it is unobservable except as a constant of human convention. Despite long reference to experiment, review shows that Planck's constant cannot be obtained from the data of Ryberg, Davisson and Germer, Compton, or that used by Planck himself. In the new approach Planck's constant is tied to macroscopic conventions of Newtonian origin, which are dispensable. The precision of other fundamental constants is substantially improved by eliminating Planck's constant. The electron mass is determined about 67 times more precisely, and the unit of electric charge determined 139 times more precisely. Improvement in the experimental value of the fine structure constant allows new types of experiment to be compared towards finding "new physics." The long-standing goal of eliminating reliance on the artifact known as the International Prototype Kilogram can be accompl...

  3. Digital photography

    National Research Council Canada - National Science Library

    Windsor, J S; Rodway, G W; Middleton, P M; McCarthy, S

    2006-01-01

    The emergence of a new generation of "point-and-shoot" digital cameras offers doctors a compact, portable and user-friendly solution to the recording of highly detailed digital photographs and video images...

  4. Meadow based Fraction Theory

    OpenAIRE

    Bergstra, Jan A.

    2015-01-01

    In the context of an involutive meadow a precise definition of fractions is formulated and on that basis formal definitions of various classes of fractions are given. The definitions follow the fractions as terms paradigm. That paradigm is compared with two competing paradigms for storytelling on fractions: fractions as values and fractions as pairs.

  5. Digital Tectonics

    DEFF Research Database (Denmark)

    Christiansen, Karl; Borup, Ruben; Søndergaard, Asbjørn;

    2014-01-01

    Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated.......Digital Tectonics treats the architectonical possibilities in digital generation of form and production. The publication is the first volume of a series, in which aspects of the strategic focus areas of the Aarhus School of Architecture will be disseminated....

  6. Digital squares

    DEFF Research Database (Denmark)

    Forchhammer, Søren; Kim, Chul E

    1988-01-01

    Digital squares are defined and their geometric properties characterized. A linear time algorithm is presented that considers a convex digital region and determines whether or not it is a digital square. The algorithm also determines the range of the values of the parameter set of its preimages....... The analysis involves transforming the boundary of a digital region into parameter space of slope and y-intercept...

  7. Digital Citizenship

    Science.gov (United States)

    Isman, Aytekin; Canan Gungoren, Ozlem

    2014-01-01

    Era in which we live is known and referred as digital age.In this age technology is rapidly changed and developed. In light of these technological advances in 21st century, schools have the responsibility of training "digital citizen" as well as a good citizen. Digital citizens must have extensive skills, knowledge, Internet and …

  8. Oversampling analysis in fractional Fourier domain

    Institute of Scientific and Technical Information of China (English)

    ZHANG Feng; TAO Ran; WANG Yue

    2009-01-01

    Oversampling is widely used in practical applications of digital signal processing. As the fractional Fourier transform has been developed and applied in signal processing fields, it is necessary to consider the oversampling theorem in the fractional Fourier domain. In this paper, the oversampling theorem in the fractional Fourier domain is analyzed. The fractional Fourier spectral relation between the original oversampled sequence and its subsequences is derived first, and then the expression for exact reconstruction of the missing samples in terms of the subsequences is obtained. Moreover, by taking a chirp signal as an example, it is shown that, reconstruction of the missing samples in the oversampled signal Is suitable in the fractional Fourier domain for the signal whose time-frequency distribution has the minimum support in the fractional Fourier domain.

  9. Easy characterization of petroleum fractions: Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Miquel, J. (Univ. Politecnica de Catalunya (Spain)); Castells, F. (Univ. Rovira i Virgili, Catalunya (Spain))

    1993-12-01

    A new method for characterizing petroleum fractions, based on pseudocomponent breakdown using the integral method has been developed. It requires only that one has an atmospheric true boiling point (tbp) distillation curve and known the entire fraction density. The proposed characterization procedure is valid for representing any oil fraction (light or heavy) with a boiling point range smaller than 300 K. It is based on the hypothesis of constant Watson's characterization factor, K[sub w], for all the pseudocomponents. Outside this range, it is less accurate (greater errors in material and molar balances). Therefore, a method considering the variable K[sub w] is best to treat these fractions.

  10. Digital preservation

    CERN Document Server

    Deegan, Marilyn

    2013-01-01

    Digital preservation is an issue of huge importance to the library and information profession right now. With the widescale adoption of the internet and the rise of the world wide web, the world has been overwhelmed by digital information. Digital data is being produced on a massive scale by individuals and institutions: some of it is born, lives and dies only in digital form, and it is the potential death of this data, with its impact on the preservation of culture, that is the concern of this book. So how can information professionals try to remedy this? Digital preservation is a complex iss

  11. Digital subtraktion

    DEFF Research Database (Denmark)

    Mussmann, Bo Redder

    2004-01-01

    Digital subtraktion er en metode til at fjerne uønskede oplysninger i et røntgenbillede. Subtraktionsteknikken bruges primært i forbindelse med angiografi hvor man kun er interesseret i at se selve karret. Derfor er digital subtraktion i daglig tale synonymt med DSA eller DVI – hhv. Digital...... Subtraction Angiography eller Digital Vascular Imaging. Benævnelserne er to røntgenfirmaers navn for den samme teknik. Digital subtraktion kræver speciel software, samt at apparaturet kan eksponere i serier....

  12. Digital Natives or Digital Tribes?

    Science.gov (United States)

    Watson, Ian Robert

    2013-01-01

    This research builds upon the discourse surrounding digital natives. A literature review into the digital native phenomena was undertaken and found that researchers are beginning to identify the digital native as not one cohesive group but of individuals influenced by other factors. Primary research by means of questionnaire survey of technologies…

  13. Statistical Modelling of the Soil Dielectric Constant

    Science.gov (United States)

    Usowicz, Boguslaw; Marczewski, Wojciech; Bogdan Usowicz, Jerzy; Lipiec, Jerzy

    2010-05-01

    The dielectric constant of soil is the physical property being very sensitive on water content. It funds several electrical measurement techniques for determining the water content by means of direct (TDR, FDR, and others related to effects of electrical conductance and/or capacitance) and indirect RS (Remote Sensing) methods. The work is devoted to a particular statistical manner of modelling the dielectric constant as the property accounting a wide range of specific soil composition, porosity, and mass density, within the unsaturated water content. Usually, similar models are determined for few particular soil types, and changing the soil type one needs switching the model on another type or to adjust it by parametrization of soil compounds. Therefore, it is difficult comparing and referring results between models. The presented model was developed for a generic representation of soil being a hypothetical mixture of spheres, each representing a soil fraction, in its proper phase state. The model generates a serial-parallel mesh of conductive and capacitive paths, which is analysed for a total conductive or capacitive property. The model was firstly developed to determine the thermal conductivity property, and now it is extended on the dielectric constant by analysing the capacitive mesh. The analysis is provided by statistical means obeying physical laws related to the serial-parallel branching of the representative electrical mesh. Physical relevance of the analysis is established electrically, but the definition of the electrical mesh is controlled statistically by parametrization of compound fractions, by determining the number of representative spheres per unitary volume per fraction, and by determining the number of fractions. That way the model is capable covering properties of nearly all possible soil types, all phase states within recognition of the Lorenz and Knudsen conditions. In effect the model allows on generating a hypothetical representative of

  14. Digital Feedback: Trends in Constituents\\' Communication with Elected Officials

    OpenAIRE

    Hickey, Chelsea Aleena

    2013-01-01

    Individuals born after 1980 are often immediately labeled with the term, "digital generation". This label assumes that young people are fluent, proficient, and constant users of digital media. This thesis explores digital communication behavior in the context of political communication. This thesis begins with an exploration of how age influences digital political communication, finding that while young people prefer digital media more so than older generations, they are less likely to utiliz...

  15. Fraction Photo Frenzy: A New Exploration

    Science.gov (United States)

    Canada, Daniel L.

    2009-01-01

    This article relates how a class of elementary preservice teachers used technology to share their thinking about a topic that is traditionally difficult to model and discuss--dividing fractions. One type of technology they used, a digital camera, was familiar to most students, but the other type, a SMART Board[TM], was relatively unfamiliar.…

  16. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    , by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research......This dissertation forwards the theory of digital consumer-response as a perspective to examine how digital media practices influence consumers’ response to advertising. Digital consumer-response is a development of advertising theory that encompasses how consumers employ their knowledge...... and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising...

  17. The fractional oscillator process with two indices

    Energy Technology Data Exchange (ETDEWEB)

    Lim, S C [Faculty of Engineering, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia); Teo, L P [Faculty of Information Technology, Multimedia University, Jalan Multimedia, Cyberjaya 63100, Selangor Darul Ehsan (Malaysia)], E-mail: sclim@mmu.edu.my, E-mail: lpteo@mmu.edu.my

    2009-02-13

    We introduce a new fractional oscillator process which can be obtained as a solution of a stochastic differential equation with two fractional orders. Basic properties such as fractal dimension and short-range dependence of the process are studied by considering the asymptotic properties of its covariance function. By considering the fractional oscillator process as the velocity of a diffusion process, we derive the corresponding diffusion constant, fluctuation-dissipation relation and mean-square displacement. The fractional oscillator process can also be regarded as a one-dimensional fractional Euclidean Klein-Gordon field, which can be obtained by applying the Parisi-Wu stochastic quantization method to a nonlocal Euclidean action. The Casimir energy associated with the fractional field at positive temperature is calculated by using the zeta function regularization technique.

  18. Digital Forensics

    OpenAIRE

    Ψευτέλης, Αθανάσιος Δημήτρης

    2013-01-01

    A reprint from American Scientist the magazine of Sigma Xi, The Scientific Research Society Since the 1980s, computers have had increasing roles in all aspects of human life—including an involvement in criminal acts. This development has led to the rise of digital forensics, the uncovering and examination of evidence located on all things electronic with digital storage, including computers, cell phones, and networks. Digital forensics researchers and practitione...

  19. Measurable values, numbers and fundamental physical constants: Is the Boltzmann constant Kb a fundamental physical constant?

    Directory of Open Access Journals (Sweden)

    Bormashenko Edward

    2009-01-01

    Full Text Available The status of fundamental physical constants is discussed. The nature of fundamental physical constants is cleared up, based on the analysis of the Boltzmann constant. A new definition of measurable values, 'mathematical' and 'physical' numbers and fundamental physical constants is proposed. Mathematical numbers are defined as values insensitive to the choice of both units and frames of reference, whereas 'physical numbers' are dimensionless values, insensitive to transformations of units and sensitive to the transformations of the frames of reference. Fundamental constants are classified as values sensitive to transformations of the units and insensitive to transformations of the frames of reference. It is supposed that a fundamental physical constant necessarily allows diminishing the number of independent etalons in a system of units.

  20. Digital printing

    Science.gov (United States)

    Sobotka, Werner K.

    1997-02-01

    Digital printing is described as a tool to replace conventional printing machines completely. Still this goal was not reached until now with any of the digital printing technologies to be described in the paper. Productivity and costs are still the main parameters and are not really solved until now. Quality in digital printing is no problem anymore. Definition of digital printing is to transfer digital datas directly on the paper surface. This step can be carried out directly or with the use of an intermediate image carrier. Keywords in digital printing are: computer- to-press; erasable image carrier; image carrier with memory. Digital printing is also the logical development of the new digital area as it is pointed out in Nicholas Negropotes book 'Being Digital' and also the answer to networking and Internet technologies. Creating images text and color in one country and publishing the datas in another country or continent is the main advantage. Printing on demand another big advantage and last but not least personalization the last big advantage. Costs and being able to coop with this new world of prepress technology is the biggest disadvantage. Therefore the very optimistic growth rates for the next few years are really nonexistent. The development of complete new markets is too slow and the replacing of old markets is too small.

  1. Digital displacements

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2014-01-01

    In recent years digital reforms are being introduced in the municipal landscape of Denmark. The reforms address the interaction between citizen and local authority. The aim is, that by 2015 at least 80 per cent of all correspondence between citizens and public authority will be transmitted through...... digital interface. However, the transformation of citizen services from traditional face-to-face interaction to digital self-service gives rise to new practices; some citizens need support to be able to manage self-service through digital tools. A mixture of support and teaching, named co...

  2. Matrix fractional systems

    Science.gov (United States)

    Tenreiro Machado, J. A.

    2015-08-01

    This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.

  3. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    2016-01-01

    Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charg...

  4. Constant-Pressure Hydraulic Pump

    Science.gov (United States)

    Galloway, C. W.

    1982-01-01

    Constant output pressure in gas-driven hydraulic pump would be assured in new design for gas-to-hydraulic power converter. With a force-multiplying ring attached to gas piston, expanding gas would apply constant force on hydraulic piston even though gas pressure drops. As a result, pressure of hydraulic fluid remains steady, and power output of the pump does not vary.

  5. Spectrophotometric determination of association constant

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2016-01-01

    Least-squares 'Systematic Trial-and-Error Procedure' (STEP) for spectrophotometric evaluation of association constant (equilibrium constant) K and molar absorption coefficient E for a 1:1 molecular complex, A + B = C, with error analysis according to Conrow et al. (1964). An analysis of the Charge...

  6. Nonminimal coupling and the cosmological constant problem

    CERN Document Server

    Glavan, Dražen

    2015-01-01

    We consider a universe with a positive effective cosmological constant and a nonminimally coupled scalar field. When the coupling constant is negative, the scalar field exhibits linear growth at asymptotically late times, resulting in a decaying effective cosmological constant. The Hubble rate in the Jordan frame reaches a self-similar solution, $H=1/(\\epsilon t)$, where the principal slow roll parameter $\\epsilon$ depends on $\\xi$, reaching maximally $\\epsilon=2$ (radiation era scaling) in the limit when $\\xi\\rightarrow -\\infty$. Similar results are found in the Einstein frame (E), with $H_E=1/(\\epsilon_E t)$, but now $\\epsilon_E \\rightarrow 4/3$ as $\\xi\\rightarrow -\\infty$. Therefore in the presence of a nonminimally coupled scalar de Sitter is not any more an attractor, but instead (when $\\xi4/3$ at a rate $\\Gamma\\gg H$, the scaling changes to that of matter, $\\epsilon\\rightarrow \\epsilon_m$, and the energy density in the effective cosmological becomes a fixed fraction of the matter energy density, $M_{\\rm...

  7. Digital Model of Railway Electric Traction Lines

    Science.gov (United States)

    Garg, Rachana; Mahajan, Priya; Kumar, Parmod

    2016-08-01

    The characteristic impedance and propagation constant define the behavior of signal propagation over the transmission lines. The digital model for railway traction lines which includes railway tracks is developed, using curve fitting technique in MATLAB. The sensitivity of this model has been computed with respect to frequency. The digital sensitivity values are compared with the values of analog sensitivity. The developed model is useful for digital protection, integrated operation, control and planning of the system.

  8. Digital Model of Railway Electric Traction Lines

    Science.gov (United States)

    Garg, Rachana; Mahajan, Priya; Kumar, Parmod

    2017-08-01

    The characteristic impedance and propagation constant define the behavior of signal propagation over the transmission lines. The digital model for railway traction lines which includes railway tracks is developed, using curve fitting technique in MATLAB. The sensitivity of this model has been computed with respect to frequency. The digital sensitivity values are compared with the values of analog sensitivity. The developed model is useful for digital protection, integrated operation, control and planning of the system.

  9. Calculation of individual isotope equilibrium constants for geochemical reactions

    Science.gov (United States)

    Thorstenson, D.C.; Parkhurst, D.L.

    2004-01-01

    Theory is derived from the work of Urey (Urey H. C. [1947] The thermodynamic properties of isotopic substances. J. Chem. Soc. 562-581) to calculate equilibrium constants commonly used in geochemical equilibrium and reaction-transport models for reactions of individual isotopic species. Urey showed that equilibrium constants of isotope exchange reactions for molecules that contain two or more atoms of the same element in equivalent positions are related to isotope fractionation factors by ?? = (Kex)1/n, where n is the number of atoms exchanged. This relation is extended to include species containing multiple isotopes, for example 13C16O18O and 1H2H18O. The equilibrium constants of the isotope exchange reactions can be expressed as ratios of individual isotope equilibrium constants for geochemical reactions. Knowledge of the equilibrium constant for the dominant isotopic species can then be used to calculate the individual isotope equilibrium constants. Individual isotope equilibrium constants are calculated for the reaction CO2g = CO2aq for all species that can be formed from 12C, 13C, 16O, and 18O; for the reaction between 12C18 O2aq and 1H218Ol; and among the various 1H, 2H, 16O, and 18O species of H2O. This is a subset of a larger number of equilibrium constants calculated elsewhere (Thorstenson D. C. and Parkhurst D. L. [2002] Calculation of individual isotope equilibrium constants for implementation in geochemical models. Water-Resources Investigation Report 02-4172. U.S. Geological Survey). Activity coefficients, activity-concentration conventions for the isotopic variants of H2O in the solvent 1H216Ol, and salt effects on isotope fractionation have been included in the derivations. The effects of nonideality are small because of the chemical similarity of different isotopic species of the same molecule or ion. The temperature dependence of the individual isotope equilibrium constants can be calculated from the temperature dependence of the fractionation

  10. Digital Libraries

    CERN Document Server

    Papy, Fabrice

    2008-01-01

    Of vital interest to all librarians and information specialists, this book presents all aspects of the effects of digitization of today's and tomorrow's libraries. From social to technical issues, Digital Libraries includes chapters on the growth of the role of librarian, the reader experience, cataloging, search engines, OPAC, law, ergonomic studies, and the future of libraries.

  11. Digital Audiobooks:

    DEFF Research Database (Denmark)

    Have, Iben; Pedersen, Birgitte Stougaard

    Audiobooks are rapidly gaining popularity with widely accessible digital downloading and streaming services. The paper is framing how the digital audiobook expands and changes the target groups for book publications and how it as an everyday activity is creating new reading experiences, places...

  12. Initialized Fractional Calculus

    Science.gov (United States)

    Lorenzo, Carl F.; Hartley, Tom T.

    2000-01-01

    This paper demonstrates the need for a nonconstant initialization for the fractional calculus and establishes a basic definition set for the initialized fractional differintegral. This definition set allows the formalization of an initialized fractional calculus. Two basis calculi are considered; the Riemann-Liouville and the Grunwald fractional calculi. Two forms of initialization, terminal and side are developed.

  13. DETERMINATION OF STABILITY CONSTANTS OF MANGANESE (II ...

    African Journals Online (AJOL)

    DR. AMINU

    Keywords: Amino acids, dissociation constant, potentiometry, stability constant. INTRODUCTION ... constants of manganese (II) amino acid complexes using potentiometer. .... Principles of Biochemistry Third Edition,. Worth publishers, 41 ...

  14. Varying constants, Gravitation and Cosmology

    CERN Document Server

    Uzan, Jean-Philippe

    2010-01-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describ...

  15. Ruzsa's Constant on Additive Functions

    Institute of Scientific and Technical Information of China (English)

    Jin Hui FANG; Yong Gao CHEN

    2013-01-01

    A function f:N → R is called additive if f(mn) =f(m)+f(n) for all m,n with (m,n) =1.Let μ(x) =maxn≤x(f(n)-f(n + 1)) and v(x) =maxn≤x(f(n + 1)-f(n)).In 1979,Ruzsa proved that there exists a constant c such that for any additive function f,μ(x) ≤ cv(x2) + cf,where cf is a constant depending only on f.Denote by Raf the least such constant c.We call Raf Ruzsa's constant on additive functions.In this paper,we prove that Raf ≤ 20.

  16. Naturally Time Dependent Cosmological Constant

    CERN Document Server

    Gregori, A

    2004-01-01

    In the light of the proposal of hep-th/0207195, we discuss in detail the issue of the cosmological constant, explaining how can string theory naturally predict the value which is experimentally observed, without low-energy supersymmetry.

  17. Inflation and the cosmological constant

    Directory of Open Access Journals (Sweden)

    FENG Chaojun

    2014-08-01

    Full Text Available By assuming the cosmological “constant” is no longer a constant during the inflation epoch,it is found that the cosmological constant fine-tuning problem is solved.In the meanwhile,inflation models could predict a large tensor-to-scalar ratio,correct power spectral index and a larger running of it.Furthermore,the e-folding number is large enough to overcome the horizon,flatness problems in the Big Bang cosmology.

  18. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  19. Varying Constants, Gravitation and Cosmology.

    Science.gov (United States)

    Uzan, Jean-Philippe

    2011-01-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  20. Varying Constants, Gravitation and Cosmology

    Science.gov (United States)

    Uzan, Jean-Philippe

    2011-12-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  1. Fractional Partial Differential Equation: Fractional Total Variation and Fractional Steepest Descent Approach-Based Multiscale Denoising Model for Texture Image

    Directory of Open Access Journals (Sweden)

    Yi-Fei Pu

    2013-01-01

    Full Text Available The traditional integer-order partial differential equation-based image denoising approaches often blur the edge and complex texture detail; thus, their denoising effects for texture image are not very good. To solve the problem, a fractional partial differential equation-based denoising model for texture image is proposed, which applies a novel mathematical method—fractional calculus to image processing from the view of system evolution. We know from previous studies that fractional-order calculus has some unique properties comparing to integer-order differential calculus that it can nonlinearly enhance complex texture detail during the digital image processing. The goal of the proposed model is to overcome the problems mentioned above by using the properties of fractional differential calculus. It extended traditional integer-order equation to a fractional order and proposed the fractional Green’s formula and the fractional Euler-Lagrange formula for two-dimensional image processing, and then a fractional partial differential equation based denoising model was proposed. The experimental results prove that the abilities of the proposed denoising model to preserve the high-frequency edge and complex texture information are obviously superior to those of traditional integral based algorithms, especially for texture detail rich images.

  2. Dielectric constant of liquid alkanes and hydrocarbon mixtures

    Science.gov (United States)

    Sen, A. D.; Anicich, V. G.; Arakelian, T.

    1992-01-01

    The complex dielectric constants of n-alkanes with two to seven carbon atoms have been measured. The measurements were conducted using a slotted-line technique at 1.2 GHz and at atmospheric pressure. The temperature was varied from the melting point to the boiling point of the respective alkanes. The real part of the dielectric constant was found to decrease with increasing temperature and correlate with the change in the molar volume. An upper limit to all the loss tangents was established at 0.001. The complex dielectric constants of a few mixtures of liquid alkanes were also measured at room temperature. For a pentane-octane mixture the real part of the dielectric constant could be explained by the Clausius-Mosotti theory. For the mixtures of n-hexane-ethylacetate and n-hexane-acetone the real part of the dielectric constants could be explained by the Onsager theory extended to mixtures. The dielectric constant of the n-hexane-acetone mixture displayed deviations from the Onsager theory at the highest fractions of acetone. The dipole moments of ethylacetate and acetone were determined for dilute mixtures using the Onsager theory and were found to be in agreement with their accepted gas-phase values. The loss tangents of the mixtures exhibited a linear relationship with the volume fraction for low concentrations of the polar liquids.

  3. Digitized Heat Transfer

    Science.gov (United States)

    Mohseni, Kamran; Young, Patrick

    2007-11-01

    This presentation presents theoretical and numerical results describing digitized heat transfer (DHT), an active thermal management technique for high-power electronics and integrated micro systems. In digitized heat transfer discrete droplets are employed. The internal flow inside a discrete droplet is dominated by internal circulation imposed by the boundaries. This internal circulation imposes a new timescale for recirculating cold liquid from the middle of the droplet to the boundary. This internal circulation produces periodic oscillation in the overall convective heat transfer rate. Numerical simulations are presented for heat transfer in the droplet for both constant temperature and flux boundary conditions. The effectiveness of DHT for managing both localized temperature spikes and steady state cooling is demonstrated, identifying key parameters for optimization of the DHT method.

  4. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    . With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills.......Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media...

  5. Digital holography

    CERN Document Server

    Picart, Pascal

    2013-01-01

    This book presents a substantial description of the principles and applications of digital holography.The first part of the book deals with mathematical basics and the linear filtering theory necessary to approach the topic. The next part describes the fundamentals of diffraction theory and exhaustively details the numerical computation of diffracted fields using FFT algorithms. A thorough presentation of the principles of holography and digital holography, including digital color holography, is proposed in the third part.A special section is devoted to the algorithms and method

  6. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  7. DIGITAL ASSESSMENTS

    OpenAIRE

    Nielsen, Kurt Gammelgaard; Petersen, Lise

    2013-01-01

    In accordance with The Danish eGOVERNMENT strategy 2011-2015 digital assessment and exam should be implemented at all Danish universities by the end of 2013. University of Southern Denmark (SDU) decided to start the implementation in May 2010.By the exam term of January 2013, the implementation proved successful, and close to completion. The majority of assessments at all of the 5 faculties and 5 campuses were digital, and students had handed in a total of 17.021 digital assessments.On the ba...

  8. Digital Leadership

    DEFF Research Database (Denmark)

    Zupancic, Tadeja; Verbeke, Johan; Achten, Henri

    2016-01-01

    Leadership is an important quality in organisations. Leadership is needed to introduce change and innovation. In our opinion, in architectural and design practices, the role of leadership has not yet been sufficiently studied, especially when it comes to the role of digital tools and media....... With this paper we intend to initiate a discussion in the eCAADe community to reflect and develop ideas in order to develop digital leadership skills amongst the membership. This paper introduces some important aspects, which may be valuable to look into when developing digital leadership skills....

  9. Digital Insights

    DEFF Research Database (Denmark)

    Knudsen, Gry Høngsmark

    and practices with digital media, when they meet and interpret advertising. Through studies of advertising response on YouTube and experiments with consumers’ response to digitally manipulated images, the dissertation shows how digital media practices facilitate polysemic and socially embedded advertising......, by incorporating media as both channel, frame, and apparatus for advertising response, the dissertation brings into attention that more aspects than the text-reader relationship influence ad response. Finally, the dissertation proposes the assemblage approach for exploring big data in consumer culture research...

  10. Measurements of timing resolution of ultra-fast silicon detectors with the SAMPIC waveform digitizer

    Science.gov (United States)

    Breton, D.; De Cacqueray, V.; Delagnes, E.; Grabas, H.; Maalmi, J.; Minafra, N.; Royon, C.; Saimpert, M.

    2016-11-01

    The SAMpler for PICosecond time (SAMPIC) chip has been designed by a collaboration including CEA/IRFU/SEDI, Saclay and CNRS/LAL/SERDI, Orsay. It benefits from both the quick response of a time to digital converter and the versatility of a waveform digitizer to perform accurate timing measurements. Thanks to the sampled signals, smart algorithms making best use of the pulse shape can be used to improve time resolution. A software framework has been developed to analyse the SAMPIC output data and extract timing information by using either a constant fraction discriminator or a fast cross-correlation algorithm. SAMPIC timing capabilities together with the software framework have been tested using pulses generated by a signal generator or by a silicon detector illuminated by a pulsed infrared laser. Under these ideal experimental conditions, the SAMPIC chip has proven to be capable of timing resolutions down to 4 ps with synthesized signals and 40 ps with silicon detector signals.

  11. α-bandlimited diffuser in fractional Fourier optics

    Science.gov (United States)

    Patiño-Vanegas, Alberto; Durand, Pierre-Emmanuel; Torres, Rafael; Pellat-Finet, Pierre

    2016-04-01

    We propose a method for calculating appropriate α-band limited diffusers using the fractional Fourier transform. In order to do this, we implement a method for performing a numerical interpolation in the fractional Fourier domain. Such diffusers with compact support in the Fresnel regime may be used in fractional Fourier optical systems where the use of diffusers produce speckles, e.g. digital holography or optical encryption. Numerical simulations are presented.

  12. Fraction Sense: Foundational Understandings.

    Science.gov (United States)

    Fennell, Francis Skip; Karp, Karen

    2016-08-09

    The intent of this commentary is to identify elements of fraction sense and note how the research studies provided in this special issue, in related but somewhat different ways, validate the importance of such understandings. Proficiency with fractions serves as a prerequisite for student success in higher level mathematics, as well as serving as a gateway to many occupations and varied contexts beyond the mathematics classroom. Fraction sense is developed through instructional opportunities involving fraction equivalence and magnitude, comparing and ordering fractions, using fraction benchmarks, and computational estimation. Such foundations are then extended to operations involving fractions and decimals and applications involving proportional reasoning. These components of fraction sense are all addressed in the studies provided in this issue, with particular consideration devoted to the significant importance of the use of the number line as a central representational tool for conceptually understanding fraction magnitude.

  13. Learning Read-constant Polynomials of Constant Degree modulo Composites

    DEFF Research Database (Denmark)

    Chattopadhyay, Arkadev; Gavaldá, Richard; Hansen, Kristoffer Arnsfelt;

    2011-01-01

    Boolean functions that have constant degree polynomial representation over a fixed finite ring form a natural and strict subclass of the complexity class \\textACC0ACC0. They are also precisely the functions computable efficiently by programs over fixed and finite nilpotent groups. This class...... is not known to be learnable in any reasonable learning model. In this paper, we provide a deterministic polynomial time algorithm for learning Boolean functions represented by polynomials of constant degree over arbitrary finite rings from membership queries, with the additional constraint that each variable...

  14. Effective cosmological constant induced by stochastic fluctuations of Newton's constant

    Science.gov (United States)

    de Cesare, Marco; Lizzi, Fedele; Sakellariadou, Mairi

    2016-09-01

    We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.

  15. Effective cosmological constant induced by stochastic fluctuations of Newton's constant

    CERN Document Server

    de Cesare, Marco; Sakellariadou, Mairi

    2016-01-01

    We consider implications of the microscopic dynamics of spacetime for the evolution of cosmological models. We argue that quantum geometry effects may lead to stochastic fluctuations of the gravitational constant, which is thus considered as a macroscopic effective dynamical quantity. Consistency with Riemannian geometry entails the presence of a time-dependent dark energy term in the modified field equations, which can be expressed in terms of the dynamical gravitational constant. We suggest that the late-time accelerated expansion of the Universe may be ascribed to quantum fluctuations in the geometry of spacetime rather than the vacuum energy from the matter sector.

  16. Digital fabrication

    CERN Document Server

    2012-01-01

    The Winter 2012 (vol. 14 no. 3) issue of the Nexus Network Journal features seven original papers dedicated to the theme “Digital Fabrication”. Digital fabrication is changing architecture in fundamental ways in every phase, from concept to artifact. Projects growing out of research in digital fabrication are dependent on software that is entirely surface-oriented in its underlying mathematics. Decisions made during design, prototyping, fabrication and assembly rely on codes, scripts, parameters, operating systems and software, creating the need for teams with multidisciplinary expertise and different skills, from IT to architecture, design, material engineering, and mathematics, among others The papers grew out of a Lisbon symposium hosted by the ISCTE-Instituto Universitario de Lisboa entitled “Digital Fabrication – A State of the Art”. The issue is completed with four other research papers which address different mathematical instruments applied to architecture, including geometric tracing system...

  17. Digital Humanities

    DEFF Research Database (Denmark)

    Brügger, Niels

    2016-01-01

    the humanities for decades, starting with research fields such as humanities computing or computational linguistics in the 1950s, and later new media studies and internet studies. The historical development of digital humanities has been characterized by a focus on three successive, but co-existing types......Digital humanities is an umbrella term for theories, methodologies, and practices related to humanities scholarship that use the digital computer as an integrated and essential part of its research and teaching activities. The computer can be used for establishing, finding, collecting......, and preserving material to study, as an object of study in its own right, as an analytical tool, or for collaborating, and for disseminating results. The term "digital humanities" was coined around 2001, and gained currency within academia in the following years. However, computers had been used within...

  18. Digital Snaps

    DEFF Research Database (Denmark)

    Sandbye, Mette; Larsen, Jonas

    The New Face of Snapshot Photography / Jonas Larsen and Mette Sandbye -- pt. I. IMAGES ON WEB 2.0 AND THE CAMERA PHONE -- ch. 1. Overlooking, Rarely Looking and Not Looking / Martin Lister -- ch. 2. The (Im)mobile Life of Digital Photographs: The Case of Tourist Photography / Jonas Larsen -- ch. 3....... Distance as the New Punctum / Mikko Villi -- pt. II. FAMILY ALBUMS IN TRANSITION -- ch. 4. How Digital Technologies Do Family Snaps, Only Better / Gillian Rose -- ch. 5. Friendship Photography: Memory, Mobility and Social Networking / Joanne Garde-Hansen -- ch. 6. Play, Process and Materiality in Japanese...... Purikura Photography / Mette Sandbye -- ch. 7. 'Buying an Instrument Does Not Necessarily Make You a Musician': Studio Photography and the Digital Revolution / Sigrid Lien -- pt. III. NEW PUBLIC FORMS -- ch. 8 Paparazzi Photography, Seriality and the Digital Photo Archive / Anne Jerslev and Mette Mortensen...

  19. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    The purpose of this paper is to examine the impact of e-government reforms on street-level bureaucrats’ professionalism and relation to citizens, thus demonstrating how the bureaucratic encounter unfolds in the digital era. Design/methodology/approach: The paper is based on an ethnographic study....... An ethnographic account of how digital reforms are implemented in practice shows how street-level bureaucrat’s classic tasks such as specialized casework are being reconfigured into educational tasks that promote the idea of “becoming digital”. In the paper, the author argues that the work of “becoming digital....... Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...

  20. Digital Steganography

    OpenAIRE

    KOCIÁNOVÁ, Helena

    2009-01-01

    Digital steganography is a technique for hiding data mostly into multimedia files (images, audio, video). With the development of information technology this technique has found its use in the field of copyright protection and secret data transfer, could be even applied in places where is limited possibility of using cryptography (e. g. by law). This thesis gives insight into digital steganography and contains an application using this technique.

  1. Digital watermark

    OpenAIRE

    Jasna Maver

    2004-01-01

    The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to diffe...

  2. From the Rydberg constant to the fundamental constants metrology; De la constante de Rydberg a la metrologie des constantes fondamentales

    Energy Technology Data Exchange (ETDEWEB)

    Nez, F

    2005-06-15

    This document reviews the theoretical and experimental achievements of the author since the beginning of his scientific career. This document is dedicated to the spectroscopy of hydrogen, deuterium and helium atoms. The first part is divided into 6 sub-sections: 1) the principles of hydrogen spectroscopy, 2) the measurement of the 2S-nS/nD transitions, 3) other optical frequency measurements, 4) our contribution to the determination of the Rydberg constant, 5) our current experiment on the 1S-3S transition, 6) the spectroscopy of the muonic hydrogen. Our experiments have improved the accuracy of the Rydberg Constant by a factor 25 in 15 years and we have achieved the first absolute optical frequency measurement of a transition in hydrogen. The second part is dedicated to the measurement of the fine structure constant and the last part deals with helium spectroscopy and the search for optical references in the near infrared range. (A.C.)

  3. Mirror QCD and Cosmological Constant

    CERN Document Server

    Pasechnik, Roman; Teryaev, Oleg

    2016-01-01

    An analog of Quantum Chromo Dynamics (QCD) sector known as mirror QCD (mQCD) can affect the cosmological evolution and help in resolving the Cosmological Constant problem. In this work, we explore an intriguing possibility for a compensation of the negative QCD vacuum contribution to the ground state energy density of the universe by means of a positive contribution from the chromomagnetic gluon condensate in mQCD. The trace anomaly compensation condition and the form of the mQCD coupling constant in the infrared limit have been proposed by analysing a partial non-perturbative solution of the Einstein--Yang-Mills equations of motion.

  4. Spatial Variations of Fundamental Constants

    CERN Document Server

    Barrow, John D; Barrow, John D.; Toole, Chris O'

    1999-01-01

    We show that observational limits on the possible time variation of constants of Nature are significantly affected by allowing for both space and time variation. Bekenstein's generalisation of Maxwell's equations to allow for cosmological variation of $alpha$ is investigated in a universe containing spherically symmetric inhomogeneities. The time variation of $alpha$ is determined by the local matter density and hence limits obtained in high-density geophysical enviroments are far more constraining than those obtained at high redshift. This new feature is expected to be a property of a wide class of theories for the variation of constants.

  5. Bouncing universes with varying constants

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, John D [DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Kimberly, Dagny [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom); Magueijo, Joao [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom)

    2004-09-21

    We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where G also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.

  6. Bouncing Universes with Varying Constants

    CERN Document Server

    Barrow, J D; Magueijo, J; Barrow, John D.; Kimberly, Dagny; Magueijo, Joao

    2004-01-01

    We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying-alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where $G$ also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.

  7. Gravitational Instantons and Cosmological Constant

    CERN Document Server

    Cyriac, Josily

    2015-01-01

    The cosmological dynamics of an otherwise empty universe in the presence of vacuum fields is considered. Quantum fluctuations at the Planck scale leads to a dynamical topology of space-time at very small length scales, which is dominated by compact gravitational instantons. The Planck scale vacuum energy acts as a source for the curvature of the these compact gravitational instantons and decouples from the large scale energy momentum tensor of the universe, thus making the observable cosmological constant vanish. However, a Euclidean functional integral over all possible topologies of the gravitational instantons generates a small non-zero value for the large scale cosmological constant, which agrees with the present observations.

  8. Meaning of Fractions

    Science.gov (United States)

    Dewi, D. A. K.; Suryadi, D.; Suratno, T.; Mulyana, E.; Kurniawan, H.

    2017-02-01

    Introducing fractions is identical to divide an object. Suppose we divide the apple into two parts. One divided into two parts, the question arises whether one part can be called a half or not. Based on this activity, how can students give meaning to fractions. This study aims at designing a different fractions lesson by applying Didactical Design Research. In doing so, we undertook several research phases: 1) thinking what is fractions and why students should learn this concept; 2) designing didactical situation based on identified learning obstacles; and 3) reflecting retrospectively on the lesson design and its implementation as to redesign the fractions lesson. Our analysis revealed that most students held epistemological obstacles in giving meaning of fractions because they only know fractions as numbers that have numerator and denominator. By positioning ourselves as students, we discuss the ideal design to help students in constructing the meaning of fractions.

  9. Fractional Dynamical Systems

    CERN Document Server

    Edelman, Mark

    2014-01-01

    In this paper the author presents the results of the preliminary investigation of fractional dynamical systems based on the results of numerical simulations of fractional maps. Fractional maps are equivalent to fractional differential equations describing systems experiencing periodic kicks. Their properties depend on the value of two parameters: the non-linearity parameter, which arises from the corresponding regular dynamical systems; and the memory parameter which is the order of the fractional derivative in the corresponding non-linear fractional differential equations. The examples of the fractional Standard and Logistic maps demonstrate that phase space of non-linear fractional dynamical systems may contain periodic sinks, attracting slow diverging trajectories, attracting accelerator mode trajectories, chaotic attractors, and cascade of bifurcations type trajectories whose properties are different from properties of attractors in regular dynamical systems. The author argues that discovered properties s...

  10. Solution to the Linear Fractional Differential Equation Using Adomian Decomposition Method

    Directory of Open Access Journals (Sweden)

    Jin-Fa Cheng

    2011-01-01

    Full Text Available We obtain the analytical general solution of the linear fractional differential equations with constant coefficients by Adomian decomposition method under nonhomogeneous initial value condition, which is in the sense of the Caputo fractional derivative.

  11. Digital Humanities and networked digital media

    OpenAIRE

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no ...

  12. On continued fraction algorithms

    NARCIS (Netherlands)

    Smeets, Ionica

    2010-01-01

    Is there a good continued fraction approximation between every two bad ones? What is the entropy of the natural extension for alpha-Rosen fractions? How do you find multi-dimensional continued fractions with a guaranteed quality in polynomial time? These, and many more, questions are answered in thi

  13. DIY Fraction Pack.

    Science.gov (United States)

    Graham, Alan; Graham, Louise

    2003-01-01

    Describes a very successful attempt to teach fractions to year 5 pupils based on pupils making their own fraction pack. Children decided for themselves how to make the fractional slices used in the activity using colored cardboard sheets and templates of a paper circle consisting of 24 equal slices. (Author/NB)

  14. On continued fraction algorithms

    NARCIS (Netherlands)

    Smeets, Ionica

    2010-01-01

    Is there a good continued fraction approximation between every two bad ones? What is the entropy of the natural extension for alpha-Rosen fractions? How do you find multi-dimensional continued fractions with a guaranteed quality in polynomial time? These, and many more, questions are answered in thi

  15. Decay Constants of Vector Mesons

    Institute of Scientific and Technical Information of China (English)

    LI Heng-Mei; WAN Shao-Long

    2008-01-01

    @@ The light vector mesons are studied within the framework of the Bethe-Salpeter equation with the vector-vectortype flat-bottom potential The Bethe-Salpeter wavefunctions and the decay constants of the vector mesons are obtained. All the obtained results, fρ, fφ, and fΚ* , are in agreement with the experimental values, respectively.

  16. Digital watermark

    Directory of Open Access Journals (Sweden)

    Jasna Maver

    2000-01-01

    Full Text Available The huge amount of multimedia contents available on the World-Wide-Web is beginning to raise the question of their protection. Digital watermarking is a technique which can serve various purposes, including intellectual property protection, authentication and integrity verification, as well as visible or invisible content labelling of multimedia content. Due to the diversity of digital watermarking applicability, there are many different techniques, which can be categorised according to different criteria. A digital watermark can be categorised as visible or invisible and as robust or fragile. In contrast to the visible watermark where a visible pattern or image is embedded into the original image, the invisible watermark does not change the visual appearance of the image. The existence of such a watermark can be determined only through a watermark ex¬traction or detection algorithm. The robust watermark is used for copyright protection, while the fragile watermark is designed for authentication and integrity verification of multimedia content. A watermark must be detectable or extractable to be useful. In some watermarking schemes, a watermark can be extracted in its exact form, in other cases, we can detect only whether a specific given watermarking signal is present in an image. Digital libraries, through which cultural institutions will make multimedia contents available, should support a wide range of service models for intellectual property protection, where digital watermarking may play an important role.

  17. The 1% concordance Hubble constant

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, C. L.; Larson, D.; Weiland, J. L. [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Hinshaw, G., E-mail: cbennett@jhu.edu [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z1 (Canada)

    2014-10-20

    The determination of the Hubble constant has been a central goal in observational astrophysics for nearly a hundred years. Extraordinary progress has occurred in recent years on two fronts: the cosmic distance ladder measurements at low redshift and cosmic microwave background (CMB) measurements at high redshift. The CMB is used to predict the current expansion rate through a best-fit cosmological model. Complementary progress has been made with baryon acoustic oscillation (BAO) measurements at relatively low redshifts. While BAO data do not independently determine a Hubble constant, they are important for constraints on possible solutions and checks on cosmic consistency. A precise determination of the Hubble constant is of great value, but it is more important to compare the high and low redshift measurements to test our cosmological model. Significant tension would suggest either uncertainties not accounted for in the experimental estimates or the discovery of new physics beyond the standard model of cosmology. In this paper we examine in detail the tension between the CMB, BAO, and cosmic distance ladder data sets. We find that these measurements are consistent within reasonable statistical expectations and we combine them to determine a best-fit Hubble constant of 69.6 ± 0.7 km s{sup –1} Mpc{sup –1}. This value is based upon WMAP9+SPT+ACT+6dFGS+BOSS/DR11+H {sub 0}/Riess; we explore alternate data combinations in the text. The combined data constrain the Hubble constant to 1%, with no compelling evidence for new physics.

  18. Variation of fundamental constants: theory

    Science.gov (United States)

    Flambaum, Victor

    2008-05-01

    Theories unifying gravity with other interactions suggest temporal and spatial variation of the fundamental ``constants'' in expanding Universe. There are some hints for the variation of different fundamental constants in quasar absorption spectra and Big Bang nucleosynthesis data. A large number of publications (including atomic clocks) report limits on the variations. We want to study the variation of the main dimensionless parameters of the Standard Model: 1. Fine structure constant alpha (combination of speed of light, electron charge and Plank constant). 2. Ratio of the strong interaction scale (LambdaQCD) to a fundamental mass like electron mass or quark mass which are proportional to Higgs vacuum expectation value. The proton mass is propotional to LambdaQCD, therefore, the proton-to-electron mass ratio comes into this second category. We performed necessary atomic, nuclear and QCD calculations needed to study variation of the fundamental constants using the Big Bang Nucleosynthsis, quasar spectra, Oklo natural nuclear reactor and atomic clock data. The relative effects of the variation may be enhanced in transitions between narrow close levels in atoms, molecules and nuclei. If one will study an enhanced effect, the relative value of systematic effects (which are not enhanced) may be much smaller. Note also that the absolute magnitude of the variation effects in nuclei (e.g. in very narrow 7 eV transition in 229Th) may be 5 orders of magnitude larger than in atoms. A different possibility of enhancement comes from the inversion transitions in molecules where splitting between the levels is due to the quantum tunneling amplitude which has strong, exponential dependence on the electron to proton mass ratio. Our study of NH3 quasar spectra has already given the best limit on the variation of electron to proton mass ratio.

  19. Varying Fine-Structure Constant and the Cosmological Constant Problem

    CERN Document Server

    Fujii, Y

    2003-01-01

    We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time-variability of the fine- structure constant $\\alpha$. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non- Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.

  20. Varying Fine-Structure Constant and the Cosmological Constant Problem

    Science.gov (United States)

    Fujii, Yasunori

    We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time variability of the fine-structure constant α. Comparing this with the recent result from the measurement of distant QSO's appears to indicate a non-uniform time-dependence, which we argue to be related to another recent finding of the accelerating universe. This view is implemented in terms of the scalar-tensor theory, applied specifically to the small but nonzero cosmological constant. Our detailed calculation shows that these two phenomena can be understood in terms of a common origin, a particular behavior of the scalar field, dilaton. We also sketch how this theoretical approach makes it appropriate to revisit non-Newtonian gravity featuring small violation of Weak Equivalence Principle at medium distances.

  1. New Quasar Studies Keep Fundamental Physical Constant Constant

    Science.gov (United States)

    2004-03-01

    Very Large Telescope sets stringent limit on possible variation of the fine-structure constant over cosmological time Summary Detecting or constraining the possible time variations of fundamental physical constants is an important step toward a complete understanding of basic physics and hence the world in which we live. A step in which astrophysics proves most useful. Previous astronomical measurements of the fine structure constant - the dimensionless number that determines the strength of interactions between charged particles and electromagnetic fields - suggested that this particular constant is increasing very slightly with time. If confirmed, this would have very profound implications for our understanding of fundamental physics. New studies, conducted using the UVES spectrograph on Kueyen, one of the 8.2-m telescopes of ESO's Very Large Telescope array at Paranal (Chile), secured new data with unprecedented quality. These data, combined with a very careful analysis, have provided the strongest astronomical constraints to date on the possible variation of the fine structure constant. They show that, contrary to previous claims, no evidence exist for assuming a time variation of this fundamental constant. PR Photo 07/04: Relative Changes with Redshift of the Fine Structure Constant (VLT/UVES) A fine constant To explain the Universe and to represent it mathematically, scientists rely on so-called fundamental constants or fixed numbers. The fundamental laws of physics, as we presently understand them, depend on about 25 such constants. Well-known examples are the gravitational constant, which defines the strength of the force acting between two bodies, such as the Earth and the Moon, and the speed of light. One of these constants is the so-called "fine structure constant", alpha = 1/137.03599958, a combination of electrical charge of the electron, the Planck constant and the speed of light. The fine structure constant describes how electromagnetic forces hold

  2. Fractional Differential Equations

    Directory of Open Access Journals (Sweden)

    Jianping Zhao

    2012-01-01

    Full Text Available An extended fractional subequation method is proposed for solving fractional differential equations by introducing a new general ansätz and Bäcklund transformation of the fractional Riccati equation with known solutions. Being concise and straightforward, this method is applied to the space-time fractional coupled Burgers’ equations and coupled MKdV equations. As a result, many exact solutions are obtained. It is shown that the considered method provides a very effective, convenient, and powerful mathematical tool for solving fractional differential equations.

  3. Fractional smith chart theory

    KAUST Repository

    Shamim, Atif

    2011-03-01

    For the first time, a generalized Smith chart is introduced here to represent fractional order circuit elements. It is shown that the standard Smith chart is a special case of the generalized fractional order Smith chart. With illustrations drawn for both the conventional integer based lumped elements and the fractional elements, a graphical technique supported by the analytical method is presented to plot impedances on the fractional Smith chart. The concept is then applied towards impedance matching networks, where the fractional approach proves to be much more versatile and results in a single element matching network for a complex load as compared to the two elements in the conventional approach. © 2010 IEEE.

  4. Constant-bandwidth constant-temperature hot-wire anemometer.

    Science.gov (United States)

    Ligeza, P

    2007-07-01

    A constant-temperature anemometer (CTA) enables the measurement of fast-changing velocity fluctuations. In the classical solution of CTA, the transmission band is a function of flow velocity. This is a minor drawback when the mean flow velocity does not significantly change, though it might lead to dynamic errors when flow velocity varies over a considerable range. A modification is outlined, whereby an adaptive controller is incorporated in the CTA system such that the anemometer's transmission band remains constant in the function of flow velocity. For that purpose, a second feedback loop is provided, and the output signal from the anemometer will regulate the controller's parameters such that the transmission bandwidth remains constant. The mathematical model of a CTA that has been developed and model testing data allow a through evaluation of the proposed solution. A modified anemometer can be used in measurements of high-frequency variable flows in a wide range of velocities. The proposed modification allows the minimization of dynamic measurement errors.

  5. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  6. Fractional statistical potential in graphene

    Science.gov (United States)

    Ardenghi, J. S.

    2017-03-01

    In this work the fractional statistics is applied to an anyon gas in graphene to obtain the special features that the arbitrary phase interchange of the particle coordinates introduce in the thermodynamic properties. The electron gas is constituted by N anyons in the long wavelength approximation obeying fractional exclusion statistics and the partition function is analyzed in terms of a perturbation expansion up to first order in the dimensionless constant λ / L being L the length of the graphene sheet and λ = βℏvF the thermal wavelength. By considering the correct permutation expansion of the many-anyons wavefunction, taking into account that the phase changes with the number of inversions in each permutation, the statistical fermionic/bosonic potential is obtained and the intermediate statistical behavior is found. It is shown that "extra" fermonic and bosonic particles states appears and this "statistical particle" distribution depends on N. Entropy and specific heat is obtained up to first order in λ / L showing that the results obtained differs from those obtained in different approximation to the fractional exclusion statistics.

  7. Digital Relationships

    DEFF Research Database (Denmark)

    Ledborg Hansen, Richard

    -­‐Jones, 2011) for increases in effectiveness and efficiency we indiscriminately embrace digital communication and digitized information dissemination with enthusiasm – at the risk of ignoring the potentially dark side of technology. However, technology also holds a promise for better understanding precisely...... of residual deposits from technology in organizations and its effect on individuals ability to connect to one another. Based on the case study the paper describes indications and suggests potential implication hereof. Given the inherent enhancement possibilities of technology our expectation for entertainment......-­rich information and highly interesting communication are sky-­high and rising. With a continuous increase in digitized communication follows a decrease in face-­to-­face encounters and our ability to engage in inter-­personal relationships are suffering for it (Davis, 2013). The behavior described in this paper...

  8. Digital Creativity

    DEFF Research Database (Denmark)

    Petersson Brooks, Eva; Brooks, Anthony Lewis

    2014-01-01

    This paper reports on a study exploring the outcomes from children’s play with technology in early childhood learning practices. The paper addresses questions related to how digital technology can foster creativity in early childhood learning environments. It consists of an analysis of children......’s interaction with the KidSmart furniture focusing on digital creativity potentials and play values suggested by the technology. The study applied a qualitative approach and included125 children (aged three to five), 10 pedagogues, and two librarians. The results suggests that educators should sensitively...... consider intervening when children are interacting with technology, and rather put emphasize into the integration of the technology into the environment and to the curriculum in order to shape playful structures for children’s digital creativity....

  9. Fractional Dynamics and Control

    CERN Document Server

    Machado, José; Luo, Albert

    2012-01-01

    Fractional Dynamics and Control provides a comprehensive overview of recent advances in the areas of nonlinear dynamics, vibration and control with analytical, numerical, and experimental results. This book provides an overview of recent discoveries in fractional control, delves into fractional variational principles and differential equations, and applies advanced techniques in fractional calculus to solving complicated mathematical and physical problems.Finally, this book also discusses the role that fractional order modeling can play in complex systems for engineering and science. Discusses how fractional dynamics and control can be used to solve nonlinear science and complexity issues Shows how fractional differential equations and models can be used to solve turbulence and wave equations in mechanics and gravity theories and Schrodinger’s equation  Presents factional relaxation modeling of dielectric materials and wave equations for dielectrics  Develops new methods for control and synchronization of...

  10. Fractional factorial plans

    CERN Document Server

    Dey, Aloke

    2009-01-01

    A one-stop reference to fractional factorials and related orthogonal arrays.Presenting one of the most dynamic areas of statistical research, this book offers a systematic, rigorous, and up-to-date treatment of fractional factorial designs and related combinatorial mathematics. Leading statisticians Aloke Dey and Rahul Mukerjee consolidate vast amounts of material from the professional literature--expertly weaving fractional replication, orthogonal arrays, and optimality aspects. They develop the basic theory of fractional factorials using the calculus of factorial arrangements, thereby providing a unified approach to the study of fractional factorial plans. An indispensable guide for statisticians in research and industry as well as for graduate students, Fractional Factorial Plans features: * Construction procedures of symmetric and asymmetric orthogonal arrays. * Many up-to-date research results on nonexistence. * A chapter on optimal fractional factorials not based on orthogonal arrays. * Trend-free plans...

  11. Fotografia digital

    OpenAIRE

    Vinicius Cauduro, Flávio; Pontifícia Universidade Católica do Rio Grande do Sul

    2008-01-01

    Poderíamos talvez definir como sendo fotografia digital toda e qualquer imagem obtida a partir de uma camera obscura, com características ótico-mecânicas variáveis através de princípios puramente analógicos ou por combinação híbrida (analógico/digital), e que seja posteriormente processada em computador e exibida de forma projetada (monitor ou tela) ou imprensa (papel ou filme).

  12. Digital photogrammetry

    CERN Document Server

    Egels, Yves

    2003-01-01

    Photogrammetry is the use of photography for surveying primarily and is used for the production of maps from aerial photographs. Along with remote sensing, it represents the primary means of generating data for Geographic Information Systems (GIS). As technology develops, it is becoming easier to gain access to it. The cost of digital photogrammetric workstations are falling quickly and these new tools are therefore becoming accessible to more and more users. Digital Photogrammetry is particularly useful as a text for graduate students in geomantic and is also suitable for people with a good basic scientific knowledge who need to understand photogrammetry, and who wish to use the book as a reference.

  13. Digital literacies

    CERN Document Server

    Hockly, Nicky; Pegrum, Mark

    2014-01-01

    Dramatic shifts in our communication landscape have made it crucial for language teaching to go beyond print literacy and encompass the digital literacies which are increasingly central to learners' personal, social, educational and professional lives. By situating these digital literacies within a clear theoretical framework, this book provides educators and students alike with not just the background for a deeper understanding of these key 21st-century skills, but also the rationale for integrating these skills into classroom practice. This is the first methodology book to address not jus

  14. Digital communication

    CERN Document Server

    Das, Apurba

    2010-01-01

    ""Digital Communications"" presents the theory and application of the philosophy of Digital Communication systems in a unique but lucid form. This book inserts equal importance to the theory and application aspect of the subject whereby the authors selected a wide class of problems. The Salient features of the book are: the foundation of Fourier series, Transform and wavelets are introduces in a unique way but in lucid language; the application area is rich and resemblance to the present trend of research, as we are attached with those areas professionally; a CD is included which contains code

  15. Digital filters

    CERN Document Server

    Hamming, Richard W

    1997-01-01

    Digital signals occur in an increasing number of applications: in telephone communications; in radio, television, and stereo sound systems; and in spacecraft transmissions, to name just a few. This introductory text examines digital filtering, the processes of smoothing, predicting, differentiating, integrating, and separating signals, as well as the removal of noise from a signal. The processes bear particular relevance to computer applications, one of the focuses of this book.Readers will find Hamming's analysis accessible and engaging, in recognition of the fact that many people with the s

  16. Evolving digital ecological networks.

    Science.gov (United States)

    Fortuna, Miguel A; Zaman, Luis; Wagner, Aaron P; Ofria, Charles

    2013-01-01

    "It is hard to realize that the living world as we know it is just one among many possibilities" [1]. Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs (i.e., digital organisms) that experience the same major ecological interactions as biological organisms (e.g., competition, predation, parasitism, and mutualism). Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations (hereafter tasks) that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology (e.g., the extent to which the architecture of multispecies networks shape coevolutionary outcomes, and the processes involved).

  17. Evolving digital ecological networks.

    Directory of Open Access Journals (Sweden)

    Miguel A Fortuna

    Full Text Available "It is hard to realize that the living world as we know it is just one among many possibilities" [1]. Evolving digital ecological networks are webs of interacting, self-replicating, and evolving computer programs (i.e., digital organisms that experience the same major ecological interactions as biological organisms (e.g., competition, predation, parasitism, and mutualism. Despite being computational, these programs evolve quickly in an open-ended way, and starting from only one or two ancestral organisms, the formation of ecological networks can be observed in real-time by tracking interactions between the constantly evolving organism phenotypes. These phenotypes may be defined by combinations of logical computations (hereafter tasks that digital organisms perform and by expressed behaviors that have evolved. The types and outcomes of interactions between phenotypes are determined by task overlap for logic-defined phenotypes and by responses to encounters in the case of behavioral phenotypes. Biologists use these evolving networks to study active and fundamental topics within evolutionary ecology (e.g., the extent to which the architecture of multispecies networks shape coevolutionary outcomes, and the processes involved.

  18. Robust Image Watermarking using Fractional Sinc Transformation

    Directory of Open Access Journals (Sweden)

    Almas Abbasi

    2016-09-01

    Full Text Available The increased utilization of internet in sharing and dissemination of digital data makes it is very difficult to maintain copyright and ownership of data. Digital watermarking offers a method for authentication and copyright protection. Digital image watermarking is an important technique for the multimedia content authentication and copyright protection. This paper present a watermarking algorithm making a balance between imperceptibility and robustness based on fractional calculus and also a domain has constructed using fractional Sinc function (FSc. The FSc model the signal as polynomial for watermark embedding. Watermark is embedded in all the coefficients of the image. Cross correlation method based on Neyman-Pearson is used for watermark detection. Moreover fraction rotation expression has constructed to achieve rotation. Experimental results confirmed the proposed technique has good robustness and outperformed another technique in imperceptibility. Furthermore the proposed method enables blind watermark detection where the original image is not required during the watermark detection and thus making it more practical than non-blind watermarking techniques.

  19. Dependence of stability of metastable superconductors on copper fraction

    Energy Technology Data Exchange (ETDEWEB)

    Elrod, S. A.; Lue, J. W.; Miller, J. R.; Dresner, L.

    1980-12-01

    The stability of composite superconductors operating in the metastable regime depends upon such factors as matrix resistivity, cooled surface dimensions, fraction of critical current, and volume fraction of stabilizer. By assuming constant thermophysical properties, we developed analytic expressions for the energy and voltage of the minimum propagating zone (MPZ). With other factors held constant, these expressions have been used to predict composite superconductor stability as a function of copper fraction: lower copper fractions lead to higher MPZ energies. MPZ voltages have been measured for three NbTi/Cu composites having different copper fractions and different critical current densities for several magnetic fields and transport currents. Experimental MPZ voltages have been used to calculate an effective heat transfer coefficient, which is subsequently used to calculate the MPZ energy. The experimental MPZ energies support the theoretical expectation that lower copper fractions lead to higher stability in the metastable regime.

  20. Variation in Children's Understanding of Fractions: Preliminary Findings

    Science.gov (United States)

    Fonger, Nicole L.; Tran, Dung; Elliott, Natasha

    2015-01-01

    This research targets children's informal strategies and knowledge of fractions by examining their ability to create, interpret, and connect representations in doing and communicating mathematics when solving fractions tasks. Our research group followed a constant comparative method to analyze clinical interviews of children in grades 2-6 solving…

  1. Bio-oil fractionation and condensation

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Robert C.; Jones, Samuel T.; Pollard, Anthony

    2017-04-04

    The present invention relates to a method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also disclosed are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

  2. Bio-oil fractionation and condensation

    Science.gov (United States)

    Brown, Robert C; Jones, Samuel T; Pollard, Anthony

    2013-07-02

    A method of fractionating bio-oil vapors which involves providing bio-oil vapors comprising bio-oil constituents is described. The bio-oil vapors are cooled in a first stage which comprises a condenser having passages for the bio-oil separated by a heat conducting wall from passages for a coolant. The coolant in the condenser of the first stage is maintained at a substantially constant temperature, set at a temperature in the range of 75 to 100.degree. C., to condense a first liquid fraction of liquefied bio-oil constituents in the condenser of the first stage. The first liquid fraction of liquified bio-oil constituents from the condenser in the first stage is collected. Also described are steps for subsequently recovering further liquid fractions of liquefied bio-oil constituents. Particular compositions of bio-oil condensation products are also described.

  3. Three pion nucleon coupling constants

    CERN Document Server

    Arriola, E Ruiz; Perez, R Navarro

    2016-01-01

    There exist four pion nucleon coupling constants, $f_{\\pi^0, pp}$, $-f_{\\pi^0, nn}$, $f_{\\pi^+, pn} /\\sqrt{2}$ and $ f_{\\pi^-, np} /\\sqrt{2}$ which coincide when up and down quark masses are identical and the electron charge is zero. While there is no reason why the pion-nucleon-nucleon coupling constants should be identical in the real world, one expects that the small differences might be pinned down from a sufficiently large number of independent and mutually consistent data. Our discussion provides a rationale for our recent determination $$f_p^2 = 0.0759(4) \\, , \\quad f_{0}^2 = 0.079(1) \\,, \\quad f_{c}^2 = 0.0763(6) \\, , $$ based on a partial wave analysis of the $3\\sigma$ self-consistent nucleon-nucleon Granada-2013 database comprising 6713 published data in the period 1950-2013.

  4. Time-Varying Fundamental Constants

    Science.gov (United States)

    Olive, Keith

    2003-04-01

    Recent data from quasar absorption systems can be interpreted as arising from a time variation in the fine-structure constant. However, there are numerous cosmological, astro-physical, and terrestrial bounds on any such variation. These includes bounds from Big Bang Nucleosynthesis (from the ^4He abundance), the Oklo reactor (from the resonant neutron capture cross-section of Sm), and from meteoretic lifetimes of heavy radioactive isotopes. The bounds on the variation of the fine-structure constant are significantly strengthened in models where all gauge and Yukawa couplings vary in a dependent manner, as would be expected in unified theories. Models which are consistent with all data are severly challenged when Equivalence Principle constraints are imposed.

  5. Type 1 Active Galactic Nucleus Fraction in SDSS/FIRST Survey

    CERN Document Server

    Lu, Yu; Dong, Xiao-Bo; Zhou, Hong-Yan

    2010-01-01

    In the unification scheme, narrow-lined (type 2) active galactic nuclei (AGN) are intrinsically similar to broad-lined (type 1) AGN with the exception that the line of sight to the broad emission line region and accretion disk is blocked by a dusty torus. The fraction of type 1 AGN measures the average covering factor of the torus. In this paper, we explore the dependence of this fraction on nuclear properties for a sample of low redshift (z 10^{23}W/Hz) AGN selected by matching the spectroscopic catalog of Sloan Digital Sky Survey and the radio source catalog of Faint Image of Radio Sky at Twenty cm. After correcting for several selection effects, we find that : (1) type 1 fraction $f_1$ keeps at a constant of ~20 per cent in the [O III] 5007 luminosity range of 40.7< log(L_{[O III]}/ erg/s) <43.5 . This result is significantly different from previous studies, and the difference can be explained by extinction correction and different treatment of selection effects. (2) $f_1$ rises with black hole mass ...

  6. A direct measurement of the baryonic mass function of galaxies & implications for the galactic baryon fraction

    CERN Document Server

    Papastergis, Emmanouil; Huang, Shan; Giovanelli, Riccardo; Haynes, Martha P

    2012-01-01

    We use both an HI-selected and an optically-selected galaxy sample to directly measure the abundance of galaxies as a function of their "baryonic" mass (stars + atomic gas). Stellar masses are calculated based on optical data from the Sloan Digital Sky Survey (SDSS) and atomic gas masses are calculated using atomic hydrogen (HI) emission line data from the Arecibo Legacy Fast ALFA (ALFALFA) survey. By using the technique of abundance matching, we combine the measured baryonic function (BMF) of galaxies with the dark matter halo mass function in a LCDM universe, in order to determine the galactic baryon fraction as a function of host halo mass. We find that the baryon fraction of low-mass halos is much smaller than the cosmic value, even when atomic gas is taken into account. We find that the galactic baryon deficit increases monotonically with decreasing halo mass, in contrast with previous studies which suggested an approximately constant baryon fraction at the low-mass end. We argue that the observed baryon...

  7. Dividing Fractions: A Pedagogical Technique

    Science.gov (United States)

    Lewis, Robert

    2016-01-01

    When dividing one fraction by a second fraction, invert, that is, flip the second fraction, then multiply it by the first fraction. To multiply fractions, simply multiply across the denominators, and multiply across the numerators to get the resultant fraction. So by inverting the division of fractions it is turned into an easy multiplication of…

  8. Digitalization Boosting Novel Digital Services for Consumers

    Directory of Open Access Journals (Sweden)

    Kaisa Vehmas

    Full Text Available Digitalization has changed the world. The digital revolution has promoted the Internet, and more recently mobile network infrastructure, as the technological backbone of our society. Digital technologies have become more integrated across all sectors of o ...

  9. Spectrophotometric determination of acidity constants of some anthraquinones and anthrones in methanol-water mixtures.

    Science.gov (United States)

    Shamsipur, M; Ghasemi, J; Tamaddon, F; Sharghi, H

    1993-05-01

    The acidity constants of some synthetic derivatives of 9,10-anthraquinone and 9-anthrone in methanol-water mixtures at 25 degrees have been determined spectrophotometrically. A linear reverse relationship is observed between pK(a1) of all acids and the mole fraction of methanol. The influence of substituents in the molecular structure on the ionization constants is discussed.

  10. Digital Methods

    NARCIS (Netherlands)

    Rogers, R.

    2013-01-01

    In Digital Methods, Richard Rogers proposes a methodological outlook for social and cultural scholarly research on the Web that seeks to move Internet research beyond the study of online culture. It is not a toolkit for Internet research, or operating instructions for a software package; it deals wi

  11. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  12. Digital Tidbits

    Science.gov (United States)

    Kumaran, Maha; Geary, Joe

    2011-01-01

    Technology has transformed libraries. There are digital libraries, electronic collections, online databases and catalogs, ebooks, downloadable books, and much more. With free technology such as social websites, newspaper collections, downloadable online calendars, clocks and sticky notes, online scheduling, online document sharing, and online…

  13. Digital radiography

    DEFF Research Database (Denmark)

    Precht, H; Gerke, O; Rosendahl, K

    2012-01-01

    BACKGROUND: New developments in processing of digital radiographs (DR), including multi-frequency processing (MFP), allow optimization of image quality and radiation dose. This is particularly promising in children as they are believed to be more sensitive to ionizing radiation than adults...

  14. Digital books.

    Science.gov (United States)

    Wink, Diane M

    2011-01-01

    In this bimonthly series, the author examines how nurse educators can use the Internet and Web-based computer technologies such as search, communication, and collaborative writing tools; social networking and social bookmarking sites; virtual worlds; and Web-based teaching and learning programs. This article describes digital books.

  15. Digital forvaltning

    DEFF Research Database (Denmark)

    Remmen, Arne; Larsen, Torben; Mosgaard, Mette

    2004-01-01

    Større effektivitet, bedre service og mere demokrai er blot nogle af forventningerne til indførelse af digital forveltning i kommunerne. Kapitlet giver bland andet svar på spørgsmålene : Hvordan lever kommunerne op hertil i dagligdagen? hvilke virkemidler anvender de? Hvilke barrierer har der været...

  16. Digital Batteries

    Science.gov (United States)

    Hubler, Alfred

    2009-03-01

    The energy density in conventional capacitors is limited by sparking. We present nano-capacitor arrays, where - like in laser diodes and quantum wells [1] - quantization prevents dielectric breakthrough. We show that the energy density and the power/weight ratio are very high, possibly larger than in hydrogen [2]. Digital batteries are a potential clean energy source for cars, laptops, and mobile devices. The technology is related to flash drives. However, because of the high energy density, safety is a concern. Digital batteries can be easily and safely charged and discharged. In the discharged state they pose no danger. Even if a charged digital battery were to explode, it would produce no radioactive waste, no long-term radiation, and probably could be designed to produce no noxious chemicals. We discuss methodologies to prevent shorts and other measures to make digital batteries safe. [1] H. Higuraskh, A. Toriumi, F. Yamaguchi, K. Kawamura, A. Hubler, Correlation Tunnel Device, U. S. Patent No. 5,679,961 (1997) [2] Alfred Hubler, http://server10.how-why.com/blog/

  17. Fokus: Digital

    DEFF Research Database (Denmark)

    2014-01-01

    sammenhænge og fra forandrede distributionsformer. Dette betyder ændrede betingelser for både produktion og reception af kunstmusik og lydkunst. Med Digital tager vi udgangspunkt i fire komponisters meget forskellige bud på hvordan teknologien spiller en rolle i arbejdet. Juliana Hodkinson beskriver hvordan...

  18. A Single-Chip 8-Band CMOS Transceiver for 3G Cellular Systems with Digital Interface

    Science.gov (United States)

    Yoshida, Hiroshi; Toyoda, Takehiko; Tsurumi, Hiroshi; Itoh, Nobuyuki

    In this paper, a single-chip dual-mode 8-band 130nm CMOS transceiver including A/D/A converters and digital filters with 312MHz LVDS interface is presented. For a transmitter chain, linear direct quadrature modulation architecture is introduced for both W-CDMA/HSDPA (High Speed Uplink Packet Access) and for GSM/EDGE. Analog baseband LPFs and quadrature modulators are commonly used both for GSM and for EDGE. For a direct conversion receiver chain, ABB (Analog Base-Band) blocks, i.e., LPFs and VGAs, delta-sigma A/D converters, and FIR filters are commonly used for W-CDMA/HSDPA (High Speed Downlink Packet Access) and GSM/EDGE to reduce chip area. Their characteristics can be reconfigured by register-based control sequence. The receiver chain also includes high-speed DC offset cancellers both in analog and in digital stage, and the self-contained AGC controller, whose parameters such as time constant are programmable to be free from DBB (Digital Base-Band) control. The transceiver also includes wide-range VCOs and fractional PLLs, an LVDS driver and receiver for high-speed digital interface of 312MHz. Measured results reveal that the transceiver satisfies 3GPP specifications for W-CDMA/HSPA (High Speed Packet Access) and GSM/EDGE.

  19. Study of time resolution by digital methods with DRS4 system

    CERN Document Server

    Du, Cheng-Ming; Zhang, Xiu-Ling; Yang, Hai-Bo; Cheng, Ke; Hu, Zheng-Guo; Sun, Zhi-Yu; Xu, Hu-Shan

    2015-01-01

    A new Digital Pulse Processing (DPP) system, based on domino ring sampler version 4 (DRS4), with good time resolution for the LaBr3 detectors has been developed and different digital timing analysis methods for processing the detector raw signals are reported. The system, composed of an eight channels DRS4 chip, was used as the readout electronic and acquisition system to process the outputs signals from XP20D0 Photomultiplier Tubes (PMTs). The PMTs were coupled with LaBr3 scintillator and placed on opposite side of the radioactive positron 22Na source for 511keV gama-ray test. By analyzing the raw data acquired by the system, the best coincidence timing resolution is about 194.7ps (FWHM), obtained by the digital constant fraction discrimination (dCFD) method and better than the other digital methods and analysis method based on the conventional analog systems. The results indicate that it is a promising approach to better localize the positron annihilation in the positron emission tomography (PET) with time ...

  20. Digital pulse-timing technique for the neutron detector array NEDA

    Energy Technology Data Exchange (ETDEWEB)

    Modamio, V., E-mail: victor.modamio@lnl.infn.it [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Valiente-Dobón, J.J. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Jaworski, G. [Faculty of Physics, Warsaw University of Technology, 00-662 Warszawa (Poland); Heavy Ion Laboratory, University of Warsaw, 02-093 Warszawa (Poland); Hüyük, T. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Triossi, A. [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); Egea, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Department of Electronic Engineering, Universitat de València, E-46100 Burjassot (Spain); Di Nitto, A. [Johannes Gutenberg-Universität Mainz, D-55099 Mainz (Germany); Söderström, P.-A. [RIKEN Nishina Center, 2-1 Hirosawa, Wako-shi, 351-0198 Saitama (Japan); Agramunt Ros, J. [Instituto de Física Corpuscular, CSIC-Universitat de València, E-46980 Valencia (Spain); Angelis, G. de [Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy); France, G. de [GANIL, CEA/DSAM and CNRS/IN2P3, F-14076 Caen (France); Erduran, M.N. [Faculty of Engineering and Natural Sciences, Istanbul Sabahattin Zaim University, 34303 Istanbul (Turkey); and others

    2015-03-01

    A new digital pulse-timing algorithm, to be used with the future neutron detector array NEDA, has been developed and tested. The time resolution of four 5 in. diameter photomultiplier tubes (XP4512, R4144, R11833-100, and ET9390-kb), coupled to a cylindrical 5 in. by 5 in. BC501A liquid scintillator detector was measured by employing digital sampling electronics and a constant fraction discriminator (CFD) algorithm. The zero crossing of the CFD algorithm was obtained with a cubic spline interpolation, which was continuous up to the second derivative. The performance of the algorithm was studied at sampling rates of 500 MS/s and 200 MS/s. The time resolution obtained with the digital electronics was compared to the values acquired with a standard analog CFD. The result of this comparison shows that the time resolution from the analog and the digital measurements at 500 MS/s and at 200 MS/s are within 15% for all the tested photomultiplier tubes.

  1. Why isn't the solar constant a constant?

    CERN Document Server

    Li, K J; Xu, J C; Gao, P X; Yang, L H; Liang, H F; Zhan, L S

    2012-01-01

    In order to probe the mechanism of variations of the Solar Constant on the inter-solar-cycle scale, total solar irradiance (TSI, the so-called Solar Constant) in the time interval of 7 November 1978 to 20 September 2010 is decomposed into three components through the empirical mode decomposition and time-frequency analyses. The first component is the rotation signal, counting up to 42.31% of the total variation of TSI, which is understood to be mainly caused by large magnetic structures, including sunspot groups. The second is an annual-variation signal, counting up to 15.17% of the total variation, the origin of which is not known at this point in time. Finally, the third is the inter-solar-cycle signal, counting up to 42.52%, which are inferred to be caused by the network magnetic elements in quiet regions, whose magnetic flux ranges from $(4.27-38.01)\\times10^{19}$ Mx.

  2. Fractional Pure Birth Processes

    CERN Document Server

    Orsingher, Enzo; 10.3150/09-BEJ235

    2010-01-01

    We consider a fractional version of the classical non-linear birth process of which the Yule-Furry model is a particular case. Fractionality is obtained by replacing the first-order time derivative in the difference-differential equations which govern the probability law of the process, with the Dzherbashyan-Caputo fractional derivative. We derive the probability distribution of the number $ \\mathcal{N}_\

  3. Fractional vortex Hilbert's Hotel

    CERN Document Server

    Gbur, Greg

    2015-01-01

    We demonstrate how the unusual mathematics of transfinite numbers, in particular a nearly perfect realization of Hilbert's famous hotel paradox, manifests in the propagation of light through fractional vortex plates. It is shown how a fractional vortex plate can be used, in principle, to create any number of "open rooms," i.e. topological charges, simultaneously. Fractional vortex plates are therefore demonstrated to create a singularity of topological charge, in which the vortex state is completely undefined and in fact arbitrary.

  4. Fractional Electromagnetic Waves

    CERN Document Server

    Gómez, J F; Bernal, J J; Tkach, V I; Guía, M

    2011-01-01

    In the present work we consider the electromagnetic wave equation in terms of the fractional derivative of the Caputo type. The order of the derivative being considered is 0 <\\gamma<1. A new parameter \\sigma, is introduced which characterizes the existence of the fractional components in the system. We analyze the fractional derivative with respect to time and space, for \\gamma = 1 and \\gamma = 1/2 cases.

  5. On the uniqueness of d-vertex magic constant

    Directory of Open Access Journals (Sweden)

    Arumugam S.

    2014-05-01

    Full Text Available Let G = (V,E be a graph of order n and let D ⊆ {0, 1, 2, 3, . . .}. For v ∈ V, let ND(v = {u ∈ V : d(u, v ∈ D}. The graph G is said to be D-vertex magic if there exists a bijection f : V (G → {1, 2, . . . , n} such that for all v ∈ V, ∑uv∈ND(v f(u is a constant, called D-vertex magic constant. O’Neal and Slater have proved the uniqueness of the D-vertex magic constant by showing that it can be determined by the D-neighborhood fractional domination number of the graph. In this paper we give a simple and elegant proof of this result. Using this result, we investigate the existence of distance magic labelings of complete r-partite graphs where r ≥ 4.

  6. TARGET DETECTION USING MULTI-RESOLUTION ANALYSIS AND HOLDER CONSTANT

    Institute of Scientific and Technical Information of China (English)

    Liu Wenyu; Li Hua; Zhu Guangxi

    2001-01-01

    Through analyzing the different height parameter of 3D surface between the artificial target and complex background based on the description of average Holder constant of fractional Brownian motion, a novel method of target detection based on wavelet transformation and Holder constant is proposed. The wavelet Holder constants are calculated and linearly interpolated in a series of images, the target is detected by testing the linearity errof The more accurate localization can be achieved using two images of the same region but with difIerent scaling parameters.The application results of this algorithm for target detection are also given, and show that this method has good performance of noise immunity. This method is also suitable for identifying specific targets in complex background.

  7. Digital Humanities and networked digital media

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    This article discusses digital humanities and the growing diversity of digital media, digital materials and digital methods. The first section describes the humanities computing tradition formed around the interpretation of computation as a rule-based process connected to a concept of digital...... of software-supported methods. This is so, in part, because of the complexity of the world and, in part, because digital media remain open to the projection of new epistemologies onto the functional architecture of these media. The third section discusses the heterogeneous character of digital materials...... materials centred on the digitisation of non-digital, finite works, corpora and oeuvres. The second section discusses “the big tent” of contemporary digital humanities. It is argued that there can be no unifying interpretation of digital humanities above the level of studying digital materials with the help...

  8. Cryptography in constant parallel time

    CERN Document Server

    Applebaum, Benny

    2013-01-01

    Locally computable (NC0) functions are 'simple' functions for which every bit of the output can be computed by reading a small number of bits of their input. The study of locally computable cryptography attempts to construct cryptographic functions that achieve this strong notion of simplicity and simultaneously provide a high level of security. Such constructions are highly parallelizable and they can be realized by Boolean circuits of constant depth.This book establishes, for the first time, the possibility of local implementations for many basic cryptographic primitives such as one-way func

  9. Henry's law constants of polyols

    Directory of Open Access Journals (Sweden)

    S. Compernolle

    2014-05-01

    Full Text Available Henry's law constants (HLC are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. Depending on the case, infinite dilution activity coefficients (IDACs, solid state pressures or activity coefficient ratios are obtained as intermediary results. For most compounds, these are the first values reported, while others compare favourably with literature data in most cases. Using these values and those from a previous work (Compernolle and Müller, 2014, an assessment is made on the partitioning of polyols, diacids and hydroxy acids to droplet and aqueous aerosol.

  10. Exact constants in approximation theory

    CERN Document Server

    Korneichuk, N

    1991-01-01

    This book is intended as a self-contained introduction for non-specialists, or as a reference work for experts, to the particular area of approximation theory that is concerned with exact constants. The results apply mainly to extremal problems in approximation theory, which in turn are closely related to numerical analysis and optimization. The book encompasses a wide range of questions and problems: best approximation by polynomials and splines; linear approximation methods, such as spline-approximation; optimal reconstruction of functions and linear functionals. Many of the results are base

  11. More than just halo mass: Modelling how the red galaxy fraction depends on multiscale density in a HOD framework

    CERN Document Server

    Phleps, Stefanie; Zibetti, Stefano; Budavári, Tamás

    2013-01-01

    The fraction of galaxies with red colours depends sensitively on environment, and on the way in which environment is measured. To distinguish competing theories for the quenching of star formation, a robust and complete description of environment is required, to be applied to a large sample of galaxies. The environment of galaxies can be described using the density field of neighbours on multiple scales - the multiscale density field. We are using the Millennium simulation and a simple HOD prescription which describes the multiscale density field of Sloan Digital Sky Survey DR7 galaxies to investigate the dependence of the fraction of red galaxies on the environment. Using a volume limited sample where we have sufficient galaxies in narrow density bins, we have more dynamic range in halo mass and density for satellite galaxies than for central galaxies. Therefore we model the red fraction of central galaxies as a constant while we use a functional form to describe the red fraction of satellites as a function ...

  12. Digital Plasmonics

    CERN Document Server

    Gjonaj, Bergin; Johnson, Patrick M; Mosk, Allard P; Kuipers, Kobus; Lagendijk, Ad

    2010-01-01

    The field of plasmonics offers a route to control light fields with metallic nanostructures through the excitation of Surface Plasmon Polaritons (SPPs). These surface waves, bound to a metal dielectric interface, tightly confine electromagnetic energy. Active control over SPPs has potential for applications in sensing, photovoltaics, quantum communication, nano circuitry, metamaterials and super-resolution microscopy. We achieve here a new level of control of plasmonic fields using a digital spatial light modulator. Optimizing the plasmonic phases via feedback we focus SPPs at a freely pre-chosen point on the surface of a nanohole array with high resolution. Digital addressing and scanning of SPPs without mechanical motion will enable novel interdisciplinary applications of advanced plasmonic devices in cell microscopy, optical data storage and sensing.

  13. Digital tachometer

    Science.gov (United States)

    Shirokov, B.

    1984-03-01

    A tachometer with digital indication was built for measuring the speed of automobile engines with only two digits in the rpm readout. It consists of a Schmitt trigger for shaping input pulses, a pulse counter, a cycle time setting multivibrator and a readout time setting multivibrator, a stabilizer, a flicker suppressor, and a capacitive transducer. The instrument operates from a 12 V battery and draws 180 mA. The transducer includes a 30 to 50 turns coil of PEL 0.5 wire wound around the conductor which connects the ignition coil to the engine distributor and its transistor is mounted on a fin-type heat sink. Tuneup of the tachometer involves matching the transducer capacitor for maximum voltage at minimum current and trimming the readout time setting multivibrator with its adjustable resistor for a 1.5 readout with a 50 Hz input signal.

  14. Digital resources

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2005-12-01

    Full Text Available Bibliotheca Latinitatis Mediaevalis (circa VII sec. - XIV sec. IntraText Digital Library [01/06] Corpus Scriptorum Latinorum. A digital library of Latin literature by David Camden [01/06] Fonti disponibili online concernenti la vita religiosa medievale Rete Vitae Religiosae Mediaevalis Studia Conectens [01/06] Fuentes del Medievo Hispanico Instituto de Historia, Consejo Superior de Investigaciones Científicas [01/06] Latin Literature Forum Romanum [01/06] Ludovico Antonio Muratori, Dissertazioni sopra le antichità italiane, 1751 Biblioteca dei Classici Italiani di Giuseppe Bonghi [01/06] Medieval Latin The Latin Library [01/06] Médiévales Presses Universitaires de Vincennes - Revues.org [01/06] Regesta imperii Deutsche Kommission für die Bearbeitung der Regesta Imperii e.V. [01/06] Suda On Line Byzantine Lexicography [01/06

  15. Kepler's Constant and WDS Orbit

    CERN Document Server

    Siregar, S

    2012-01-01

    The aim of this work are to find a Kepler's constant by using polynomial regression of the angular separation \\rho = \\rho(t) and the position angle \\theta = \\theta(t). The Kepler's constant obtained is used to derive the element of orbit. As a case study the angular separation and the position angle of the WDS 00063 +5826 and the WDS 04403-5857 were investigated. For calculating the element of orbit the Thiele-Innes van den Bos method is used. The rough data of the angular separation \\rho(t) and the position angle \\theta(t) are taken from the US Naval Observatory, Washington. This work also presents the masses and absolute bolometric magnitudes of each star.These stars include into the main-sequence stars with the spectral class G5V for WDS04403-5857and the type of spectrum G3V for WDS 00063+5826. The life time of the primary star and the secondary star of WDS 04403-5857 nearly equal to 20 Gyr. The life time of the primary star and the secondary star of WDS 00063+5826 are 20 Gyr and 19 Gyr, respectively.

  16. Becoming digital

    DEFF Research Database (Denmark)

    Pors, Anja Svejgaard

    2015-01-01

    . Originality/value: The study contributes to ethnographic research in public administration by combining two separate subfields, e-government and street-level bureaucracy, to discern recent transformations in public service delivery. In the digital era, tasks, control and equality are distributed in ways...... that call for symmetrical and relational approaches to studying street-level bureaucracy. The argument goes beyond technological or social determinism to find a fruitful intermediary position pointing at technological change as having both constraining and enabling effects....

  17. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  18. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    Artiklen præsenterer først nogle generelle problemstillinger omkring Digital Humanities (DH) med det formål at undersøge dem nærmere i relation til konkrete eksempler på forskellige digitaliseringsmåder og ændringer i dokumentproduktion. I en nærmere afgrænsning vælger artiklen den tendens i DH...

  19. Fractional and noncommutative spacetimes

    NARCIS (Netherlands)

    Arzano, M.; Calcagni, M.; Oriti, D.; Scalisi, M.

    2011-01-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determi

  20. Can Kindergartners Do Fractions?

    Science.gov (United States)

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems (Empson…

  1. Can Kindergartners Do Fractions?

    Science.gov (United States)

    Cwikla, Julie

    2014-01-01

    Mathematics professor Julie Cwikla decided that she needed to investigate young children's understandings and see what precurricular partitioning notions young minds bring to the fraction table. Cwikla realized that only a handful of studies have examined how preschool-age and early elementary school-age students solve fraction problems (Empson…

  2. An Appetite for Fractions

    Science.gov (United States)

    Wilkerson, Trena L.; Bryan, Tommy; Curry, Jane

    2012-01-01

    This article describes how using candy bars as models gives sixth-grade students a taste for learning to represent fractions whose denominators are factors of twelve. Using paper models of the candy bars, students explored and compared fractions. They noticed fewer different representations for one-third than for one-half. The authors conclude…

  3. Categories of Fractions Revisited

    OpenAIRE

    Fritz, Tobias

    2008-01-01

    The theory of categories of fractions as originally developed by Gabriel and Zisman is reviewed in a pedagogical manner giving detailed proofs of all statements. A weakening of the category of fractions axioms used by Higson is discussed and shown to be equivalent to the original axioms.

  4. On fractional programming

    Energy Technology Data Exchange (ETDEWEB)

    Bajona-Xandri, C.; Martinez-Legaz, J.E.

    1994-12-31

    This paper studies the minimax fractional programming problem, assuming quasiconvexity of the objective function, under the lower subdifferentiability viewpoint. Necessary and sufficient optimality conditions and dual properties are found. We present applications of this theory to find the Pareto efficient solutions of a multiobjective fractional problem and to solve several economic models.

  5. Graphs with constant μ and μ

    NARCIS (Netherlands)

    van Dam, E.R.; Haemers, W.H.

    1995-01-01

    A graph G has constant u = u(G) if any two vertices that are not adjacent have u common neighbours. G has constant u and u if G has constant u = u(G), and its complement G has constant u = u(G). If such a graph is regular, then it is strongly regular, otherwise precisely two vertex degrees occur. We

  6. Cosmological constant and curved 5D geometry

    CERN Document Server

    Ito, M

    2002-01-01

    We study the value of cosmological constant in de Sitter brane embedded in five dimensions with positive, vanishing and negative bulk cosmological constant. In the case of negative bulk cosmological constant, we show that not zero but tiny four-dimensional cosmological constant can be realized by tiny deviation from bulk curvature of the Randall-Sundrum model.

  7. Stability constant estimator user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Hay, B.P.; Castleton, K.J.; Rustad, J.R.

    1996-12-01

    The purpose of the Stability Constant Estimator (SCE) program is to estimate aqueous stability constants for 1:1 complexes of metal ions with ligands by using trends in existing stability constant data. Such estimates are useful to fill gaps in existing thermodynamic databases and to corroborate the accuracy of reported stability constant values.

  8. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    A.W. (Bert) Mulder; M.W. (Martijn) Hartog

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and

  9. Digital citizens Digital nations: the next agenda

    NARCIS (Netherlands)

    Mulder, A.W. (Bert); Hartog, M.W. (Martijn)

    2015-01-01

    DIGITAL CITIZENS CREATE A DIGITAL NATION Citizens will play the lead role as they – in the next phase of the information society – collectively create a digital nation. Personal adoption of information and communication technology will create a digital infrastructure that supports individual and col

  10. Constant training in direct ophthalmoscopy

    Directory of Open Access Journals (Sweden)

    Younan HC

    2017-08-01

    Full Text Available Helen-Cara Younan, Rishi Iyer, Janaki Natasha DesaiFaculty of Medicine, Imperial College London, London, UKWe read with great interest the review by Ricci and Ferraz on the advances in training and practice in ophthalmoscopy simulation.1As final year medical students, we have recently experienced direct ophthalmoscopy teaching and agree with the authors that “simulation is a helpful tool in ophthalmoscopy training”.1 Indeed, in our experience, simulation is useful in teaching a wide variety of clinical skills including venepuncture, intravenous cannulation, and catheterization. We were taught all of these clinical skills in our first clinical year of study through use of simulation models. With regards to our direct ophthalmoscopy teaching, we were first taught to recognize the normal retina and different retinal pathologies using images, before practicing our technique and recognition of those images in a model similar to the THELMA (The Human Eye Learning Model Assistant described by the authors.1However, we feel that the use of simulation models alone is not enough to provide confidence and competency in direct ophthalmoscopy among medical students. The authors conclude that “constant training is a well-known strategy for skill enhancement”,1 and we have found that a lack of constant training in direct ophthalmoscopy is evident. After learning venepuncture, cannulation, and catheterization on the simulation models, we were able to observe doctors performing these skills before performing them on patients either in the wards or in theatre. These are skills that we are constantly trained in across a wide variety of medical and surgical attachments. However, opportunities to observe and practice ophthalmoscopy during our attachments are more limited, and thus we are not continuing to use the skills we learn.Authors' replyLucas Holderegger Ricci,1 Caroline Amaral Ferraz21Department of Ophthalmology, School of Medicine, Laureate

  11. Application of multiple criteria decision making in the selection of digital forensics software

    OpenAIRE

    STANIVUKOVIC DEJAN R.; RANDJELOVIC DRAGAN M.

    2016-01-01

    Nowadays there is almost no criminal offense in the investigation of which digital evidence does not play a key role. Constant increase of the capacity of media that store digital data leads to continuous increase of the time necessary to identify and copy (acquire) digital evidence. Selection of appropriate digital forensics software is gaining in importance.Selection of adequate software includes a previous comparative analysis of two or more digital forensics software tools and an optimiza...

  12. Trends, discovery, and people in the digital age

    CERN Document Server

    Baker, David P

    2013-01-01

    Digital information is a constantly developing field. The first title in the Chandos Digital Information Review series, Trends, Discovery, and People in the Digital Age, summarises and presents key themes, advances and trends in all aspects of digital information today, exploring the impact of developing technologies on the information world. This book emphasises important contemporary topics and future developments from a global perspective. Dynamic contents by leaders in the field respond to what is happening in the field of digital information literacy, and anticipate future developments. T

  13. The fundamental constants a mystery of physics

    CERN Document Server

    Fritzsch, Harald

    2009-01-01

    The speed of light, the fine structure constant, and Newton's constant of gravity — these are just three among the many physical constants that define our picture of the world. Where do they come from? Are they constant in time and across space? In this book, physicist and author Harald Fritzsch invites the reader to explore the mystery of the fundamental constants of physics in the company of Isaac Newton, Albert Einstein, and a modern-day physicist

  14. Coupling constant in dispersive model

    Indian Academy of Sciences (India)

    R Saleh-Moghaddam; M E Zomorrodian

    2013-11-01

    The average of the moments for event shapes in + - → hadrons within the context of next-to-leading order (NLO) perturbative QCD prediction in dispersive model is studied. Moments used in this article are $\\langle 1 - T \\rangle, \\langle ρ \\rangle, \\langle B_{T} \\rangle$ and $\\langle B_{W} \\rangle$. We extract , the coupling constant in perturbative theory and α0 in the non-perturbative theory using the dispersive model. By fitting the experimental data, the values of $(M_{Z^{°}})$ = 0.1171 ± 0.00229 and 0 ($_{I} = 2{\\text{GeV}}$) = 0.5068 ± 0.0440 are found. Our results are consistent with the above model. Our results are also consistent with those obtained from other experiments at different energies. All these features are explained in this paper.

  15. Constant Proportion Debt Obligations (CPDOs)

    DEFF Research Database (Denmark)

    Cont, Rama; Jessen, Cathrine

    2012-01-01

    be made arbitrarily small—and thus the credit rating arbitrarily high—by increasing leverage, but the ratings obtained strongly depend on assumptions on the credit environment (high spread or low spread). More importantly, CPDO loss distributions are found to exhibit a wide range of tail risk measures......Constant Proportion Debt Obligations (CPDOs) are structured credit derivatives that generate high coupon payments by dynamically leveraging a position in an underlying portfolio of investment-grade index default swaps. CPDO coupons and principal notes received high initial credit ratings from...... the major rating agencies, based on complex models for the joint transition of ratings and spreads for all names in the underlying portfolio. We propose a parsimonious model for analysing the performance of CPDO strategies using a top-down approach that captures the essential risk factors of the CPDO. Our...

  16. Henry's law constants of polyols

    Directory of Open Access Journals (Sweden)

    S. Compernolle

    2014-12-01

    Full Text Available Henry's law constants (HLC are derived for several polyols bearing between 2 and 6 hydroxyl groups, based on literature data for water activity, vapour pressure and/or solubility. While deriving HLC and depending on the case, also infinite dilution activity coefficients (IDACs, solid state vapour pressures or activity coefficient ratios are obtained as intermediate results. An error analysis on the intermediate quantities and the obtained HLC is included. For most compounds, these are the first values reported, while others compare favourably with literature data in most cases. Using these values and those from a previous work (Compernolle and Müller, 2014, an assessment is made on the partitioning of polyols, diacids and hydroxy acids to droplet and aqueous aerosol.

  17. Omnidirectional antenna having constant phase

    Energy Technology Data Exchange (ETDEWEB)

    Sena, Matthew

    2017-04-04

    Various technologies presented herein relate to constructing and/or operating an antenna having an omnidirectional electrical field of constant phase. The antenna comprises an upper plate made up of multiple conductive rings, a lower ground-plane plate, a plurality of grounding posts, a conical feed, and a radio frequency (RF) feed connector. The upper plate has a multi-ring configuration comprising a large outer ring and several smaller rings of equal size located within the outer ring. The large outer ring and the four smaller rings have the same cross-section. The grounding posts ground the upper plate to the lower plate while maintaining a required spacing/parallelism therebetween.

  18. Fractional-order Systems and Synchronous Generator Voltage Regulator

    Directory of Open Access Journals (Sweden)

    Wojciech Lubośny

    2015-03-01

    Full Text Available Modern regulators of synchronous generators, including voltage regulators, are digital systems, in their vast majority with standard structures contained in the IEEE standard. These are systems described with stationary differential equations of integral order. Differential equations of fractional order are not employed in regulators for synchronous generator control. This paper presents an analysis of the possibilities of using a system of fractional differential equations in the voltage regulator of an synchronous generator with a static excitation system.

  19. Fractional-order Systems and Synchronous Generator Voltage Regulator

    OpenAIRE

    2015-01-01

    Modern regulators of synchronous generators, including voltage regulators, are digital systems, in their vast majority with standard structures contained in the IEEE standard. These are systems described with stationary differential equations of integral order. Differential equations of fractional order are not employed in regulators for synchronous generator control. This paper presents an analysis of the possibilities of using a system of fractional differential equations in the volta...

  20. Fractional calculus in bioengineering.

    Science.gov (United States)

    Magin, Richard L

    2004-01-01

    Fractional calculus (integral and differential operations of noninteger order) is not often used to model biological systems. Although the basic mathematical ideas were developed long ago by the mathematicians Leibniz (1695), Liouville (1834), Riemann (1892), and others and brought to the attention of the engineering world by Oliver Heaviside in the 1890s, it was not until 1974 that the first book on the topic was published by Oldham and Spanier. Recent monographs and symposia proceedings have highlighted the application of fractional calculus in physics, continuum mechanics, signal processing, and electromagnetics, but with few examples of applications in bioengineering. This is surprising because the methods of fractional calculus, when defined as a Laplace or Fourier convolution product, are suitable for solving many problems in biomedical research. For example, early studies by Cole (1933) and Hodgkin (1946) of the electrical properties of nerve cell membranes and the propagation of electrical signals are well characterized by differential equations of fractional order. The solution involves a generalization of the exponential function to the Mittag-Leffler function, which provides a better fit to the observed cell membrane data. A parallel application of fractional derivatives to viscoelastic materials establishes, in a natural way, hereditary integrals and the power law (Nutting/Scott Blair) stress-strain relationship for modeling biomaterials. In this review, I will introduce the idea of fractional operations by following the original approach of Heaviside, demonstrate the basic operations of fractional calculus on well-behaved functions (step, ramp, pulse, sinusoid) of engineering interest, and give specific examples from electrochemistry, physics, bioengineering, and biophysics. The fractional derivative accurately describes natural phenomena that occur in such common engineering problems as heat transfer, electrode/electrolyte behavior, and sub

  1. Social Trust and Fractionalization:

    DEFF Research Database (Denmark)

    Bjørnskov, Christian

    2008-01-01

    This paper takes a closer look at the importance of fractionalization for the creation of social trust. It first argues that the determinants of trust can be divided into two categories: those affecting individuals' trust radii and those affecting social polarization. A series of estimates using...... a much larger country sample than in previous literature confirms that fractionalization in the form of income inequality and political diversity adversely affects social trust while ethnic diversity does not. However, these effects differ systematically across countries, questioning standard...... interpretations of the influence of fractionalization on trust....

  2. Digital pathology

    CERN Document Server

    Sucaet, Yves

    2014-01-01

    Digital pathology has experienced exponential growth, in terms of its technology and applications, since its inception just over a decade ago. Though it has yet to be approved for primary diagnostics, its values as a teaching tool, facilitator of second opinions and quality assurance reviews and research are becoming, if not already, undeniable. It also offers the hope of providing pathology consultant and educational services to under-served areas, including regions of the world that could not possibly sustain this level of services otherwise. And this is just the beginning, as its adoption b

  3. Focus: Digital

    DEFF Research Database (Denmark)

    Technology has been an all-important and defining element within the arts throughout the 20th century, and it has fundamentally changed the ways in which we produce and consume music. With this Focus we investigate the latest developments in the digital domain – and their pervasiveness and rapid...... production and reception of contemporary music and sound art. With ‘Digital’ we present four composers' very different answers to how technology impact their work. To Juliana Hodkinson it has become an integral part of her sonic writing. Rudiger Meyer analyses the relationships between art and design and how...

  4. Discrete fractional calculus

    CERN Document Server

    Goodrich, Christopher

    2015-01-01

    This text provides the first comprehensive treatment of the discrete fractional calculus. Experienced researchers will find the text useful as a reference for discrete fractional calculus and topics of current interest. Students who are interested in learning about discrete fractional calculus will find this text to provide a useful starting point. Several exercises are offered at the end of each chapter and select answers have been provided at the end of the book. The presentation of the content is designed to give ample flexibility for potential use in a myriad of courses and for independent study. The novel approach taken by the authors includes a simultaneous treatment of the fractional- and integer-order difference calculus (on a variety of time scales, including both the usual forward and backwards difference operators). The reader will acquire a solid foundation in the classical topics of the discrete calculus while being introduced to exciting recent developments, bringing them to the frontiers of the...

  5. Fractional Derivative Cosmology

    CERN Document Server

    Roberts, Mark D

    2009-01-01

    The degree by which a function can be differentiated need not be restricted to integer values. Usually most of the field equations of physics are taken to be second order, curiosity asks what happens if this is only approximately the case and the field equations are nearly second order. For Robertson-Walker cosmology there is a simple fractional modification of the Friedman and conservation equations. In general fractional gravitational equations similar to Einstein's are hard to define as this requires fractional derivative geometry. What fractional derivative geometry might entail is briefly looked at and it turns out that even asking very simple questions in two dimensions leads to ambiguous or intractable results. A two dimensional line element which depends on the Gamma-function is looked at.

  6. Is There a Cosmological Constant?

    Science.gov (United States)

    Kochanek, Christopher

    2002-07-01

    The grant contributed to the publication of 18 refereed papers and 5 conference proceedings. The primary uses of the funding have been for page charges, travel for invited talks related to the grant research, and the support of a graduate student, Charles Keeton. The refereed papers address four of the primary goals of the proposal: (1) the statistics of radio lenses as a probe of the cosmological model (#1), (2) the role of spiral galaxies as lenses (#3), (3) the effects of dust on statistics of lenses (#7, #8), and (4) the role of groups and clusters as lenses (#2, #6, #10, #13, #15, #16). Four papers (#4, #5, #11, #12) address general issues of lens models, calibrations, and the relationship between lens galaxies and nearby galaxies. One considered cosmological effects in lensing X-ray sources (#9), and two addressed issues related to the overall power spectrum and theories of gravity (#17, #18). Our theoretical studies combined with the explosion in the number of lenses and the quality of the data obtained for them is greatly increasing our ability to characterize and understand the lens population. We can now firmly conclude both from our study of the statistics of radio lenses and our survey of extinctions in individual lenses that the statistics of optically selected quasars were significantly affected by extinction. However, the limits on the cosmological constant remain at lambda sigma confidence level, which is in mild conflict with the results of the Type la supernova surveys. We continue to find that neither spiral galaxies nor groups and clusters contribute significantly to the production of gravitational lenses. The lack of group and cluster lenses is strong evidence for the role of baryonic cooling in increasing the efficiency of galaxies as lenses compared to groups and clusters of higher mass but lower central density. Unfortunately for the ultimate objective of the proposal, improved constraints on the cosmological constant, the next large survey

  7. Intracellular Cadmium Isotope Fractionation

    Science.gov (United States)

    Horner, T. J.; Lee, R. B.; Henderson, G. M.; Rickaby, R. E.

    2011-12-01

    Recent stable isotope studies into the biological utilization of transition metals (e.g. Cu, Fe, Zn, Cd) suggest several stepwise cellular processes can fractionate isotopes in both culture and nature. However, the determination of fractionation factors is often unsatisfactory, as significant variability can exist - even between different organisms with the same cellular functions. Thus, it has not been possible to adequately understand the source and mechanisms of metal isotopic fractionation. In order to address this problem, we investigated the biological fractionation of Cd isotopes within genetically-modified bacteria (E. coli). There is currently only one known biological use or requirement of Cd, a Cd/Zn carbonic anhydrase (CdCA, from the marine diatom T. weissfloggii), which we introduce into the E. coli genome. We have also developed a cleaning procedure that allows for the treating of bacteria so as to study the isotopic composition of different cellular components. We find that whole cells always exhibit a preference for uptake of the lighter isotopes of Cd. Notably, whole cells appear to have a similar Cd isotopic composition regardless of the expression of CdCA within the E. coli. However, isotopic fractionation can occur within the genetically modified E. coli during Cd use, such that Cd bound in CdCA can display a distinct isotopic composition compared to the cell as a whole. Thus, the externally observed fractionation is independent of the internal uses of Cd, with the largest Cd isotope fractionation occurring during cross-membrane transport. A general implication of these experiments is that trace metal isotopic fractionation most likely reflects metal transport into biological cells (either actively or passively), rather than relating to expression of specific physiological function and genetic expression of different metalloenzymes.

  8. Application of the principal fractional meta-trigonometric functions for the solution of linear commensurate-order time-invariant fractional differential equations.

    Science.gov (United States)

    Lorenzo, C F; Hartley, T T; Malti, R

    2013-05-13

    A new and simplified method for the solution of linear constant coefficient fractional differential equations of any commensurate order is presented. The solutions are based on the R-function and on specialized Laplace transform pairs derived from the principal fractional meta-trigonometric functions. The new method simplifies the solution of such fractional differential equations and presents the solutions in the form of real functions as opposed to fractional complex exponential functions, and thus is directly applicable to real-world physics.

  9. Is There a Cosmological Constant?

    Science.gov (United States)

    Kochanek, Christopher; Oliversen, Ronald J. (Technical Monitor)

    2002-01-01

    The grant contributed to the publication of 18 refereed papers and 5 conference proceedings. The primary uses of the funding have been for page charges, travel for invited talks related to the grant research, and the support of a graduate student, Charles Keeton. The refereed papers address four of the primary goals of the proposal: (1) the statistics of radio lenses as a probe of the cosmological model (#1), (2) the role of spiral galaxies as lenses (#3), (3) the effects of dust on statistics of lenses (#7, #8), and (4) the role of groups and clusters as lenses (#2, #6, #10, #13, #15, #16). Four papers (#4, #5, #11, #12) address general issues of lens models, calibrations, and the relationship between lens galaxies and nearby galaxies. One considered cosmological effects in lensing X-ray sources (#9), and two addressed issues related to the overall power spectrum and theories of gravity (#17, #18). Our theoretical studies combined with the explosion in the number of lenses and the quality of the data obtained for them is greatly increasing our ability to characterize and understand the lens population. We can now firmly conclude both from our study of the statistics of radio lenses and our survey of extinctions in individual lenses that the statistics of optically selected quasars were significantly affected by extinction. However, the limits on the cosmological constant remain at lambda Labor and Munoz).

  10. A Variant of Davenport's Constant

    Indian Academy of Sciences (India)

    R Thangadurai

    2007-05-01

    Let be a prime number. Let be a finite abelian -group of exponent (written additively) and be a non-empty subset of $]n[:=\\{1,2,\\ldots,n\\}$ such that elements of are incongruent modulo and non-zero modulo . Let $k ≥ D(G)/|A|$ be any integer where () denotes the well-known Davenport’s constant. In this article, we prove that for any sequence $g_1,g_2,\\ldots,g_k$ (not necessarily distinct) in , one can always extract a subsequence $g_{i_1},g_{i_2},\\ldots,g_{i_l}$ with $1 ≤ l ≤ k$ such that $$\\sum\\limits_{j=1}^l a_j g_{i_j}=0 \\text{in} G,$$ where $a_j\\in A$ for all . We provide examples where this bound cannot be improved. Furthermore, for the cyclic groups, we prove some sharp results in this direction. In the last section, we explore the relation between this problem and a similar problem with prescribed length. The proof of Theorem 1 uses group-algebra techniques, while for the other theorems, we use elementary number theory techniques.

  11. The fundamental constants and quantum electrodynamics

    CERN Document Server

    Taylor, Barry N; Langenberg, D N

    1969-01-01

    Introduction ; review of experimental data ; least-squares adjustment to obtain values of the constants without QED theory ; implications for quantum electrodynamics ; final recommended set of fundamental constants ; summary and conclusions.

  12. Temporal variation of coupling constants and nucleosynthesis

    CERN Document Server

    Oberhummer, Heinz; Fairbairn, M; Schlattl, H; Sharma, M M

    2003-01-01

    We investigate the triple-alpha process and the Oklo phenomenon to obtain constraints on possible cosmological time variations of fundamental constants. Specifically we study cosmological temporal constraints for the fine structure constant and nucleon and meson masses.

  13. Capacitive Cells for Dielectric Constant Measurement

    Science.gov (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco

    2015-01-01

    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  14. Temporal variation of coupling constants and nucleosynthesis

    Science.gov (United States)

    Oberhummer, H.; Csótó, A.; Fairbairn, M.; Schlattl, H.; Sharma, M. M.

    2003-05-01

    We investigate the triple-alpha process and the Oklo phenomenon to obtain constraints on possible cosmological time variations of fundamental constants. Specifically we study cosmological temporal constraints for the fine structure constant and nucleon and meson masses.

  15. Capacitive Cells for Dielectric Constant Measurement

    Science.gov (United States)

    Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco

    2015-01-01

    A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

  16. New Fractional Complex Transform for Conformable Fractional Partial Differential Equations

    Directory of Open Access Journals (Sweden)

    Çenesiz Y.

    2016-12-01

    Full Text Available Conformable fractional complex transform is introduced in this paper for converting fractional partial differential equations to ordinary differential equations. Hence analytical methods in advanced calculus can be used to solve these equations. Conformable fractional complex transform is implemented to fractional partial differential equations such as space fractional advection diffusion equation and space fractional telegraph equation to obtain the exact solutions of these equations.

  17. Critical survey of stability constants of EDTA complexes critical evaluation of equilibrium constants in solution stability constants of metal complexes

    CERN Document Server

    Anderegg, G

    2013-01-01

    Critical Survey of Stability Constants of EDTA Complexes focuses on the computations, values, and characteristics of stability constants. The book emphasizes that for a critical discussion of experimentally determined stability constants, it is important to consider the precision of the values that manifests the self-consistency of the constant, taking into consideration the random errors. The publication reviews the stability constants of metal complexes. The numerical calculations affirm the reactions and transformations of metal ions when exposed to varying conditions. The text also present

  18. On k-Fibonacci Numbers with Applications to Continued Fractions

    Science.gov (United States)

    Rabago, Julius Fergy T.

    2016-02-01

    Let be the sequence of k-Fibonacci numbers recursively defined by and m be a fixed positive integer. In this work we prove that, for almost every x ɛ (0,1), the pattern k, k,..., k (comprising of m-digits) appears in the continued fraction expansion x = [0; a1,a2,. ..] with frequency where where

  19. Digital Humanities

    DEFF Research Database (Denmark)

    Nielsen, Hans Jørn

    2015-01-01

    overgangen fra trykkekultur til digital kultur. For det første problemstillingen omkring digitalisering af litterær kulturarv med fokus på kodning og tagging af teksten samt organisering i hypertekststrukturer. For det andet reorganiseringen af det digitale dokument i dataelementer og database. For det......, der betragter DH som forbundet med "making" og "building" af digitale objekter og former. Dette kan også karakteriseres som DH som praktisk-produktiv vending. Artiklen har valgt tre typer af digitalisering. De er valgt ud fra, at de skal repræsentere forskellige måder at håndtere digitaliseringen på...... og forskellige versioner af den praktisk-produktive vending. Artiklen undersøger tre typer digitalisering fra 1990erne til i dag ud fra denne optik. De repræsenterer forskellige former for approach til digitalisering og det digitale dokument og afspejler forskellige typer af problemstillinger i...

  20. Digital Avionics

    Science.gov (United States)

    Koelbl, Terry G.; Ponchak, Denise; Lamarche, Teresa

    2003-01-01

    Digital Avionics activities played an important role in the advancements made in civil aviation, military systems, and space applications. This document profiles advances made in each of these areas by the aerospace industry, NASA centers, and the U.S. military. Emerging communication technologies covered in this document include Internet connectivity onboard aircraft, wireless broadband communication for aircraft, and a mobile router for aircraft to communicate in multiple communication networks over the course of a flight. Military technologies covered in this document include avionics for unmanned combat air vehicles and microsatellites, and head-up displays. Other technologies covered in this document include an electronic flight bag for the Boeing 777, and surveillance systems for managing airport operations.

  1. Untangling Fixed Effects and Constant Regressors

    NARCIS (Netherlands)

    Klaassen, F.; Teulings, R.

    2015-01-01

    Fixed effects (FE) in panel data models overlap each other and prohibit the identification of the impact of "constant" regressors. Think of regressors that are constant across countries in a country-time panel with time FE. The traditional approach is to drop some FE and constant regressors by

  2. Untangling Fixed Effects and Constant Regressors

    NARCIS (Netherlands)

    Klaassen, F.; Teulings, R.

    2015-01-01

    Fixed effects (FE) in panel data models overlap each other and prohibit the identification of the impact of "constant" regressors. Think of regressors that are constant across countries in a country-time panel with time FE. The traditional approach is to drop some FE and constant regressors by norma

  3. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    2016-01-01

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the org

  4. Digital work in a digitally challenged organization

    NARCIS (Netherlands)

    Davison, R.M.; Ou, Carol

    Digitally literate employees are accustomed to having free access to digital media technologies. However, some organizations enact information technology (IT) governance structures that explicitly proscribe access to these technologies, resulting in considerable tension between employees and the

  5. Digital cover photography for estimating leaf area index (LAI) in apple trees using a variable light extinction coefficient.

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-28

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAI(D)), which was compared with LAI estimated by the proposed digital photography method (LAI(M)). Results showed that the LAI(M) was able to estimate LAI(D) with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (f(f)) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  6. Digital Cover Photography for Estimating Leaf Area Index (LAI) in Apple Trees Using a Variable Light Extinction Coefficient

    Science.gov (United States)

    Poblete-Echeverría, Carlos; Fuentes, Sigfredo; Ortega-Farias, Samuel; Gonzalez-Talice, Jaime; Yuri, Jose Antonio

    2015-01-01

    Leaf area index (LAI) is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io) and transmitted radiation (I) through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID), which was compared with LAI estimated by the proposed digital photography method (LAIM). Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68). However, when k was estimated using an exponential function based on the fraction of foliage cover (ff) derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic) were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions. PMID:25635411

  7. Digital Cover Photography for Estimating Leaf Area Index (LAI in Apple Trees Using a Variable Light Extinction Coefficient

    Directory of Open Access Journals (Sweden)

    Carlos Poblete-Echeverría

    2015-01-01

    Full Text Available Leaf area index (LAI is one of the key biophysical variables required for crop modeling. Direct LAI measurements are time consuming and difficult to obtain for experimental and commercial fruit orchards. Devices used to estimate LAI have shown considerable errors when compared to ground-truth or destructive measurements, requiring tedious site-specific calibrations. The objective of this study was to test the performance of a modified digital cover photography method to estimate LAI in apple trees using conventional digital photography and instantaneous measurements of incident radiation (Io and transmitted radiation (I through the canopy. Leaf area of 40 single apple trees were measured destructively to obtain real leaf area index (LAID, which was compared with LAI estimated by the proposed digital photography method (LAIM. Results showed that the LAIM was able to estimate LAID with an error of 25% using a constant light extinction coefficient (k = 0.68. However, when k was estimated using an exponential function based on the fraction of foliage cover (ff derived from images, the error was reduced to 18%. Furthermore, when measurements of light intercepted by the canopy (Ic were used as a proxy value for k, the method presented an error of only 9%. These results have shown that by using a proxy k value, estimated by Ic, helped to increase accuracy of LAI estimates using digital cover images for apple trees with different canopy sizes and under field conditions.

  8. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab MissionEstablish and maintain a Digital...

  9. USNA DIGITAL FORENSICS LAB

    Data.gov (United States)

    Federal Laboratory Consortium — To enable Digital Forensics and Computer Security research and educational opportunities across majors and departments. Lab Mission Establish and maintain a Digital...

  10. Digital Marketer: Facing Digital Marketing Opportunities

    OpenAIRE

    NEGRICEA, Costel Iliuta; PURCAREA, Ioan Matei

    2015-01-01

    We are witnessing the emergence of new ecosystems thanks to digital disruption, marketers being challenged to bring marketing operations into the digital era, enhance the customer journey and shift consumer behavior with the help of the digital tools, while actively encouraging feedback from users, and building a circle of trust with the company’s audience. Recent findings showed clear differences of consumers’ preferences and of what marketers say they’re doing with digital technology. Respo...

  11. Seismic pulse propagation with constant Q and stable probability distributions

    Directory of Open Access Journals (Sweden)

    M. Tomirotti

    1997-06-01

    Full Text Available The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with an index of stability determined by the order of the fractional time derivative in the evolution equation.

  12. Seismic pulse propagation with constant Q and stable probability distributions

    CERN Document Server

    Mainardi, Francesco

    2010-01-01

    The one-dimensional propagation of seismic waves with constant Q is shown to be governed by an evolution equation of fractional order in time, which interpolates the heat equation and the wave equation. The fundamental solutions for the Cauchy and Signalling problems are expressed in terms of entire functions (of Wright type) in the similarity variable and their behaviours turn out to be intermediate between those for the limiting cases of a perfectly viscous fluid and a perfectly elastic solid. In view of the small dissipation exhibited by the seismic pulses, the nearly elastic limit is considered. Furthermore, the fundamental solutions for the Cauchy and Signalling problems are shown to be related to stable probability distributions with index of stability determined by the order of the fractional time derivative in the evolution equation.

  13. Fractional Vortices and Lumps

    CERN Document Server

    Eto, Minoru; Gudnason, Sven Bjarke; Konishi, Kenichi; Nagashima, Takayuki; Nitta, Muneto; Ohashi, Keisuke; Vinci, Walter

    2009-01-01

    We study what might be called fractional vortices, vortex configurations with the minimum winding from the viewpoint of their topological stability, but which are characterized by various notable substructures in the transverse energy distribution. The fractional vortices occur in diverse Abelian or non-Abelian generalizations of the Higgs model. The global and local features characterizing these are studied, and we identify the two crucial ingredients for their occurrence - the vacuum degeneracy leading to non-trivial vacuum moduli M, and the BPS nature of the vortices. Fractional vortices are further classified into two kinds. The first type of such vortices appear when M has orbifold Z_n singularities; the second type occurs in systems in which the vacuum moduli space M possesses either a deformed geometry or some singularity. These general features are illustrated with several concrete models.

  14. Fractional-order devices

    CERN Document Server

    Biswas, Karabi; Caponetto, Riccardo; Mendes Lopes, António; Tenreiro Machado, José António

    2017-01-01

    This book focuses on two specific areas related to fractional order systems – the realization of physical devices characterized by non-integer order impedance, usually called fractional-order elements (FOEs); and the characterization of vegetable tissues via electrical impedance spectroscopy (EIS) – and provides readers with new tools for designing new types of integrated circuits. The majority of the book addresses FOEs. The interest in these topics is related to the need to produce “analogue” electronic devices characterized by non-integer order impedance, and to the characterization of natural phenomena, which are systems with memory or aftereffects and for which the fractional-order calculus tool is the ideal choice for analysis. FOEs represent the building blocks for designing and realizing analogue integrated electronic circuits, which the authors believe hold the potential for a wealth of mass-market applications. The freedom to choose either an integer- or non-integer-order analogue integrator...

  15. Fractional and noncommutative spacetimes

    Science.gov (United States)

    Arzano, Michele; Calcagni, Gianluca; Oriti, Daniele; Scalisi, Marco

    2011-12-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determining the log-period coincides with the nonrotation-invariant but cyclicity-preserving measure of κ-Minkowski spacetime. At scales larger than the log-period, the fractional measure is averaged and becomes a power law with real exponent. This can be also regarded as the cyclicity-inducing measure in a noncommutative spacetime defined by a certain nonlinear algebra of the coordinates, which interpolates between κ-Minkowski and canonical spacetime. These results are based upon a braiding formula valid for any nonlinear algebra which can be mapped onto the Heisenberg algebra.

  16. Fractional and noncommutative spacetimes

    CERN Document Server

    Arzano, Michele; Oriti, Daniele; Scalisi, Marco

    2011-01-01

    We establish a mapping between fractional and noncommutative spacetimes in configuration space. Depending on the scale at which the relation is considered, there arise two possibilities. For a fractional spacetime with log-oscillatory measure, the effective measure near the fundamental scale determining the log-period coincides with the non-rotation-invariant but cyclicity-preserving measure of \\kappa-Minkowski. At scales larger than the log-period, the fractional measure is averaged and becomes a power-law with real exponent. This can be also regarded as the cyclicity-inducing measure in a noncommutative spacetime defined by a certain nonlinear algebra of the coordinates, which interpolates between \\kappa-Minkowski and canonical spacetime. These results are based upon a braiding formula valid for any nonlinear algebra which can be mapped onto the Heisenberg algebra.

  17. Can We Teach Digital Natives Digital Literacy?

    Science.gov (United States)

    Ng, Wan

    2012-01-01

    In recent years, there has been much debate about the concept of digital natives, in particular the differences between the digital natives' knowledge and adoption of digital technologies in informal versus formal educational contexts. This paper investigates the knowledge about educational technologies of a group of undergraduate students…

  18. Preparation of Porous Silica Ceramics with Low Dielectric Constant

    Institute of Scientific and Technical Information of China (English)

    MAO Xiao-jian; WANG Shi-wei; SHIMAI Shun-zo

    2006-01-01

    Porous silica ceramics has been prepared with the starch consolidation casting method. Slurries with various fractions of starch added in were prepared by ball-milling. The evaluation of the microstructures was done through two techniques: Hg porosimetry and SEM investigation. The bending strength of the sintered samples varied within the range of 10 MPa-20 MPa and the low dielectric constant within the range of 2.0-2.4 correspondent with the porosity of 42%-56%. The ceramics holds a brilliant promise of being a kind of core material used in sandwich-like electromagnetic windows.

  19. Fractional standard map

    Energy Technology Data Exchange (ETDEWEB)

    Edelman, Mark, E-mail: edelman@cims.nyu.ed [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012 (United States)] [Department of Physics, Stern College at Yeshiva University, 245 Lexington Avenue, New York, NY 10016 (United States); Tarasov, Vasily E. [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St., New York, NY 10012 (United States)] [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119991 (Russian Federation)

    2009-12-28

    Properties of the phase space of the standard map with memory are investigated. This map was obtained from a kicked fractional differential equation. Depending on the value of the map parameter and the fractional order of the derivative in the original differential equation, this nonlinear dynamical system demonstrates attractors (fixed points, stable periodic trajectories, slow converging and slow diverging trajectories, ballistic trajectories, and fractal-like structures) and/or chaotic trajectories. At least one type of fractal-like sticky attractors in the chaotic sea was observed.

  20. Image restoration based on the discrete fraction Fourier transform

    Science.gov (United States)

    Yan, Peimin; Mo, Yu L.; Liu, Hong

    2001-09-01

    The fractional Fourier transform is the powerful tool for time-variant signal analysis. For space-variant degradation and non-stationary processes the filtering in fractional Fourier domains permits reduction of the error compared with ordinary Fourier domain filtering. In this paper the concept of filtering in fractional Fourier domains is applied to the problem of estimating degraded images. Efficient digital implementation using discrete Hermite eigenvectors can provide similar results to match the continuous outputs. Expressions for the 2D optimal filter function in fractional domains will be given for transform domains characterized by the two rotation angle parameters of the 2D fractional Fourier transform. The proposed method is used to restore images that have several degradations in the experiments. The results show that the method presented in this paper is valid.

  1. Fractional order differentiation by integration with Jacobi polynomials

    KAUST Repository

    Liu, Dayan

    2012-12-01

    The differentiation by integration method with Jacobi polynomials was originally introduced by Mboup, Join and Fliess [22], [23]. This paper generalizes this method from the integer order to the fractional order for estimating the fractional order derivatives of noisy signals. The proposed fractional order differentiator is deduced from the Jacobi orthogonal polynomial filter and the Riemann-Liouville fractional order derivative definition. Exact and simple formula for this differentiator is given where an integral formula involving Jacobi polynomials and the noisy signal is used without complex mathematical deduction. Hence, it can be used both for continuous-time and discrete-time models. The comparison between our differentiator and the recently introduced digital fractional order Savitzky-Golay differentiator is given in numerical simulations so as to show its accuracy and robustness with respect to corrupting noises. © 2012 IEEE.

  2. Robust fractional order differentiators using generalized modulating functions method

    KAUST Repository

    Liu, Dayan

    2015-02-01

    This paper aims at designing a fractional order differentiator for a class of signals satisfying a linear differential equation with unknown parameters. A generalized modulating functions method is proposed first to estimate the unknown parameters, then to derive accurate integral formulae for the left-sided Riemann-Liouville fractional derivatives of the studied signal. Unlike the improper integral in the definition of the left-sided Riemann-Liouville fractional derivative, the integrals in the proposed formulae can be proper and be considered as a low-pass filter by choosing appropriate modulating functions. Hence, digital fractional order differentiators applicable for on-line applications are deduced using a numerical integration method in discrete noisy case. Moreover, some error analysis are given for noise error contributions due to a class of stochastic processes. Finally, numerical examples are given to show the accuracy and robustness of the proposed fractional order differentiators.

  3. Análise da resposta em regime transitório e permanente de algoritmos para filtragem digital utilizados em relés numéricos: velocidade de convergência, overshoot e sensibilidade em relação a constante de tempo

    OpenAIRE

    Machado,Tatiane Martins; Cardoso Jr,Ghendy; Stefanello,Nilvania; Morais,Adriano Peres de; Mariotto,Lenois

    2011-01-01

    Este trabalho visa avaliar o desempenho de algoritmos de filtragem digital para relés numéricos em termos da capacidade de rejeição da componente DC, resposta transitória, exatidão, freqüência de amostragem e imunidade a ruídos. Além dos filtros clássicos de Fourier de ciclo completo e Cosseno também, são consideradas duas Transformadas Discretas de Fourier (TDF) modificadas. Os sinais de corrente utilizados nos testes foram gerados por equações matemáticas e por simulações computacionais em ...

  4. Building the Foundations and Enterprise Capabilities for Digital Leadership

    DEFF Research Database (Denmark)

    El Sawy, Omar; Kræmmergaard, Pernille; Amsinck, Henrik

    2015-01-01

    -and-mortar companies to be competitively successful in this new dynamic environment, a major organizational transformation for digitalization is needed and critical. While such transformations are not unusual, it is less clear how an enterprise can effectively build the foundations and nurture the path to enterprise......Every enterprise in every industry sooner or later finds itself in the midst of a digitally-intensive business ecosystem with emerging digital platforms, a growing demand for increasingly digital products and services, and constantly connected customers, partners, and employees. For legacy brick...... digital leadership as they undergo large organizational transformations and position themselves for the future. We define digital leadership for the enterprise as doing the right things for the strategic success of digitalization for the enterprise and its business ecosystem. How does an enterprise...

  5. Define Digital Vernacular

    Institute of Scientific and Technical Information of China (English)

    刘佳; 李海英; James Stevens; Rough Nelson

    2014-01-01

    As science and technology developed, the tools of humans developed from humans’hands, to mechanical and digital technologies. The tools influ-ence almost everything in the humans’world, so does vernacular. The digital vernacular could be understood as using digital technology to vernacular; the digital means technologies. It also could be understood as doing vernacular in a digital way;the digital means data and information, in other words it can be seeking truth from facts. Define digital vernacular is not only what is digital vernacular, but also about how to do the digital vernacular and what kind of attitude we should hold to-ward the digital vernacular. Define digital vernacular as both thinking and doing.

  6. Digital Immigrants and Digital Natives: Learning Business Informatics at Higher Educational Level

    Directory of Open Access Journals (Sweden)

    Suša Dalia

    2014-09-01

    Full Text Available Background: The term digital natives refer to those born since the 1980s and have been growing up surrounded by technology. On the other hand, digital immigrants are born before 1980s and learned how to use technology later in life. Objectives: Goal of the paper is to explore attitudes of digital native students on the course of Business Informatics at higher educational institutions (HEIs, and to compare them with attitudes of digital immigrants. Methods/Approach: The survey was conducted in 2014 using the sample of first-year Business Informatics students from the Faculty of Economics and Business in Zagreb, Croatia. Results were compared with a research conducted in 1998. Results: In comparison to an earlier research, digital natives perceive their level of competency in the subject of Business Informatics before teaching practices much higher compared to digital immigrants. However, there is still an increase in digital native students’ level of competency in the subject before and after teaching practices. Conclusions: The research confirms a shift from digital immigrants to digital natives who show high level of interest for Business Informatics course topics and find its utility very high. However, constant improvement of delivering knowledge is needed in order to keep these high levels.

  7. From Complex Fractional Fourier Transform to Complex Fractional Radon Transform

    Institute of Scientific and Technical Information of China (English)

    FAN Hong-Yi; JIANG Nian-Quan

    2004-01-01

    We show that for n-dimensional complex fractional Fourier transform the corresponding complex fractional Radon transform can also be derived, however, it is different from the direct product of two n-dimensional real fractional Radon transforms. The complex fractional Radon transform of two-mode Wigner operator is calculated.

  8. Digital forensics digital evidence in criminal investigations

    CERN Document Server

    Marshall, Angus McKenzie

    2009-01-01

    The vast majority of modern criminal investigations involve some element of digital evidence, from mobile phones, computers, CCTV and other devices. Digital Forensics: Digital Evidence in Criminal Investigations provides the reader with a better understanding of how digital evidence complements "traditional" scientific evidence and examines how it can be used more effectively and efficiently in a range of investigations. Taking a new approach to the topic, this book presents digital evidence as an adjunct to other types of evidence and discusses how it can be deployed effectively in s

  9. Avoidance of Fractions.

    Science.gov (United States)

    Hart, Kathleen; Kerslake, Daphne

    The Concepts in Secondary Mathematics and Science (CSMS) and Strategies and Errors in Secondary Mathematics (SESM) research projects based at Chelsa College, England, have shown the marked reluctance of secondary school students to use fractions when solving mathematical problems, even though they have been taught the topic for a number of years.…

  10. Brewing with fractionated barley

    NARCIS (Netherlands)

    Donkelaar, van L.H.G.

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw

  11. Ramping up on Fractions

    Science.gov (United States)

    Stephens, Ana C.; Bottge, Brian A.; Rueda, Enrique

    2009-01-01

    This article describes a technology-based and hands-on instructional intervention designed to advance middle school students' understandings of fractions. This problem-solving experience is based on the principles of Enhanced Anchored Instruction (EAI) and proved instructionally worthwhile and motivating to teachers and students in both inclusive …

  12. Sweet Work with Fractions

    Science.gov (United States)

    Vinogradova, Natalya; Blaine, Larry

    2013-01-01

    Almost everyone loves chocolate. However, the same cannot be said about fractions, which are loved by markedly fewer. Middle school students tend to view them with wary respect, but little affection. The authors attempt to sweeten the subject by describing a type of game involving division of chocolate bars. The activity they describe provides a…

  13. Momentum fractionation on superstrata

    Science.gov (United States)

    Bena, Iosif; Martinec, Emil; Turton, David; Warner, Nicholas P.

    2016-05-01

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in high-degree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Our construction establishes the very nontrivial fact that large classes of CFT states with momentum fractionation can be realized in the bulk as smooth horizonless supergravity solutions.

  14. Fractional statistics and confinement

    CERN Document Server

    Gaete, P; Gaete, Patricio; Wotzasek, Clovis

    2004-01-01

    It is shown that a pointlike composite having charge and magnetic moment displays a confining potential for the static interaction while simultaneously obeying fractional statistics in a pure gauge theory in three dimensions, without a Chern-Simons term. This result is distinct from the Maxwell-Chern-Simons theory that shows a screening nature for the potential.

  15. Brewing with fractionated barley

    NARCIS (Netherlands)

    Donkelaar, van L.H.G.

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw

  16. Fractional Differential Equation

    Directory of Open Access Journals (Sweden)

    Moustafa El-Shahed

    2007-01-01

    where 2<α<3 is a real number and D0+α is the standard Riemann-Liouville fractional derivative. Our analysis relies on Krasnoselskiis fixed point theorem of cone preserving operators. An example is also given to illustrate the main results.

  17. On-line structure-lossless digital mammogram image compression

    Science.gov (United States)

    Wang, Jun; Huang, H. K.

    1996-04-01

    This paper proposes a novel on-line structure lossless compression method for digital mammograms during the film digitization process. The structure-lossless compression segments the breast and the background, compresses the former with a predictive lossless coding method and discards the latter. This compression scheme is carried out during the film digitization process and no additional time is required for the compression. Digital mammograms are compressed on-the-fly while they are created. During digitization, lines of scanned data are first acquired into a small temporary buffer in the scanner, then they are transferred to a large image buffer in an acquisition computer which is connected to the scanner. The compression process, running concurrently with the digitization process in the acquisition computer, constantly checks the image buffer and compresses any newly arrived data. Since compression is faster than digitization, data compression is completed as soon as digitization is finished. On-line compression during digitization does not increase overall digitizing time. Additionally, it reduces the mammogram image size by a factor of 3 to 9 with no loss of information. This algorithm has been implemented in a film digitizer. Statistics were obtained based on digitizing 46 mammograms at four sampling distances from 50 to 200 microns.

  18. Digital dannelse

    DEFF Research Database (Denmark)

    Bundsgaard, Jeppe

    2012-01-01

    I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et dannelsesspørgs......I al vores iver efter at få presset nogle flere digitale dimser ind i skolen, er vi i fare for at glemme hvad det er vi skal med disse dimser. Der er store forventninger til at de kan gøre det lettere at være lærer (og dermed billigere), og det kan det måske. Men der er jo også et...... dannelsesspørgsmål knyttet til it. Hvad er egentlig digital dannelse? Og hvad betyder det for danskfaget?...

  19. Digital platforms as enablers for digital transformation

    DEFF Research Database (Denmark)

    Hossain, Mokter; Lassen, Astrid Heidemann

    2017-01-01

    Digital platforms offer new ways for organizations to collaborate with the external environment for ideas, technologies, and knowledge. They provide new possibilities and competence but they also bring new challenges for organizations. Understanding the role of these platforms in digital...... transformation is crucial. This study aims at exploring how organizations are driven towards transformation in various ways to embrace digital platforms for ideas, technologies, and knowledge. It shows the opportunities and challenges digital platforms bring in organizations. It also highlights underlying...... mechanisms and potential outcomes of various digital platforms. The contribution of the submission is valuable for scholars to understand and further explore this area. It provides insight for practitioners to capture value through digital platforms and accelerate the pace of organizations’ digital...

  20. The Influence of Uncompensated Solution Resistance on the Determination and Standard Electrochemical Rate Constants Using Cyclic Voltammetry, and Some Comparisons with AC Voltammetry.

    Science.gov (United States)

    1987-09-25

    rate constants, k2r using cyclic voltametry . The res tss are expressed in terms of systematic deviations oP sapparent measured" rate constants, k~b(app...Classification) The Influence of Uncompensated Solution Resistance on the Determination and Standard Electro- - . chemical Rate Constants Using Cyclic ...Year MonhOy SAGE COUNT FIELD GROUP Sue-GROUP digital simulation analysis, uncompensated solution resis- I A tance, electrochemical rate constants, cyclic

  1. H. Sapiens Digital: From Digital Immigrants and Digital Natives to Digital Wisdom

    Science.gov (United States)

    Prensky, Marc

    2009-01-01

    As we move further into the 21st century, the digital native/digital immigrant paradigm created by Marc Prensky in 2001 is becoming less relevant. In this article, Prensky suggests that we should focus instead on the development of what he calls "digital wisdom." Arguing that digital technology can make us not just smarter but truly wiser, Prensky…

  2. Creating, Naming, and Justifying Fractions

    Science.gov (United States)

    Siebert, Daniel; Gaskin, Nicole

    2006-01-01

    For students to develop meaningful conceptions of fractions and fraction operations, they need to think of fractions in terms other than as just whole-number combinations. In this article, we suggest two powerful images for thinking about fractions that move beyond whole-number reasoning. (Contains 5 figures.)

  3. Enabling Digital Literacy

    DEFF Research Database (Denmark)

    Ryberg, Thomas; Georgsen, Marianne

    2010-01-01

    There are some tensions between high-level policy definitions of “digital literacy” and actual teaching practice. We need to find workable definitions of digital literacy; obtain a better understanding of what digital literacy might look like in practice; and identify pedagogical approaches, which......, these operate on a meso-level mediating between high-level concepts of digital literacy and classroom practice....... support teachers in designing digital literacy learning. We suggest that frameworks such as Problem Based Learning (PBL) are approaches that enable digital literacy learning because they provide good settings for engaging with digital literacy. We illustrate this through analysis of a case. Furthermore...

  4. -Dimensional Fractional Lagrange's Inversion Theorem

    Directory of Open Access Journals (Sweden)

    F. A. Abd El-Salam

    2013-01-01

    Full Text Available Using Riemann-Liouville fractional differential operator, a fractional extension of the Lagrange inversion theorem and related formulas are developed. The required basic definitions, lemmas, and theorems in the fractional calculus are presented. A fractional form of Lagrange's expansion for one implicitly defined independent variable is obtained. Then, a fractional version of Lagrange's expansion in more than one unknown function is generalized. For extending the treatment in higher dimensions, some relevant vectors and tensors definitions and notations are presented. A fractional Taylor expansion of a function of -dimensional polyadics is derived. A fractional -dimensional Lagrange inversion theorem is proved.

  5. Non-Relativistic Spacetimes with Cosmological Constant

    OpenAIRE

    Aldrovandi, R.; Barbosa, A. L.; Crispino, L.C.B.; Pereira, J. G.

    1998-01-01

    Recent data on supernovae favor high values of the cosmological constant. Spacetimes with a cosmological constant have non-relativistic kinematics quite different from Galilean kinematics. De Sitter spacetimes, vacuum solutions of Einstein's equations with a cosmological constant, reduce in the non-relativistic limit to Newton-Hooke spacetimes, which are non-metric homogeneous spacetimes with non-vanishing curvature. The whole non-relativistic kinematics would then be modified, with possible ...

  6. Cosmological constant and Brane New World

    CERN Document Server

    Nojiri, S; Odintsov, S D; Nojiri, Shin'ichi; Obregon, Octavio; Odintsov, Sergei D.

    2001-01-01

    The estimation of the cosmological constant in inflationary Brane New World models is done. It is shown that basically it is quite large, of the same order as in anomaly-driven inflation. However, for some fine-tuning of bulk gravitational constant and AdS scale parameter $l^2$ it may be reduced to sufficiently small value. Bulk higher derivative AdS gravity with quantum brane matter may also serve as the model where small positive cosmological constant occurs.

  7. Singularities in universes with negative cosmological constant

    Energy Technology Data Exchange (ETDEWEB)

    Tipler, F.J.

    1976-10-01

    It is well known that many universes with negative cosmological constant contain singularities. We shall generalize this result by proving that all closed universes with negative cosmological constant are both future and past timelike geodesically incomplete if the strong energy condition holds. No global causality conditions or restrictions on the initial data are used in the proof. Furthermore, we shall show that all open universes with a Cauchy surface and a negative cosmological constant are singular if the strong energy condition holds. (AIP)

  8. Coasting cosmologies with time dependent cosmological constant

    CERN Document Server

    Pimentel, L O; Pimentel, Luis O.

    1999-01-01

    The effect of a time dependent cosmological constant is considered in a family of scalar tensor theories. Friedmann-Robertson-Walker cosmological models for vacumm and perfect fluid matter are found. They have a linear expansion factor, the so called coasting cosmology, the gravitational "constant" decreace inversely with time; this model satisfy the Dirac hipotesis. The cosmological "constant" decreace inversely with the square of time, therefore we can have a very small value for it at present time.

  9. On a time varying fine structure constant

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2001-01-01

    By employing Dirac LNH, and a further generalization by Berman (GLNH), we estimate how should vary the total number of nucleons, the energy density, Newton Gravitational constant, the cosmological constant, the magnetic permeability and electric permitivity, of the Universe,in order to account for the experimentally observed time variation of the fine structure constant. As a bonus,we find an acceptable value for the deceleration parameter of the present Universe, compatible with the Supernovae observations.

  10. Digital Sensor Technology

    Energy Technology Data Exchange (ETDEWEB)

    Ted Quinn; Jerry Mauck; Richard Bockhorst; Ken Thomas

    2013-07-01

    The nuclear industry has been slow to incorporate digital sensor technology into nuclear plant designs due to concerns with digital qualification issues. However, the benefits of digital sensor technology for nuclear plant instrumentation are substantial in terms of accuracy, reliability, availability, and maintainability. This report demonstrates these benefits in direct comparisons of digital and analog sensor applications. It also addresses the qualification issues that must be addressed in the application of digital sensor technology.

  11. Digital signal processing: Handbook

    Science.gov (United States)

    Goldenberg, L. M.; Matiushkin, B. D.; Poliak, M. N.

    The fundamentals of the theory and design of systems and devices for the digital processing of signals are presented. Particular attention is given to algorithmic methods of synthesis and digital processing equipment in communication systems (e.g., selective digital filtering, spectral analysis, and variation of the signal discretization frequency). Programs for the computer-aided analysis of digital filters are described. Computational examples are presented, along with tables of transfer function coefficients for recursive and nonrecursive digital filters.

  12. Digital preservation for heritages

    CERN Document Server

    Lu, Dongming

    2011-01-01

    ""Digital Preservation for Heritages: Technologies and Applications"" provides a comprehensive and up-to-date coverage of digital technologies in the area of cultural heritage preservation, including digitalization, research aiding, conservation aiding, digital exhibition, and digital utilization. Processes, technical frameworks, key technologies, as well as typical systems and applications are discussed in the book. It is intended for researchers and students in the fields of computer science and technology, museology, and archaeology. Dr. Dongming Lu is a professor at College of Computer Sci

  13. Characteristics of Digital Sustainability

    OpenAIRE

    Stuermer, Matthias

    2014-01-01

    The concept of digital sustainability is mentioned in research on digital preservation as well as on openness topics. Both streams of literature point out the necessary discussion how to create, use, and regulate digital resources in order to maximize their value for our society today and in the future. This paper therefore reviews current work on digital sustainability, presents a list of six charac-teristics how to define digitally sustainable goods, and draws the link to aspects of e-gover...

  14. A natural cosmological constant from chameleons

    Directory of Open Access Journals (Sweden)

    Horatiu Nastase

    2015-07-01

    Full Text Available We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero and the coincidence problem (why Λ is comparable to the matter density now.

  15. Surprises in numerical expressions of physical constants

    CERN Document Server

    Amir, Ariel; Tokieda, Tadashi

    2016-01-01

    In science, as in life, `surprises' can be adequately appreciated only in the presence of a null model, what we expect a priori. In physics, theories sometimes express the values of dimensionless physical constants as combinations of mathematical constants like pi or e. The inverse problem also arises, whereby the measured value of a physical constant admits a `surprisingly' simple approximation in terms of well-known mathematical constants. Can we estimate the probability for this to be a mere coincidence, rather than an inkling of some theory? We answer the question in the most naive form.

  16. A natural cosmological constant from chameleons

    Energy Technology Data Exchange (ETDEWEB)

    Nastase, Horatiu, E-mail: nastase@ift.unesp.br [Instituto de Física Teórica, UNESP-Universidade Estadual Paulista, R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Weltman, Amanda, E-mail: amanda.weltman@uct.ac.za [Astrophysics, Cosmology & Gravity Center, Department of Mathematics and Applied Mathematics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa)

    2015-07-30

    We present a simple model where the effective cosmological constant appears from chameleon scalar fields. For a Kachru–Kallosh–Linde–Trivedi (KKLT)-inspired form of the potential and a particular chameleon coupling to the local density, patches of approximately constant scalar field potential cluster around regions of matter with density above a certain value, generating the effect of a cosmological constant on large scales. This construction addresses both the cosmological constant problem (why Λ is so small, yet nonzero) and the coincidence problem (why Λ is comparable to the matter density now)

  17. Fractional lattice charge transport

    Science.gov (United States)

    Flach, Sergej; Khomeriki, Ramaz

    2017-01-01

    We consider the dynamics of noninteracting quantum particles on a square lattice in the presence of a magnetic flux α and a dc electric field E oriented along the lattice diagonal. In general, the adiabatic dynamics will be characterized by Bloch oscillations in the electrical field direction and dispersive ballistic transport in the perpendicular direction. For rational values of α and a corresponding discrete set of values of E(α) vanishing gaps in the spectrum induce a fractionalization of the charge in the perpendicular direction - while left movers are still performing dispersive ballistic transport, the complementary fraction of right movers is propagating in a dispersionless relativistic manner in the opposite direction. Generalizations and the possible probing of the effect with atomic Bose-Einstein condensates and photonic networks are discussed. Zak phase of respective band associated with gap closing regime has been computed and it is found converging to π/2 value. PMID:28102302

  18. Fractions in elementary education

    CERN Document Server

    Quinn, Frank

    2013-01-01

    This paper is one of a series in which elementary-education practice is analyzed by comparison with the history of mathematics, mathematical structure, modern practice, and (occasionally) cognitive neuroscience. The primary concerns are: Why do so many children find elementary mathematics difficult? And, why are the ones who succeed still so poorly prepared for college material needed for technical careers? The answer provided by conventional wisdom is essentially that mathematics is difficult. Third-graders are not developmentally ready for the subtlety of fractions, for instance, and even high-performing students cannot be expected to develop the skills of experienced users. However we will see that this is far from the whole story and is probably wrong: elementary-education fractions are genuinely harder and less effective than the version employed by experienced users. Experts discard at least 90% of what is taught in schools. Our educational system is actually counterproductive for skill development, and...

  19. Testing Fractional Action Cosmology

    CERN Document Server

    Shchigolev, V K

    2015-01-01

    The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests that gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.

  20. Testing fractional action cosmology

    Science.gov (United States)

    Shchigolev, V. K.

    2016-08-01

    The present work deals with a combined test of the so-called Fractional Action Cosmology (FAC) on the example of a specific model obtained by the author earlier. In this model, the effective cosmological term is proportional to the Hubble parameter squared through the so-called kinematic induction. The reason of studying this cosmological model could be explained by its ability to describe two periods of accelerated expansion, that is in agreement with the recent observations and the cosmological inflation paradigm. First of all, we put our model through the theoretical tests, which gives a general conception of the influence of the model parameters on its behavior. Then, we obtain some restrictions on the principal parameters of the model, including the fractional index, by means of the observational data. Finally, the cosmography parameters and the observational data compared to the theoretical predictions are presented both analytically and graphically.

  1. Fractional Power Control for Decentralized Wireless Networks

    CERN Document Server

    Jindal, Nihar; Andrews, Jeffrey G

    2007-01-01

    We propose and analyze a new paradigm for power control in decentralized wireless networks, termed fractional power control. Transmission power is chosen as the current channel quality raised to an exponent -s, where s is a constant between 0 and 1. Choosing s = 1 and s = 0 correspond to the familiar cases of channel inversion and constant power transmission, respectively. Choosing s in (0, 1) allows all intermediate policies between these two extremes to be evaluated, and we see that neither extreme is ideal. We prove that using an exponent of s = 1/2 optimizes the transmission capacity of an ad hoc network, meaning that the inverse square root of the channel strength is the optimal transmit power scaling. Intuitively, this choice achieves the optimal balance between helping disadvantaged users while making sure they do not flood the network with interference.

  2. Nonlinear fractional relaxation

    Indian Academy of Sciences (India)

    A Tofighi

    2012-04-01

    We define a nonlinear model for fractional relaxation phenomena. We use -expansion method to analyse this model. By studying the fundamental solutions of this model we find that when → 0 the model exhibits a fast decay rate and when → ∞ the model exhibits a power-law decay. By analysing the frequency response we find a logarithmic enhancement for the relative ratio of susceptibility.

  3. Brewing with fractionated barley

    OpenAIRE

    Donkelaar, van, CC René

    2016-01-01

    Brewing with fractionated barley Beer is a globally consumed beverage, which is produced from malted barley, water, hops and yeast. In recent years, the use of unmalted barley and exogenous enzymes have become more popular because they enable simpler processing and reduced environmental impact. Raw barley, however, contains less endogenous enzymes and more undesired components for the use of beer brewing, compared to malted barley.  The overall aim of this thesis is to investigate how ba...

  4. Momentum Fractionation on Superstrata

    CERN Document Server

    Bena, Iosif; Turton, David; Warner, Nicholas P

    2016-01-01

    Superstrata are bound states in string theory that carry D1, D5, and momentum charges, and whose supergravity descriptions are parameterized by arbitrary functions of (at least) two variables. In the D1-D5 CFT, typical three-charge states reside in high-degree twisted sectors, and their momentum charge is carried by modes that individually have fractional momentum. Understanding this momentum fractionation holographically is crucial for understanding typical black-hole microstates in this system. We use solution-generating techniques to add momentum to a multi-wound supertube and thereby construct the first examples of asymptotically-flat superstrata. The resulting supergravity solutions are horizonless and smooth up to well-understood orbifold singularities. Upon taking the AdS3 decoupling limit, our solutions are dual to CFT states with momentum fractionation. We give a precise proposal for these dual CFT states. Our construction establishes the very nontrivial fact that large classes of CFT states with mom...

  5. On the origins of generalized fractional calculus

    Science.gov (United States)

    Kiryakova, Virginia

    2015-11-01

    In Fractional Calculus (FC), as in the (classical) Calculus, the notions of derivatives and integrals (of first, second, etc. or arbitrary, incl. non-integer order) are basic and co-related. One of the most frequent approach in FC is to define first the Riemann-Liouville (R-L) integral of fractional order, and then by means of suitable integer-order differentiation operation applied over it (or under its sign) a fractional derivative is defined - in the R-L sense (or in Caputo sense). The first mentioned (R-L type) is closer to the theoretical studies in analysis, but has some shortages - from the point of view of interpretation of the initial conditions for Cauchy problems for fractional differential equations (stated also by means of fractional order derivatives/ integrals), and also for the analysts' confusion that such a derivative of a constant is not zero in general. The Caputo (C-) derivative, arising first in geophysical studies, helps to overcome these problems and to describe models of applied problems with physically consistent initial conditions. The operators of the Generalized Fractional Calculus - GFC (integrals and derivatives) are based on commuting m-tuple (m = 1, 2, 3, …) compositions of operators of the classical FC with power weights (the so-called Erdélyi-Kober operators), but represented in compact and explicit form by means of integral, integro-differential (R-L type) or differential-integral (C-type) operators, where the kernels are special functions of most general hypergeometric kind. The foundations of this theory are given in Kiryakova 18. In this survey we present the genesis of the definitions of the GFC - the generalized fractional integrals and derivatives (of fractional multi-order) of R-L type and Caputo type, analyze their properties and applications. Their special cases are all the known operators of classical FC, their generalizations introduced by other authors, the hyper-Bessel differential operators of higher integer

  6. Composite fermions for fractionally filled Chern bands

    Science.gov (United States)

    Shankar, R.

    2012-02-01

    We consider fractionally filled bands with a non-zero Chern index that exhibit the Fractional Quantum Hall Effect in zero external fieldootnotetextR. Roy and S. Sondhi, Physics 4, 46 (2011) and papers reviewed therein. a possibility supported by numerical work.ootnotetextIbid. Analytic treatments are complicated by a non-constant Berry flux and the absence of Composite Fermions (CF), which would not only single out preferred fractions, but also allow us compute numerous response functions at nonzero frequencies, wavelengths and temperature using either Chern-Simons field theory or our Hamiltonian formalism.ootnotetextG. Murthy and R. Shankar, Rev. Mod. Phys., 75, 1101, (2003) We describe a way to introduce CF's by embedding the Chern band in an auxiliary problem involving Landau levels. The embedded band can be designed to approximate a prescribed Chern density in k space which determines the commutation relations of the charge densities and hence preserve all dynamical and algebraic aspects of the original problem. We find some states for which the filling fraction and dimensionless Hall conductance are not equal. The approach extends to two-dimensional time-reversal invariant topological insulators and to composite bosons.

  7. Simulated constant-head boundary for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the constant head-boundary used to simulate ground-water inflow or outflow at the lateral boundary of the Death Valley regional...

  8. Simulated constant-head boundary for the transient ground-water flow model, Death Valley regional ground-water flow system, Nevada and California

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This digital data set represents the constant head-boundary used to simulate ground-water inflow or outflow at the lateral boundary of the Death Valley regional...

  9. A summary of the Planck constant measurements using a watt balance with a superconducting solenoid at NIST

    CERN Document Server

    Schlamminger, S; Haddad, D; Newell, D B; Seifert, F; Chao, L S; Liu, R; Williams, E R; Pratt, J R

    2015-01-01

    Researchers at the National Institute of Standards and Technology have been using a watt balance, NIST-3, to measure the Planck constant $h$ for over ten years. Two recently published values disagree by more than one standard uncertainty. The motivation for the present manuscript is twofold. First, we correct the latest published number to take into account a recently discovered systematic error in mass dissemination at the Bureau International des Poids et Mesures (BIPM). Second, we provide guidance on how to combine the two numbers into one final result. In order to adequately reflect the discrepancy, we added an additional systematic uncertainty to the published uncertainty budgets. The final value of $h$ measured with NIST-3 is $h = 6.626\\,069\\,36(37)\\times 10^{-34}\\,\\mbox{J\\,s}$. This result is $77(57) \\times 10^{-9}$ fractionally higher than $h_{\\mathrm{90}}$. Each number in parentheses gives the value of the standard uncertainty in the last two digits of the respective value and $h_{\\mathrm{90}}$ is th...

  10. Single-User Blind Channel Equalization Using Modified Constant Modulus Algorithm

    Institute of Scientific and Technical Information of China (English)

    孙守宇; 郑君里; 吴里江; 张琪

    2004-01-01

    A modified constant modulus algorithm (MCMA) for blind channel equalization is proposed by modifying the constant modulus error function. The MCMA is compared with the conventional constant modulus algorithm (CMA) for symbol-spaced equalization of 4PSK signals. The result shows that the performance of the MCMA is superior to that of the CMA in both convergence rate and intersymbol interference for frequency selective channels in noisy environments. Simulation results using 8PSK signals also demonstrate that a fractionally spaced equalizer can preserve performance over variations in symbol-timing phase,whereas a baud-rate equalizer cannot.

  11. Mouse skin damages caused by fractionated irradiation with carbon ions

    Energy Technology Data Exchange (ETDEWEB)

    Ando, K.; Chen, Y.J.; Ohira, C.; Nojima, K.; Ando, S.; Kobayashi, N.; Ohbuchi, T.; Shimizu, W. [Space and Particle Radiation Science Research Group, Chiba (Japan); Koike, S.; Kanai, T. [National Inst. of Radiological Sciences, Chiba (Japan). Div. of Accelerator Physics

    1997-09-01

    We have investigated carbon-dose responses of early and late skin damages after daily fractionations to the mouse leg. Depilated legs were irradiated with 7 different positions within 290 MeV/u carbon beams. Fractionation schedules were 1, 2, 4 and 8 daily fractions. Skin reaction was scored every other day for 32 days. Five highest scores in individual mice were averaged, and used as averaged peak reaction. The isoeffect doses to produce an averaged peak skin reaction of 3.0 (moist desquamation) on dose-response curves were calculated with 95% confidence limit. The isoeffect dose for control gamma rays constantly increased with an increase in the number of fraction. The isoeffect doses in low LET carbon ions of 14- and 20 keV/{mu}m also increased up to 4 fractions, but did not increase when 4 fractions increased to 8 fractions. The saturation of isoeffect dose was more prominently observed for 40 keV/{mu}m in such that the isoeffect doses did not change among 2, 4 and 8 fractions. The isoeffect doses for LET higher than 50 keV/{mu}m were smaller than those for lower LET. However, the isoeffect doses for 50-, 60-, 80- and 100 keV/{mu} steadily increased with an increase in the number of fraction and did not show any saturation up to 8 fractions. Relation between LET and RBE was linear for all fractionation schedules. The slope of regression line in 4 fractions was steepest, and significantly (P<0.05) different from that in 1 fraction. (orig.)

  12. Cognitive Hacking and Digital Government: Digital Identity

    OpenAIRE

    Paul Thompson

    2004-01-01

    Recently the National Center for Digital Government held a workshop on "The Virtual Citizen: Identity, Autonomy, and Accountability: A Civic Scenario Exploration of the Role of Identity in On-Line. Discussions at the workshop focused on five scenarios for future authentication policies with respect to digital identity. The underlying technologies considered for authentication were: biometrics: cryptography, with a focus on digital signatures; secure processing/computation; and reputation syst...

  13. Constant Width Planar Computation Characterizes ACC0

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt

    2006-01-01

    We obtain a characterization of ACC0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...

  14. Constant Width Planar Computation Characterizes ACC0

    DEFF Research Database (Denmark)

    Hansen, K.A.

    2004-01-01

    We obtain a characterization of ACC 0 in terms of a natural class of constant width circuits, namely in terms of constant width polynomial size planar circuits. This is shown via a characterization of the class of acyclic digraphs which can be embedded on a cylinder surface in such a way that all...

  15. Chiral Corrections to Vector Meson Decay Constants

    CERN Document Server

    Bijnens, J; Talavera, P; Bijnens, Johan; Gosdzinsky, Peter; Talavera, Pere

    1998-01-01

    We calculate the leading quark mass corrections of order $m_q\\log(m_q)$, $m_q$ and $m_q^{3/2}$ to the vector meson decay constants within Heavy Vector Meson Chiral Perturbation Theory. We discuss the issue of electromagnetic gauge invariance and the heavy mass expansion. Reasonably good fits to the observed decay constants are obtained.

  16. Constant Angle Surfaces in the Heisenberg Group

    Institute of Scientific and Technical Information of China (English)

    Johan FASTENAKELS; Marian Ioan MUNTEANU; Joeri VAN DER VEKEN

    2011-01-01

    In this article we extend the notion of constant angle surfaces in S2 × R and H2 × R to general Bianchi-Cartan-Vranceanu spaces. We show that these surfaces have constant Gaussian curvature and we give a complete local classification in the Heisenberg group.

  17. The time constant of the somatogravic illusion.

    Science.gov (United States)

    Correia Grácio, B J; de Winkel, K N; Groen, E L; Wentink, M; Bos, J E

    2013-02-01

    Without visual feedback, humans perceive tilt when experiencing a sustained linear acceleration. This tilt illusion is commonly referred to as the somatogravic illusion. Although the physiological basis of the illusion seems to be well understood, the dynamic behavior is still subject to discussion. In this study, the dynamic behavior of the illusion was measured experimentally for three motion profiles with different frequency content. Subjects were exposed to pure centripetal accelerations in the lateral direction and were asked to indicate their tilt percept by means of a joystick. Variable-radius centrifugation during constant angular rotation was used to generate these motion profiles. Two self-motion perception models were fitted to the experimental data and were used to obtain the time constant of the somatogravic illusion. Results showed that the time constant of the somatogravic illusion was on the order of two seconds, in contrast to the higher time constant found in fixed-radius centrifugation studies. Furthermore, the time constant was significantly affected by the frequency content of the motion profiles. Motion profiles with higher frequency content revealed shorter time constants which cannot be explained by self-motion perception models that assume a fixed time constant. Therefore, these models need to be improved with a mechanism that deals with this variable time constant. Apart from the fundamental importance, these results also have practical consequences for the simulation of sustained accelerations in motion simulators.

  18. Physical Properties of Triglycerides IV. Dielectric Constant

    NARCIS (Netherlands)

    Gouw, T.H.; Vlugter, J.C.

    1967-01-01

    Dielectric constants at 20° and at 40° C of a number of triglycerides in the liquid state have been measured. A molar additive function of the dielectric constant, based on a relation derived by J. van Elk, was used in combination with a previously derived equation for triglycerides to give an equat

  19. Decay constants from twisted mass QCD

    CERN Document Server

    Dimopoulos, P; Michael, C; Simula, S; Urbach, C

    2008-01-01

    We present results for chiral extrapolations of the mass and decay constants of the rho meson. The data sets used are the nf=2 unquenched gauge configurations generated with twisted mass fermions by the European Twisted Mass Collaboration. We describe a calculation of three decay constants in charmonium and explain why they are required.

  20. Digital Archive Policies and Trusted Digital Repositories

    Directory of Open Access Journals (Sweden)

    MacKenzie Smith

    2007-07-01

    Full Text Available The MIT Libraries, the San Diego Supercomputer Center, and the University of California San Diego Libraries are conducting the PLEDGE Project to determine the set of policies that affect operational digital preservation archives and to develop standardized means of recording and enforcing them using rules engines. This has the potential to allow for automated assessment of “trustworthiness” of digital preservation archives. We are also evaluating the completeness of other efforts to define policies for digital preservation such as the RLG/NARA Trusted Digital Repository checklist and the PREMIS metadata schema. We present our results to date.

  1. Asymptotic behavior of solutions of forced fractional differential equations

    Directory of Open Access Journals (Sweden)

    Said Grace

    2016-09-01

    where $y(t=\\left( a(tx^{\\prime }(t\\right ^{\\prime }$, $c_{0}=\\frac{y(c}{\\Gamma (1}=y(c$, and $c_{0}$ is a real constant. The technique used in obtaining their results will apply to related fractional differential equations with Caputo derivatives of any order. Examples illustrate the results obtained in this paper.

  2. String theory, cosmology and varying constants

    Science.gov (United States)

    Damour, Thibault

    In string theory the coupling `constants' appearing in the low-energy effective Lagrangian are determined by the vacuum expectation values of some (a priori) massless scalar fields (dilaton, moduli). This naturally leads one to expect a correlated variation of all the coupling constants, and an associated violation of the equivalence principle. We review some string-inspired theoretical models which incorporate such a spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring a very unnatural fine-tuning of parameters, a variation of the fine-structure constant as large as that recently `observed' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universality of free fall, such as MICROSCOPE and STEP.

  3. String theory, cosmology and varying constants

    CERN Document Server

    Damour, Thibault Marie Alban Guillaume

    2002-01-01

    In string theory the coupling ``constants'' appearing in the low-energy effective Lagrangian are determined by the vacuum expectation values of some (a priori) massless scalar fields (dilaton, moduli). This naturally leads one to expect a correlated variation of all the coupling constants, and an associated violation of the equivalence principle. We review some string-inspired theoretical models which incorporate such a spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring a very unnatural fine-tuning of parameters, a variation of the fine-structure constant as large as that recently ``observed'' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universa...

  4. Cosmic Time Variation of the Gravitational Constant

    CERN Document Server

    Tomaschitz, R

    2000-01-01

    A pre-relativistic cosmological approach to electromagnetism and gravitation is explored that leads to a cosmic time variation of the fundamental constants. Space itself is supposed to have physical substance, which manifests by its permeability. The scale factors of the permeability tensor induce a time variation of the fundamental constants. Atomic radii, periods, and energy levels scale in cosmic time, which results in dispersionless redshifts without invoking a space expansion. Hubble constant and deceleration parameter are reviewed in this context. The time variation of the gravitational constant at the present epoch can be expressed in terms of these quantities. This provides a completely new way to restrain the deceleration parameter from laboratory bounds on the time variation of the gravitational constant. This variation also affects the redshift dependence of angular diameters and the surface brightness, and we study in some detail the redshift scaling of the linear sizes of radio sources. The effec...

  5. General Relativity, Cosmological Constant and Modular Forms

    CERN Document Server

    Kraniotis, G V

    2001-01-01

    Strong field (exact) solutions of the gravitational field equations of General Relativity in the presence of a Cosmological Constant are investigated. In particular, a full exact solution is derived within the inhomogeneous Szekeres-Szafron family of space-time line element with a nonzero Cosmological Constant. The resulting solution connects, in an intrinsic way, General Relativity with the theory of modular forms and elliptic curves and thus to the theory of Taniyama-Shimura.The homogeneous FLRW limit of the above space-time elements is recovered and we solve exactly the resulting Friedmann Robertson field equation with the appropriate matter density for generic values of the Cosmological Constant $ \\Lambda $ and curvature constant $K$. A formal expression for the Hubble constant is derived. The cosmological implications of the resulting non-linear solutions are systematically investigated. Two particularly interesting solutions i) the case of a flat universe $K=0,\\Lambda \

  6. Gauge Invariant Fractional Electromagnetic Fields

    CERN Document Server

    Lazo, Matheus Jatkoske

    2011-01-01

    Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators.

  7. A picosecond resolution Time Digitizer for laser ranging

    Science.gov (United States)

    Turko, B.

    1978-01-01

    The Time Digitizer capable of covering a range of 0.34 sec in 9.76 psec increments is described. The time interval between a pair of start-stop pulses is digitized coarsely in 20 nsec periods by a very accurate 50 MHz reference clock. The residual fractions of a clock period at the start and the stop end of the measured interval are stretched in two interpolators and digitized in 9.76 psec increments. An equivalent digitizing frequency of 102.4 GHz is thus achieved. The digitizer is built in a minicrate and communicates via a standard crate controller. It is intended for use in the laser ranging between ground stations and the Laser Geodetic Satellite (LAGEOS). It is shown that the distribution in any two adjacent 9.76 psec channels of a small number of identical test time intervals is essentially binomial. The performance of the digitizer and test results are given.

  8. Fractional Langevin equation and Riemann-Liouville fractional derivative.

    Science.gov (United States)

    Sau Fa, Kwok

    2007-10-01

    In this present work we consider a fractional Langevin equation with Riemann-Liouville fractional time derivative which modifies the classical Newtonian force, nonlocal dissipative force, and long-time correlation. We investigate the first two moments, variances and position and velocity correlation functions of this system. We also compare them with the results obtained from the same fractional Langevin equation which uses the Caputo fractional derivative.

  9. Logic of the digital

    CERN Document Server

    Evens, Aden

    2015-01-01

    Building a foundational understanding of the digital, Logic of the Digital reveals a unique digital ontology. Beginning from formal and technical characteristics, especially the binary code at the core of all digital technologies, Aden Evens traces the pathways along which the digital domain of abstract logic encounters the material, human world. How does a code using only 0s and 1s give rise to the vast range of applications and information that constitutes a great and growing portion of our world? Evens' analysis shows how any encounter between the actual and the digital must cross an ontolo

  10. Preheating with fractional powers

    Science.gov (United States)

    Moghaddam, Hossein Bazrafshan; Brandenberger, Robert

    2016-11-01

    We consider preheating in models in which the potential for the inflaton is given by a fractional power, as is the case in axion monodromy inflation. We assume a standard coupling between the inflaton field and a scalar matter field. We find that in spite of the fact that the oscillation of the inflaton about the field value which minimizes the potential is anharmonic, there is nevertheless a parametric resonance instability, and we determine the Floquet exponent which describes this instability as a function of the parameters of the inflaton potential.

  11. Fractional cointegration rank estimation

    DEFF Research Database (Denmark)

    Lasak, Katarzyna; Velasco, Carlos

    We consider cointegration rank estimation for a p-dimensional Fractional Vector Error Correction Model. We propose a new two-step procedure which allows testing for further long-run equilibrium relations with possibly different persistence levels. The fi…rst step consists in estimating......-likelihood ratio test of no-cointegration on the estimated p - r common trends that are not cointegrated under the null. The cointegration degree is re-estimated in the second step to allow for new cointegration relationships with different memory. We augment the error correction model in the second step...

  12. Fractional Reserve Banking

    OpenAIRE

    Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas

    2012-01-01

    Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...

  13. Fractional Reserve Banking

    OpenAIRE

    Andreasen, Niels; Bjerregaard, Mads; Lund, Jonas; Olsen, Ove Bitsch; Rasmussen, Andreas Dalgas

    2012-01-01

    Projektet er bygget op omkring kritisk realisme, som er det gennemgående videnskabelige fundament til undersøgelsen af hvilke strukturelle grunde der er til finansiel ustabilitet i Danmark. Projektet går i dybden med Fractional Reserve Banking og incitamentsstrukturen i banksystemet. Vi bevæger os både på det makro- og mikroøkonomiske niveau i analysen. På makro niveau bruger vi den østrigske skole om konjunktur teori (The Positive Theory of the Cycle). På mikro niveau arbejder vi med princip...

  14. The effect of aqueous organic solvents on the dissociation constants and thermodynamic properties of alkanolamines

    NARCIS (Netherlands)

    Hamborg, Espen S.; van Aken, Coen; Versteeg, Geert F.

    2010-01-01

    The dissociation constants of protonated monoethanolamine and N-methyldiethanolamine have been determined in methanol-water, ethanol-water, and t-butanol-water solvents. The alcohol mole fractions were ranging from 0.2 to 0.95 and the temperatures from 283 to 323 K, 283 to 333 K, and at 298.15 K, re

  15. A Measurement Of The Strong Coupling Constant From Jet Analysis At Babar

    CERN Document Server

    Ford, K E

    2001-01-01

    I measure the two-, three- and four-jet fractions in the four flavour continuum near s≈10.5 GeV. From this, I extracted a value for the strong coupling constant (αs) of αs(10.53GeV) = 0.1319 ± 0.0848 ± 0.0100.

  16. Fractional Integral Inequalities via Hadamard’s Fractional Integral

    OpenAIRE

    2014-01-01

    We establish new fractional integral inequalities, via Hadamard’s fractional integral. Several new integral inequalities are obtained, including a Grüss type Hadamard fractional integral inequality, by using Young and weighted AM-GM inequalities. Many special cases are also discussed.

  17. Body Fractions: A Physical Approach to Fraction Learning

    Science.gov (United States)

    Mills, Judith

    2011-01-01

    Many students experience great difficulty understanding the meaning of fractions. For many students who have spent their early mathematics lessons focusing on counting (whole) numbers, recognising that there are many numbers between those whole numbers called fractional numbers, is quite revolutionary. The foundation of understanding fractions is…

  18. Cosmological Models with Fractional Derivatives and Fractional Action Functional

    Institute of Scientific and Technical Information of China (English)

    V.K. Shchigolev

    2011-01-01

    Cosmological models of a scalar field with dynamical equations containing fractional derivatives or derived from the Einstein-Hilbert action of fractional order, are constructed. A number of exact solutions to those equations of fractional cosmological models in both eases is given.

  19. Study of time resolution by digital methods with a DRS4 module

    Science.gov (United States)

    Du, Cheng-Ming, Du; Jin-Da, Chen; Xiu-Ling, Zhang; Yang, Hai-Bo; Cheng, Ke; Kong, Jie; Hu, Zheng-Guo; Sun, Zhi-Yu; Su, Hong; Xu, Hu-Shan

    2016-04-01

    A new Digital Pulse Processing (DPP) module has been developed, based on a domino ring sampler version 4 chip (DRS4), with good time resolution for LaBr3 detectors, and different digital timing analysis methods for processing the raw detector signals are reported. The module, composed of an eight channel DRS4 chip, was used as the readout electronics and acquisition system to process the output signals from XP20D0 photomultiplier tubes (PMTs). Two PMTs were coupled with LaBr3 scintillators and placed on opposite sides of a radioactive positron 22Na source for 511 keV γ-ray tests. By analyzing the raw data acquired by the module, the best coincidence timing resolution is about 194.7 ps (FWHM), obtained by the digital constant fraction discrimination (dCFD) method, which is better than other digital methods and analysis methods based on conventional analog systems which have been tested. The results indicate that it is a promising approach to better localize the positron annihilation in positron emission tomography (PET) with time of flight (TOF), as well as for scintillation timing measurement, such as in TOF-ΔE and TOF-E systems for particle identification, with picosecond accuracy timing measurement. Furthermore, this module is more simple and convenient than other systems. Supported by the Science Foundation of the Chinese Academy of Sciences (210340XBO), National Natural Science Foundation of China (11305233,11205222), General Program of National Natural Science Foundation of China (11475234), Specific Fund of National Key Scientific Instrument and Equipment Development Project (2011YQ12009604) and Joint Fund for Research Based on Large-Scale Scientific Facilities (U1532131).

  20. The Geminga Fraction

    CERN Document Server

    Harding, A K; Gonthier, P L; Harding, Alice K.; Grenier, Isabelle A.; Gonthier, Peter L.

    2007-01-01

    Radio-quiet gamma-ray pulsars like Geminga may account for a number of the unidentified EGRET sources in the Galaxy. The number of Geminga-like pulsars is very sensitive to the geometry of both the gamma-ray and radio beams. Recent studies of the shape and polarization of pulse profiles of young radio pulsars have provided evidence that their radio emission originates in wide cone beams at altitudes that are a significant fraction (1 -10%) of their light cylinder radius. Such wide radio emission beams will be visible at a much larger range of observer angles than the narrow core components thought to originate at lower altitude. Using 3D geometrical modeling that includes relativistic effects from pulsar rotation, we study the visibility of such radio cone beams as well as that of the gamma-ray beams predicted by slot gap and outer gap models. From the results of this study one can obtain revised predictions for the fraction of Geminga-like, radio quiet pulsars present in the gamma-ray pulsar population.

  1. NESDIS VIIRS Green Vegetation Fraction

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains weekly Green Vegetation Fraction (GVF) derived from VIIRS. The Green Vegetation Fraction product is updated daily and is used as an input to...

  2. Advances in robust fractional control

    CERN Document Server

    Padula, Fabrizio

    2015-01-01

    This monograph presents design methodologies for (robust) fractional control systems. It shows the reader how to take advantage of the superior flexibility of fractional control systems compared with integer-order systems in achieving more challenging control requirements. There is a high degree of current interest in fractional systems and fractional control arising from both academia and industry and readers from both milieux are catered to in the text. Different design approaches having in common a trade-off between robustness and performance of the control system are considered explicitly. The text generalizes methodologies, techniques and theoretical results that have been successfully applied in classical (integer) control to the fractional case. The first part of Advances in Robust Fractional Control is the more industrially-oriented. It focuses on the design of fractional controllers for integer processes. In particular, it considers fractional-order proportional-integral-derivative controllers, becau...

  3. Some Zero-Sum Constants with Weights

    Indian Academy of Sciences (India)

    S D Adhikari; R Balasubramanian; F Pappalardi; P Rath

    2008-05-01

    For an abelian group , the Davenport constant () is defined to be the smallest natural number such that any sequence of elements in has a non-empty subsequence whose sum is zero (the identity element). Motivated by some recent developments around the notion of Davenport constant with weights, we study them in some basic cases. We also define a new combinatorial invariant related to $(\\mathbb{Z}/n\\mathbb{Z})^d$, more in the spirit of some constants considered by Harborth and others and obtain its exact value in the case of $(\\mathbb{Z}/n\\mathbb{Z})^2$ where is an odd integer.

  4. EFFECTS OF CONSTANT EXCITATION ON LOCAL BIFURCATION

    Institute of Scientific and Technical Information of China (English)

    WU Zhi-qiang; CHEN Yu-shu

    2006-01-01

    The effects of the constant excitation on the local bifurcation of the periodic solutions in the 1:2 internal resonant systems were analyzed based on the singularity theory. It is shown that the constant excitation make influence only when there exist some nonlinear terms, in the oscillator with lower frequency. Besides acting as main bifurcation parameter, the constant excitation, together with coefficients of some nonlinear terms,may change the values of unfolding parameters and the type of the bifurcation. Under the non-degenerate cases, the effect of the third order terms can be neglected.

  5. The Determination of the Strong Coupling Constant

    Science.gov (United States)

    Dissertori, Günther

    2016-10-01

    The strong coupling constant is one of the fundamental parameters of the Standard Theory of particle physics. In this review I will briefly summarise the theoretical framework, within which the strong coupling constant is defined and how it is connected to measurable observables. Then I will give an historical overview of its experimental determinations and discuss the current status and world average value. Among the many different techniques used to determine this coupling constant in the context of quantum chromodynamics, I will focus in particular on a number of measurements carried out at the Large Electron-Positron Collider (LEP) and the Large Hadron Collider (LHC) at CERN.

  6. On the digital homology groups of digital images

    CERN Document Server

    Lee, Dae-Woong

    2011-01-01

    In this article we study the digital homology groups of digital images which are based on the singular homology groups of topological spaces in algebraic topology. Specifically, we define a digitally standard $n$-simplex, a digitally singular $n$-simplex, and the digital homology groups of digital images with $k$-adjacency relations. We then construct a covariant functor from a category of digital images and digitally continuous functions to the one of abelian groups and group homomorphisms, and investigate some fundamental and interesting properties of digital homology groups of digital images, such as the digital version of the dimension axiom which is one of the Eilenberg-Steenrod axioms.

  7. Fractional Reserve in Banking System

    OpenAIRE

    Valkonen, Maria

    2016-01-01

    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...

  8. Fractional Reserve in Banking System

    OpenAIRE

    Valkonen, Maria

    2016-01-01

    This thesis is aimed to provide understanding of the role of the fractional reserve in the mod-ern banking system worldwide and particularly in Finland. The fractional reserve banking is used worldwide, but the benefits of this system are very disputable. On the one hand, experts say that the fractional reserve is a necessary instrument for the normal business and profit making. On the other hand, sceptics openly criticize the fractional reserve system and blame it for fiat money (money n...

  9. Experimental observation of fractional echoes

    Science.gov (United States)

    Karras, G.; Hertz, E.; Billard, F.; Lavorel, B.; Siour, G.; Hartmann, J.-M.; Faucher, O.; Gershnabel, Erez; Prior, Yehiam; Averbukh, Ilya Sh.

    2016-09-01

    We report the observation of fractional echoes in a double-pulse excited nonlinear system. Unlike standard echoes, which appear periodically at delays which are integer multiples of the delay between the two exciting pulses, the fractional echoes appear at rational fractions of this delay. We discuss the mechanism leading to this phenomenon, and provide experimental demonstration of fractional echoes by measuring third harmonic generation in a thermal gas of CO2 molecules excited by a pair of femtosecond laser pulses.

  10. Digital rectal exam

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007069.htm Digital rectal exam To use the sharing features on this page, please enable JavaScript. A digital rectal exam is an examination of the lower ...

  11. Identidad visual digital

    OpenAIRE

    Pérez Villanueva, Alba

    2013-01-01

    Se estudian seis casos de empresas de diferentes sectores y la adaptación de la identidad visual digital para obtener una imagen aproximada sobre el estado de la identidad visual digital de las coporaciones

  12. Coastal California Digital Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This digital ortho-imagery dataset is a survey of coastal California. The project area consists of approximately 3774 square miles. The project design of the digital...

  13. About group digital signatures

    National Research Council Canada - National Science Library

    Adriana Cristina Enache

    2012-01-01

    ...).A group digital signature is a digital signature with enhanced privacy features that allows members of a given group to anonymously sign messages on behalf of the group, producing a group signature...

  14. Marshak waves: Constant flux vs constant T-a (slight) paradigm shift

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, M.D.

    1994-12-22

    We review the basic scaling laws for Marshak waves and point out the differences in results for wall loss, albedo, and Marshak depth when a constant absorbed flux is considered as opposed to a constant absorbed temperature. Comparisons with LASNEX simulations and with data are presented that imply that a constant absorbed flux is a more appropriate boundary condition.

  15. Fractional Hopfield Neural Networks: Fractional Dynamic Associative Recurrent Neural Networks.

    Science.gov (United States)

    Pu, Yi-Fei; Yi, Zhang; Zhou, Ji-Liu

    2016-07-14

    This paper mainly discusses a novel conceptual framework: fractional Hopfield neural networks (FHNN). As is commonly known, fractional calculus has been incorporated into artificial neural networks, mainly because of its long-term memory and nonlocality. Some researchers have made interesting attempts at fractional neural networks and gained competitive advantages over integer-order neural networks. Therefore, it is naturally makes one ponder how to generalize the first-order Hopfield neural networks to the fractional-order ones, and how to implement FHNN by means of fractional calculus. We propose to introduce a novel mathematical method: fractional calculus to implement FHNN. First, we implement fractor in the form of an analog circuit. Second, we implement FHNN by utilizing fractor and the fractional steepest descent approach, construct its Lyapunov function, and further analyze its attractors. Third, we perform experiments to analyze the stability and convergence of FHNN, and further discuss its applications to the defense against chip cloning attacks for anticounterfeiting. The main contribution of our work is to propose FHNN in the form of an analog circuit by utilizing a fractor and the fractional steepest descent approach, construct its Lyapunov function, prove its Lyapunov stability, analyze its attractors, and apply FHNN to the defense against chip cloning attacks for anticounterfeiting. A significant advantage of FHNN is that its attractors essentially relate to the neuron's fractional order. FHNN possesses the fractional-order-stability and fractional-order-sensitivity characteristics.

  16. Efficacy and safety of Erbium-doped Yttrium Aluminium Garnet fractional resurfacing laser for treatment of facial acne scars

    Directory of Open Access Journals (Sweden)

    Balakrishnan Nirmal

    2013-01-01

    Full Text Available Background: Treatment of acne scars with ablative fractional laser resurfacing has given good improvement. But, data on Indian skin are limited. A study comparing qualitative, quantitative, and subjective assessments is also lacking. Aim: Our aim was to assess the improvement of facial acne scars with Erbium-doped Yttrium Aluminium Garnet (Er:YAG 2940 nm fractional laser resurfacing and its adverse effects in 25 patients at a tertiary care teaching hospital. Methods: All 25 patients received four treatment sessions with Er:YAG fractional laser at 1-month interval. The laser parameters were kept constant for each of the four sittings in all patients. Qualitative and quantitative assessments were done using Goodman and Barron grading. Subjective assessment in percentage of improvement was also documented 1 month after each session. Photographs were taken before each treatment session and 1 month after the final session. Two unbiased dermatologists performed independent clinical assessments by comparing the photographs. The kappa statistics was used to monitor the agreement between the dermatologists and patients. Results: Most patients (96% showed atleast fair improvement. Rolling and superficial box scars showed higher significant improvement when compared with ice pick and deep box scars. Patient′s satisfaction of improvement was higher when compared to physician′s observations. No serious adverse effects were noted with exacerbation of acne lesions forming the majority. Conclusion: Ablative fractional photothermolysis is both effective and safe treatment for atrophic acne scars in Indian skin.Precise evaluation of acne scar treatment can be done by taking consistent digital photographs.

  17. Nonholonomic constraints with fractional derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Tarasov, Vasily E [Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow 119992 (Russian Federation); Zaslavsky, George M [Courant Institute of Mathematical Sciences, New York University, 251 Mercer St, New York, NY 10012 (United States)

    2006-08-04

    We consider the fractional generalization of nonholonomic constraints defined by equations with fractional derivatives and provide some examples. The corresponding equations of motion are derived using variational principle. We prove that fractional constraints can be used to describe the evolution of dynamical systems in which some coordinates and velocities are related to velocities through a power-law memory function.

  18. Digital Inkjet Textile Printing

    OpenAIRE

    Wang, Meichun

    2017-01-01

    Digital inkjet textile printing is an emerging technology developed with the rise of the digital world. It offers a possibility to print high-resolution images with unlimited color selection on fabrics. Digital inkjet printing brings a revolutionary chance for the textile printing industry. The history of textile printing shows the law how new technology replaces the traditional way of printing. This indicates the future of digital inkjet textile printing is relatively positive. Differen...

  19. Basic digital signal processing

    CERN Document Server

    Lockhart, Gordon B

    1985-01-01

    Basic Digital Signal Processing describes the principles of digital signal processing and experiments with BASIC programs involving the fast Fourier theorem (FFT). The book reviews the fundamentals of the BASIC program, continuous and discrete time signals including analog signals, Fourier analysis, discrete Fourier transform, signal energy, power. The text also explains digital signal processing involving digital filters, linear time-variant systems, discrete time unit impulse, discrete-time convolution, and the alternative structure for second order infinite impulse response (IIR) sections.

  20. Digital dannelse til gymnasieeleverne

    DEFF Research Database (Denmark)

    Kaarsted, Thomas; Holch Andersen, Knud

    2012-01-01

    Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene.......Søsætningen af en ny tænketank skal udstikke nye digital retningslinjer for gymnasiekolerne. Baggrunden er en erkendelse af, at it-infrastruktur og digital teknologi ikke gør de alene....

  1. Digital flight control research

    Science.gov (United States)

    Potter, J. E.; Stern, R. G.; Smith, T. B.; Sinha, P.

    1974-01-01

    The results of studies which were undertaken to contribute to the design of digital flight control systems, particularly for transport aircraft are presented. In addition to the overall design considerations for a digital flight control system, the following topics are discussed in detail: (1) aircraft attitude reference system design, (2) the digital computer configuration, (3) the design of a typical digital autopilot for transport aircraft, and (4) a hybrid flight simulator.

  2. Online Digital Trading

    Directory of Open Access Journals (Sweden)

    Felician Alecu

    2013-09-01

    Full Text Available This paper summarizes the main options a digital content creator has in order to obtain money by online trading of digital works. There are multiple ways to get paid for the digital products, like licensing, for example, however this article tries to present the most successful business models targeting the online market. The exclusive rights stated by the copyright laws are helping the authors to maximize to potential advantages coming from their digital creations.

  3. The Ambivalent Ontology of Digital Artifacts

    DEFF Research Database (Denmark)

    Kallinikos, Jannis; Aaltonen, Aleksi; Marton, Attila

    2013-01-01

    Digital artifacts are embedded in wider and constantly shifting ecosystems such that they become increasingly editable, interactive, reprogrammable, and distributable. This state of flux and constant transfiguration renders the value and utility of these artifacts contingent on shifting webs...... of functional relations with other artifacts across specific contexts and organizations. By the same token, it apportions control over the development and use of these artifacts over a range of dispersed stakeholders and makes their management a complex technical and social undertaking. These ideas...... are illustrated with reference to (1) provenance and authenticity of digital documents within the overall context of archiving and social memory and (2) the content dynamics occasioned by the findability of content mediated by Internet search engines. We conclude that the steady change and transfiguration...

  4. The time constant of the somatogravic illusion

    NARCIS (Netherlands)

    Correia Grácio, B.J.; Winkel, K.N. de; Groen, E.L.; Wentink, M.; Bos, J.E.

    2013-01-01

    Met desdemona hebben we gevonden dat de tijd constante van de somatografische illusie rond twee seconden is. Dit resultaat verschilt van wat was gevonden in ander onderzoek dat gebruikt maakt van een gewone centrifuge

  5. Black holes with constant topological Euler density

    CERN Document Server

    Bargueño, Pedro

    2016-01-01

    A class of four dimensional spherically symmetric and static geometries with constant topological Euler density is studied. These geometries are shown to solve the coupled Einstein-Maxwell system when non-linear Born-Infeld-like electrodynamics is employed.

  6. STABILITY CONSTANT OF THE TRISGLYCINATO METAL ...

    African Journals Online (AJOL)

    DR. AMINU

    Department of Pure and Industrial Chemistry,Bayero University Kano, P. M. B. 3011, Kano, ... The stability constants of iron, manganese, cobalt, and nickel complexes of glycine have been ... bidentate ligand in its coordination with metal ions.

  7. Interacting universes and the cosmological constant

    Energy Technology Data Exchange (ETDEWEB)

    Alonso-Serrano, A. [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Bastos, C. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Departamento de Física e Astronomia, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Robles-Pérez, S., E-mail: salvarp@imaff.cfmac.csic.es [Centro de Física “Miguel Catalán”, Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas, Serrano 121, 28006 Madrid (Spain); Estación Ecológica de Biocosmología, Pedro de Alvarado 14, 06411 Medellín (Spain); Física Teórica, Universidad del País Vasco, Apartado 644, 48080 Bilbao (Spain)

    2013-02-12

    In this Letter it is studied the effects that an interaction scheme among universes can have in the values of their cosmological constants. In the case of two interacting universes, the value of the cosmological constant of one of the universes becomes very close to zero at the expense of an increasing value of the cosmological constant of the partner universe. In the more general case of a chain of N interacting universes with periodic boundary conditions, the spectrum of the Hamiltonian splits into a large number of levels, each of them associated with a particular value of the cosmological constant, that can be occupied by single universes revealing a collective behavior that plainly shows that the multiverse is much more than the mere sum of its parts.

  8. Determination of the gravitational constant G

    Institute of Scientific and Technical Information of China (English)

    HU Zhong-kun; LIU Qi; LUO Jun

    2006-01-01

    A precise knowledge of the Newtonian gravitational constant G has an important role in physics and is of considerable meteorological interest.Although G was the first physical constant to be introduced and measured in the history of science,it is still the least precisely determined of all the fundamental constants of nature.The 2002 CODATA recommended value for G,G=(6.6742±0.0010)×10-11m3·kg-1·s-2,has an uncertainty of 150 parts per million (ppm),much larger than that of all other fundamental constants.Reviewed here is the status of our knowledge of the absolute value of G,methods for determining G,and recent high precision experiments for determining G.

  9. Interactive Digital Signal Processor

    Science.gov (United States)

    Mish, W. H.

    1985-01-01

    Interactive Digital Signal Processor, IDSP, consists of set of time series analysis "operators" based on various algorithms commonly used for digital signal analysis. Processing of digital signal time series to extract information usually achieved by applications of number of fairly standard operations. IDSP excellent teaching tool for demonstrating application for time series operators to artificially generated signals.

  10. Digital Literacy. Research Brief

    Science.gov (United States)

    Williamson, Ronald

    2011-01-01

    21st Century students need a complex set of skills to be successful in a digital environment. Digital literacy, similar to traditional definitions of literacy, is a set of skills students use to locate, organize, understand, evaluate and create information. The difference is that it occurs in an environment where a growing set of digital tools…

  11. Personal Digital Video Stories

    DEFF Research Database (Denmark)

    Ørngreen, Rikke; Henningsen, Birgitte Sølbeck; Louw, Arnt Vestergaard

    2016-01-01

    agenda focusing on video productions in combination with digital storytelling, followed by a presentation of the digital storytelling features. The paper concludes with a suggestion to initiate research in what is identified as Personal Digital Video (PDV) Stories within longitudinal settings, while...

  12. Digital language death.

    Directory of Open Access Journals (Sweden)

    András Kornai

    Full Text Available Of the approximately 7,000 languages spoken today, some 2,500 are generally considered endangered. Here we argue that this consensus figure vastly underestimates the danger of digital language death, in that less than 5% of all languages can still ascend to the digital realm. We present evidence of a massive die-off caused by the digital divide.

  13. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  14. Digitization in Maritime Industry

    DEFF Research Database (Denmark)

    Constantiou, Ioanna; Shollo, Arisa; Kreiner, Kristian

    2017-01-01

    Digitization in the maritime industry is expected to transform businesses. The recently introduced mobile technologies in inter-organizational processes is an example of digitization in an industry which moves very slowly towards digital transformation. We focus on the influence of mobile...

  15. Behandlingseffekt af Digital Dermatitis

    DEFF Research Database (Denmark)

    Krogh, Kenneth; Thomsen, Peter

    2008-01-01

    af klovlidelser herunder især Digital Dermatitis. Klovregistreringerne viser, at der er stor dynamik og mange nyinfektioner af Digital Dermatitis svarende til problematikken ved mastitis. Behandlingseffekten ved Digital Dermatitis er høj (omkring 90 %) ved den udførte behandling. Behandlingen bestod...

  16. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  17. Reconceptualising Critical Digital Literacy

    Science.gov (United States)

    Pangrazio, Luciana

    2016-01-01

    While it has proved a useful concept during the past 20 years, the notion of "critical digital literacy" requires rethinking in light of the fast-changing nature of young people's digital practices. This paper contrasts long-established notions of "critical digital literacy" (based primarily around the critical consumption of…

  18. Preparing collections for digitization

    CERN Document Server

    Bulow, Anna E

    2010-01-01

    Most libraries, archives and museums are confronting the challenges of providing digital access to their collections. This guide offers guidance covering the end-to-end process of digitizing collections, from selecting records for digitization to choosing suppliers and equipment and dealing with documents that present individual problems.

  19. Digital subtraction laryngography

    Energy Technology Data Exchange (ETDEWEB)

    Brown, B.W.; Enzmann, D.R.; Hopp, M.L.; Castellino, R.A.

    1983-06-01

    Digital subtraction laryngography was used to evaluate laryngeal function in 8 patients: 4 with normal larynxes and 4 with laryngeal disease. Subtracted digital images provided a dynamic display of the extent and symmetry of vocal cord excursions and pyriform sinus inflation, and the vocal cord resting position was also clearly depicted. The technical details of digital subtraction laryngography and its application are described.

  20. Digital Tectonic Tools

    DEFF Research Database (Denmark)

    Schmidt, Anne Marie Due

    2005-01-01

    in particular. A model of the aspects in the term tectonics – epresentation, ontology and culture – will be presented and used to discuss the current digital tools’ ability in tectonics. Furthermore it will be discussed what a digital tectonic tool is and could be and how a connection between the digital...

  1. Prime rings with PI rings of constants

    CERN Document Server

    Kharchenko, V K; Rodríguez-Romo, S

    1996-01-01

    It is shown that if the ring of constants of a restricted differential Lie algebra with a quasi-Frobenius inner part satisfies a polynomial identity (PI) then the original prime ring has a generalized polynomial identitiy (GPI). If additionally the ring of constants is semiprime then the original ring is PI. The case of a non-quasi-Frobenius inner part is also considered.

  2. Trialogue on the number of fundamental constants

    CERN Document Server

    Duff, Michael J; Veneziano, Gabriele

    2002-01-01

    This paper consists of three separate articles on the number of fundamental dimensionful constants in physics. We started our debate in summer 1992 on the terrace of the famous CERN cafeteria. In the summer of 2001 we returned to the subject to find that our views still diverged and decided to explain our current positions. LBO develops the traditional approach with three constants, GV argues in favor of just two, while MJD advocates zero.

  3. The Origin of the Constant Carbohydrate Diet

    Directory of Open Access Journals (Sweden)

    Charles Herbert Read

    2009-01-01

    Full Text Available The Constant Carbohydrate diet, based entirely on carbohydrate exchanges, is now widely used in the dietary treatment of diabetes mellitus. Being based on sound scientific principles and simple in design, the Constant Carabohydrate diet is appropriate for all those having diabetes mellitus, young or old, no matter their ethncity. This report describes why and how it was developed in 1951. Its simplicity makes it adaptable to all ethnic diets.

  4. The Origin of the Constant Carbohydrate Diet

    Directory of Open Access Journals (Sweden)

    Read CharlesHerbert

    2008-01-01

    Full Text Available The Constant Carbohydrate diet, based entirely on carbohydrate exchanges, is now widely used in the dietary treatment of diabetes mellitus. Being based on sound scientific principles and simple in design, the Constant Carabohydrate diet is appropriate for all those having diabetes mellitus, young or old, no matter their ethncity. This report describes why and how it was developed in 1951. Its simplicity makes it adaptable to all ethnic diets.

  5. Compact phase space, cosmological constant, discrete time

    CERN Document Server

    Rovelli, Carlo

    2015-01-01

    We study the quantization of geometry in the presence of a cosmological constant, using a discretiza- tion with constant-curvature simplices. Phase space turns out to be compact and the Hilbert space finite dimensional for each link. Not only the intrinsic, but also the extrinsic geometry turns out to be discrete, pointing to discreetness of time, in addition to space. We work in 2+1 dimensions, but these results may be relevant also for the physical 3+1 case.

  6. Inflationary Phase with Time Varying Fundamental Constants

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2002-01-01

    Following Barrow, and Barrow and collaborators, we find a cosmological JBD model, with varying speed of light and varying fine structure constant, where the deceleration parameter is -1,causing acceleration of the Universe.Indeed, we have an exponential inflationary phase. Plancks time, energy, length,etc.,might have had different numerical values in the past, than those available in the litterature, due to the varying values for speed of light, and gravitational constant.

  7. Beyond lensing by the cosmological constant

    CERN Document Server

    Faraoni, Valerio

    2016-01-01

    The long-standing problem of whether the cosmological constant affects directly the deflection of light caused by a gravitational lens is reconsidered. We use a new approach based on the Hawking quasilocal mass of a sphere grazed by light rays and on its splitting into local and cosmological parts. Previous literature restricted to the cosmological constant is extended to any form of dark energy accelerating the universe in which the gravitational lens is embedded.

  8. Beyond lensing by the cosmological constant

    Science.gov (United States)

    Faraoni, Valerio; Lapierre-Léonard, Marianne

    2017-01-01

    The long-standing problem of whether the cosmological constant affects directly the deflection of light caused by a gravitational lens is reconsidered. We use a new approach based on the Hawking quasilocal mass of a sphere grazed by light rays and on its splitting into local and cosmological parts. Previous literature restricted to the cosmological constant is extended to any form of dark energy accelerating the universe in which the gravitational lens is embedded.

  9. A constant elasticity of profit production function

    OpenAIRE

    Beard, Rodney

    2007-01-01

    Impact analysis of changes in production inputs may be simplified if one can apply a constant adjustment factor to profit. In particular, if a production function can be found for which the elasticity of profit is constant and this function has desirable properties, then one can use the input elasticity of profit to study the impact of input changes on profit. In this paper such a production function is derived from first principles.

  10. Implementing digital preservation in repositories: Knowledge and practices

    Directory of Open Access Journals (Sweden)

    Caterina Groposo Pavão

    2016-09-01

    Full Text Available Digital preservation has to be undertaken by institutional repositories, which are responsible for the preservation of the scientific output from academic institutions. However, due to the constant evolution of the field, to gain domain knowledge and recognise best practices is a complex task for people responsible for digital preservation in those institutions. Digital preservation research, practices and solutions address specific problems, such as formats, curation, reference models, authenticity, policies and preservation plans, tools, etc., while stakeholders need an integrated, contextualized and applicable overview. This paper focuses on the implementation of digital preservation in repositories, from the perspective of the team responsible for the project, regarding the necessary knowledge and best practices. Initially, it defines and contextualizes digital preservation repositories. The following section presents a conceptual model of digital preservation, synthesized from conceptual models developed in influential projects in the field, which allows us to identify the domain knowledge in digital preservation. Finally, aspects represented in the model are discussed in the light of the performance of teams implementing digital preservation repositories. It provides recommendations, guides and examples that may be useful for the implementation of digital preservation. It points to the need to strengthen the relationship between domain knowledge in digital preservation repositories with practices developed in numerous projects developed worldwide.

  11. Nonhomogeneous fractional Poisson processes

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaotian [School of Management, Tianjin University, Tianjin 300072 (China)]. E-mail: swa001@126.com; Zhang Shiying [School of Management, Tianjin University, Tianjin 300072 (China); Fan Shen [Computer and Information School, Zhejiang Wanli University, Ningbo 315100 (China)

    2007-01-15

    In this paper, we propose a class of non-Gaussian stationary increment processes, named nonhomogeneous fractional Poisson processes W{sub H}{sup (j)}(t), which permit the study of the effects of long-range dependance in a large number of fields including quantum physics and finance. The processes W{sub H}{sup (j)}(t) are self-similar in a wide sense, exhibit more fatter tail than Gaussian processes, and converge to the Gaussian processes in distribution in some cases. In addition, we also show that the intensity function {lambda}(t) strongly influences the existence of the highest finite moment of W{sub H}{sup (j)}(t) and the behaviour of the tail probability of W{sub H}{sup (j)}(t)

  12. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  13. Membrane Assisted Enzyme Fractionation

    DEFF Research Database (Denmark)

    Yuan, Linfeng

    . In this thesis, separations using crossflow elecro-membrane filtration (EMF) of amino acids, bovine serum albumin (BSA) and industrial enzymes from Novozymes were performed. The main objective of this study was to investigate the technological feasibility of EMF in the application of industrial enzyme...... fractionation, such as removal of a side activity from the main enzyme activity. As a proof-of-concept, amino acids were used as model solution to test the feasibility of EMF in the application of amphoteric molecule separation. A single amino acid was used to illustrate the effect of an electric field...... on the separation performance were very small in the investigated range. The mass transport of each enzyme can be well explained by the Extended-Nernst-Planck equation. Better separation was observed at lower feed concentration, higher solution pH in the investigated range and with a polysulfone (PS) MF membrane...

  14. Fractional Chemotaxis Diffusion Equations

    CERN Document Server

    Langlands, T A M

    2010-01-01

    We introduce mesoscopic and macroscopic model equations of chemotaxis with anomalous subdiffusion for modelling chemically directed transport of biological organisms in changing chemical environments with diffusion hindered by traps or macro-molecular crowding. The mesoscopic models are formulated using Continuous Time Random Walk master equations and the macroscopic models are formulated with fractional order differential equations. Different models are proposed depending on the timing of the chemotactic forcing. Generalizations of the models to include linear reaction dynamics are also derived. Finally a Monte Carlo method for simulating anomalous subdiffusion with chemotaxis is introduced and simulation results are compared with numerical solutions of the model equations. The model equations developed here could be used to replace Keller-Segel type equations in biological systems with transport hindered by traps, macro-molecular crowding or other obstacles.

  15. Analogue Realization of Fractional-Order Dynamical Systems

    Directory of Open Access Journals (Sweden)

    Ladislav Pivka

    2013-10-01

    Full Text Available As it results from many research works, the majority of real dynamical objects are fractional-order systems, although in some types of systems the order is very close to integer order. Application of fractional-order models is more adequate for the description and analysis of real dynamical systems than integer-order models, because their total entropy is greater than in integer-order models with the same number of parameters. A great deal of modern methods for investigation, monitoring and control of the dynamical processes in different areas utilize approaches based upon modeling of these processes using not only mathematical models, but also physical models. This paper is devoted to the design and analogue electronic realization of the fractional-order model of a fractional-order system, e.g., of the controlled object and/or controller, whose mathematical model is a fractional-order differential equation. The electronic realization is based on fractional-order differentiator and integrator where operational amplifiers are connected with appropriate impedance, with so called Fractional Order Element or Constant Phase Element. Presented network model approximates quite well the properties of the ideal fractional-order system compared with e.g., domino ladder networks. Along with the mathematical description, circuit diagrams and design procedure, simulation and measured results are also presented.

  16. RNA structure and scalar coupling constants

    Energy Technology Data Exchange (ETDEWEB)

    Tinoco, I. Jr.; Cai, Z.; Hines, J.V.; Landry, S.M.; SantaLucia, J. Jr.; Shen, L.X.; Varani, G. [Univ. of California, Berkeley, CA (United States)

    1994-12-01

    Signs and magnitudes of scalar coupling constants-spin-spin splittings-comprise a very large amount of data that can be used to establish the conformations of RNA molecules. Proton-proton and proton-phosphorus splittings have been used the most, but the availability of {sup 13}C-and {sup 15}N-labeled molecules allow many more coupling constants to be used for determining conformation. We will systematically consider the torsion angles that characterize a nucleotide unit and the coupling constants that depend on the values of these torsion angles. Karplus-type equations have been established relating many three-bond coupling constants to torsion angles. However, one- and two-bond coupling constants can also depend on conformation. Serianni and coworkers measured carbon-proton coupling constants in ribonucleosides and have calculated their values as a function of conformation. The signs of two-bond coupling can be very useful because it is easier to measure a sign than an accurate magnitude.

  17. Johnson Type Bounds on Constant Dimension Codes

    CERN Document Server

    Xia, Shu-Tao

    2007-01-01

    Very recently, an operator channel was defined by Koetter and Kschischang when they studied random network coding. They also introduced constant dimension codes and demonstrated that these codes can be employed to correct errors and/or erasures over the operator channel. Constant dimension codes are equivalent to the so-called linear authentication codes introduced by Wang, Xing and Safavi-Naini when constructing distributed authentication systems in 2003. In this paper, we study constant dimension codes. It is shown that Steiner structures are optimal constant dimension codes achieving the Wang-Xing-Safavi-Naini bound. Furthermore, we show that constant dimension codes achieve the Wang-Xing-Safavi-Naini bound if and only if they are certain Steiner structures. Then, we derive two Johnson type upper bounds, say I and II, on constant dimension codes. The Johnson type bound II slightly improves on the Wang-Xing-Safavi-Naini bound. Finally, we point out that a family of known Steiner structures is actually a fam...

  18. Inflation with a constant rate of roll

    Science.gov (United States)

    Motohashi, Hayato; Starobinsky, Alexei A.; Yokoyama, Jun'ichi

    2015-09-01

    We consider an inflationary scenario where the rate of inflaton roll defined by ̈phi/H dot phi remains constant. The rate of roll is small for slow-roll inflation, while a generic rate of roll leads to the interesting case of 'constant-roll' inflation. We find a general exact solution for the inflaton potential required for such inflaton behaviour. In this model, due to non-slow evolution of background, the would-be decaying mode of linear scalar (curvature) perturbations may not be neglected. It can even grow for some values of the model parameter, while the other mode always remains constant. However, this always occurs for unstable solutions which are not attractors for the given potential. The most interesting particular cases of constant-roll inflation remaining viable with the most recent observational data are quadratic hilltop inflation (with cutoff) and natural inflation (with an additional negative cosmological constant). In these cases even-order slow-roll parameters approach non-negligible constants while the odd ones are asymptotically vanishing in the quasi-de Sitter regime.

  19. The Erd\\H{o}s--Moser equation $1^k+2^k+...+(m-1)^k=m^k$ revisited using continued fractions

    CERN Document Server

    Gallot, Yves; Zudilin, Wadim

    2009-01-01

    If the equation of the title has an integer solution with $k\\ge2$, then $m>10^{9.3\\cdot10^6}$. This was the current best result and proved using a method due to L. Moser (1953). This approach cannot be improved to reach the benchmark $m>10^{10^7}$. Here we achieve $m>10^{10^9}$ by showing that $2k/(2m-3)$ is a convergent of $\\log2$ and making an extensive continued fraction digits calculation of $(\\log2)/N$, with $N$ an appropriate integer. This method is very different from that of Moser. Indeed, our result seems to give one of very few instances where a large scale computation of a numerical constant has an application.

  20. Design of a constant-voltage and constant-current controller with dual-loop and adaptive switching frequency control

    Science.gov (United States)

    Yingping, Chen; Zhiqian, Li

    2015-05-01

    A 5.0-V 2.0-A flyback power supply controller providing constant-voltage (CV) and constant-current (CC) output regulation without the use of an optical coupler is presented. Dual-close-loop control is proposed here due to its better regulation performance of tolerance over process and temperature compared with open loop control used in common. At the same time, the two modes, CC and CV, could switch to each other automatically and smoothly according to the output voltage level not sacrificing the regulation accuracy at the switching phase, which overcomes the drawback of the digital control scheme depending on a hysteresis comparator to change the mode. On-chip compensation using active capacitor multiplier technique is applied to stabilize the voltage loop, eliminate an additional package pin, and save on the die area. The system consumes as little as 100 mW at no-load condition without degrading the transient response performance by utilizing the adaptive switching frequency control mode. The proposed controller has been implemented in a commercial 0.35-μm 40-V BCD process, and the active chip area is 1.5 × 1.0 mm2. The total error of the output voltage due to line and load variations is less than ±1.7%.

  1. Some Applications of Fractional Calculus in Engineering

    Directory of Open Access Journals (Sweden)

    J. A. Tenreiro Machado

    2010-01-01

    Full Text Available Fractional Calculus (FC goes back to the beginning of the theory of differential calculus. Nevertheless, the application of FC just emerged in the last two decades, due to the progress in the area of chaos that revealed subtle relationships with the FC concepts. In the field of dynamical systems theory some work has been carried out but the proposed models and algorithms are still in a preliminary stage of establishment. Having these ideas in mind, the paper discusses FC in the study of system dynamics and control. In this perspective, this paper investigates the use of FC in the fields of controller tuning, legged robots, redundant robots, heat diffusion, and digital circuit synthesis.

  2. Leading Guard Digits in Finite-Precision Redundant Representations

    OpenAIRE

    Muller, Jean-Michel; Kornerup, Peter

    2006-01-01

    Redundant number representations are generally used to allow constant time additions, based on the fact that only bounded carry-ripples take place. But, carries may ripple out into positions which may not be needed to represent the final value of the result and, thus, a certain amount of leading guard digits are needed to correctly determine the result. Also, when cancellation during subtractions occurs, there may be nonzero digits in positions not needed to represent the result of the calcul...

  3. Digital Signal Processing Filtering Algorithm : Audio Equalization Using Matlab

    OpenAIRE

    Chaguaro Aldaz, Daniel

    2015-01-01

    The contemporary domain of Digital Signal Processing is in constant influx and trying to find new applications that will benefit the everyday life of ordinary people. In modern technology, most of the electronic processes use DSP algorithms in order to collect analogue information that is continually present all around us and convert it into a digital form. The need of understanding the basics of how these processes occur, has inspired to implement a DSP application for educational and testin...

  4. Ageing and digital games

    DEFF Research Database (Denmark)

    Iversen, Sara Mosberg

    2016-01-01

    Digital games are still to a great degree considered a medium mainly for young boys. However, available statistics on Western media use show that this is far from the case. Increasingly, people of all ages and genders play digital games, also older adults in their early 60s and beyond. The aim...... of the book is to examine, analyse and discuss: 1) What older adults do with digital games and what meanings the use of digital games take on in the everyday life of older adults; 2) How older adults are perceived by society in relation to digital games; 3) How play and games can be used both...

  5. Digital Living at Home

    DEFF Research Database (Denmark)

    Andersen, Pernille Viktoria Kathja; Christiansen, Ellen Tove

    2013-01-01

    Does living with digital technology inevitably lead to digital living? Users talking about a digital home control system, they have had in their homes for eight years, indicate that there is more to living with digital technology than a functional-operational grip on regulation. Our analysis...... of these user voices has directed us towards a ‘home-keeping’ design discourse, which opens new horizons for design of digital home control systems by allowing users to perform as self-determined controllers and groomers of their habitat. The paper concludes by outlining the implications of a ‘home...

  6. Void fraction prediction in saturated flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Francisco J Collado [Dpto de Ingenieria Mecanica-Motores Termicos, CPS-B, Universidad de Zaragoza, Maria de Luna 50018-Zaragoza (Spain)

    2005-07-01

    Full text of publication follows: An essential element in thermal-hydraulics is the accurate prediction of the vapor void fraction, or fraction of the flow cross-sectional area occupied by steam. Recently, the author has suggested to calculate void fraction working exclusively with thermodynamic properties. It is well known that the usual 'flow' quality, merely a mass flow rate ratio, is not at all a thermodynamic property because its expression in function of thermodynamic properties includes the slip ratio, which is a parameter of the process not a function of state. By the other hand, in the classic and well known expression of the void fraction - in function of the true mass fraction of vapor (also called 'static' quality), and the vapor and liquid densities - does not appear the slip ratio. Of course, this would suggest a direct procedure for calculating the void fraction, provided we had an accurate value of the true mass fraction of vapor, clearly from the heat balance. However the classic heat balance is usually stated in function of the 'flow' quality, what sounds really contradictory because this parameter, as we have noted above, is not at all a thermodynamic property. Then we should check against real data the actual relationship between the thermodynamic properties and the applied heat. For saturated flow boiling just from the inlet of the heated tube, and not having into account the kinetic and potential terms, the uniform applied heat per unit mass of inlet water and per unit length (in short, specific linear heat) should be closely related to a (constant) slope of the mixture enthalpy. In this work, we have checked the relation between the specific linear heat and the thermodynamic enthalpy of the liquid-vapor mixture using the actual mass fraction. This true mass fraction is calculated using the accurate measurements of the outlet void fraction taken during the Cambridge project by Knights and Thom in the sixties for

  7. Fractionation of Stable Isotopes in Atmospheric Aerosol Reactions

    DEFF Research Database (Denmark)

    Meusinger, Carl

    reactions and undergo complex chemical and physical changes during their lifetimes. In order to assess processes that form and alter aerosols, information provided by stable isotopes can be used to help constrain estimates on the strength of aerosol sources and sinks. This thesis studies (mass......-independent) fractionation processes of stable isotopes of C, N, O and S in order to investigate three different systems related to aerosols: 1. Post-depositional processes of nitrate in snow that obscure nitrate ice core records 2. Formation and aging of secondary organic aerosol generated by ozonolysis of X...... as required. The kndings provide important results for the studies' respective felds, including a description of the isotopic fractionation and quantum yield of nitrate photolysis in snow, equilibrium fractionation in secondary organic aerosol and fractionation constants of different oxidation pathways of SO2....

  8. Digital Radiation image

    Directory of Open Access Journals (Sweden)

    Abou-Bakr Ramadan

    2012-03-01

    Full Text Available This work introduces a new way for data visualization. Its name is Digital Application name' Image. Normal digital image is created by digital camera or digital scanner but digital application name image is created by measurements of monitoring data. This work uses the data which is measured by radiation monitoring station and classifies it using fuzzy logic rules to create digital radiation image. The main unique advantage of digital radiation image is that it expresses thousands of measurements in a very clear form through only one picture while the maximum number of measurements does not exceed 100 with other conventional visualization methods. This feature gives a facility to view one year of all recorded measurements in only one photo. This picture helps the user to observe the behavior of thousands of measurements in few minutes instead of spending few hours for reviewing hundreds of charts for the same measurements.

  9. Digital gaming expertise

    DEFF Research Database (Denmark)

    Toft-Nielsen, Claus

    , to have access to the dynamic power systems in and around digital games theorized as ‘gaming capital’ (Consalvo, 2007) and who cannot? I argue, in other words, for an understanding of digital gaming competence as a reflection, negotiation, and production of gendered power relations, performed in ways......In a digitally saturated environment digital media users of all kinds, engaged in different areas of activity, are increasingly categorized in terms of their ability to appropriate and use digital media – they are regarded as non-users, experts, natives, or literates for instance. Within...... communication and game studies there are multiple understandings of how digital expertise is expressed and performed, and subsequently how these expressions and performances can be valued, understood and theorized within the research community. Among other things expertise with and within digital games has...

  10. Fractional Calculus: Integral and Differential Equations of Fractional Order

    CERN Document Server

    Gorenflo, Rudolf

    2008-01-01

    We introduce the linear operators of fractional integration and fractional differentiation in the framework of the Riemann-Liouville fractional calculus. Particular attention is devoted to the technique of Laplace transforms for treating these operators in a way accessible to applied scientists, avoiding unproductive generalities and excessive mathematical rigor. By applying this technique we shall derive the analytical solutions of the most simple linear integral and differential equations of fractional order. We show the fundamental role of the Mittag-Leffler function, whose properties are reported in an ad hoc Appendix. The topics discussed here will be: (a) essentials of Riemann-Liouville fractional calculus with basic formulas of Laplace transforms, (b) Abel type integral equations of first and second kind, (c) relaxation and oscillation type differential equations of fractional order.

  11. An improved fractional divider for fractional-N frequency synthesizers

    Science.gov (United States)

    Zhang, Wei; Liu, Yang; Zhou, Yongqi

    2009-07-01

    This paper presents an improved fractional divider used in 1.8~2GHz fractional-N frequency synthesizers. A new clock setting for delta-sigma modulator (DSM) is proposed to prevent the potential problems of traditional fractional dividers: the DSM output would be wrongly loaded and the action of DSM circuit may affect the phase-detection of phase-frequency-detector (PFD). Simulation result shows the effectiveness of this improvement.

  12. Digital Collections, Digital Libraries and the Digitization of Cultural Heritage Information.

    Science.gov (United States)

    Lynch, Clifford

    2002-01-01

    Discusses the development of digital collections and digital libraries. Topics include digitization of cultural heritage information; broadband issues; lack of compelling content; training issues; types of materials being digitized; sustainability; digital preservation; infrastructure; digital images; data mining; and future possibilities for…

  13. Environment-Dependent Fundamental Physical Constants

    CERN Document Server

    Terazawa, Hidezumi

    2012-01-01

    A theory of special inconstancy, in which some fundamental physical constants such as the fine-structure and gravitational constants may vary, is proposed in pregeometry. In the special theory of inconstancy, the \\alpha-G relation of \\alpha=3\\pi/[16ln(4\\pi/5GM_W^2)] between the varying fine-structure and gravitaional constants (where M_W is the charged weak boson mass) is derived from the hypothesis that both of these constants are related to the same fundamental length scale in nature. Furthermore, it leads to the prediction of dot{{\\alpha}}/\\alpha=(-0.8\\pm2.5)\\times10^{-14}yr^{-1} from the most precise limit of dot{G}/G=(-0.6\\pm2.0)\\times10^{-12}yr^{-1} by Thorsett, which is not only consistent with the recent observation of dot{{\\alpha}}/\\alpha=(0.5\\pm0.5)\\times10^{-14}yr^{-1} by Webb et al. but also feasible for future experimental tests. Also a theory of general inconstancy, in which any fundamental physical constants may vary, is proposed in "more general relativity", by assuming that the space-time is ...

  14. Athermal nonlinear elastic constants of amorphous solids.

    Science.gov (United States)

    Karmakar, Smarajit; Lerner, Edan; Procaccia, Itamar

    2010-08-01

    We derive expressions for the lowest nonlinear elastic constants of amorphous solids in athermal conditions (up to third order), in terms of the interaction potential between the constituent particles. The effect of these constants cannot be disregarded when amorphous solids undergo instabilities such as plastic flow or fracture in the athermal limit; in such situations the elastic response increases enormously, bringing the system much beyond the linear regime. We demonstrate that the existing theory of thermal nonlinear elastic constants converges to our expressions in the limit of zero temperature. We motivate the calculation by discussing two examples in which these nonlinear elastic constants play a crucial role in the context of elastoplasticity of amorphous solids. The first example is the plasticity-induced memory that is typical to amorphous solids (giving rise to the Bauschinger effect). The second example is how to predict the next plastic event from knowledge of the nonlinear elastic constants. Using the results of our calculations we derive a simple differential equation for the lowest eigenvalue of the Hessian matrix in the external strain near mechanical instabilities; this equation predicts how the eigenvalue vanishes at the mechanical instability and the value of the strain where the mechanical instability takes place.

  15. MID IR Optical Constants of Orthopyroxenes.

    Science.gov (United States)

    Rucks, M.; Glotch, T. D.

    2014-12-01

    Orthopyroxenes are common rock forming minerals that are present on many planetary bodies as well as meteorites and cosmic dust. The presence of these minerals can give implications to the petrogenic history of these planetary bodies. Optical constants, n and k, are essential inputs into radiative transfer models which are used in remote sensing techniques. [1,2] While optical constants have been determined for orthopyroxenes with high Mg content, Fe rich orthopyroxenes have not been studied as extensively. [3] The goal of this research is to determine the optical constants of orthopyroxenes ranging in composition along the enstatite-ferrosilite solid solution, to gain a more comprehensive list of these values. Specular reflectance spectra, in the range of 250-4000 cm-1, were obtained for several oriented single crystal samples at three crystallographic orientations for each sample. Optical constants, n and k, were then derived through modeling of measured spectra using the Matlab lsqcurvefit function. Preveous work has identified the optical constants for two Mg rich natural samples, enstatite and hypersthene. Current research applies the above methodology to synthetic ferrosilite, the Fe rich end-member of the orthopyroxene mineral series. Future studies will provide a more comprehensive look at the variation of n and k as a function of the Mg:Fe composition. [1] Arnold, J.A. et al (2013) (under review), [2] Glotch, T.D. and Rossman, G.R. (2009) Icarus, [3] Jäger, C. et al (1998) Astron. Astrophys.

  16. Digital rights management for digital cinema

    Science.gov (United States)

    Kirovski, Darko; Peinado, Marcus; Petitcolas, Fabien A. P.

    2001-12-01

    There is a wide consensus among the feature film production studios that the Internet era brings a new paradigm for film distribution to cinemas worldwide. The benefits of digital cinema to both producers and cinemas are numerous: significantly lower distribution and maintenance costs, immediate access to film libraries, higher presentation quality, and strong potential for developing new business models. Despite these advantages, the studios are still reluctant to jump into the digital age. The main showstopper for digital cinema is the danger of widespread piracy. Piracy already costs Hollywood an estimated two billion dollars annually and digital cinema without proper copyright enforcement could increase this number. In this paper, we present a copyright management system that aims at providing the set of necessary security tools: standard cryptographic primitives and copyright protection mechanisms that enable a reliable and secure feature film delivery system.

  17. Best of Digital British Columbia : Digitization Around the Province

    OpenAIRE

    2011-01-01

    The Online Dictionary of Library and Information Science defines digitization as “the process of converting data to digital format for processing by a computer.” We have all heard about mass digitization projects such as the Google Digitization Project and Project Gutenberg, but local ’boutique’ digitization efforts do not receive as much fanfare. Digitization projects completed in BC showcase the unique culture and history of British Columbia. The BC Digitization Coalition is a new initiativ...

  18. The case for the cosmological constant

    Indian Academy of Sciences (India)

    Varun Sahni

    2000-07-01

    I present a short overview of current observational results and theoretical models for a cosmological constant. The main motivation for invoking a small cosmological constant (or -term) at the present epoch has to do with observations of high redshift Type Ia supernovae which suggest an accelerating universe. A flat accelerating universe is strongly favoured by combining supernovae observations with observations of CMB anisotropies on degree scales which give the `best-fit’ values ≃ 0.7 and m ≃ 0.3. A time dependent cosmological -term can be generated by scalar field models with exponential and power law potentials. Some of these models can alleviate the `fine tuning’ problem which faces the cosmological constant.

  19. Bounds on Gromov Hyperbolicity Constant in Graphs

    Indian Academy of Sciences (India)

    José M Rodríguez; José M Sigarreta

    2012-02-01

    If is a geodesic metric space and 1,2,3 $\\in$ , a geodesic triangle ={1,2,3} is the union of the three geodesics [1,2], [2,3] and [31] in . The space is -hyperbolic (in the Gromov sense) if any side of is contained in a -neighborhood of the union of two other sides, for every geodesic triangle in . If is hyperbolic, we denote by () the sharp hyperbolicity constant of , i.e. ()=$inf{$≥ 0$ : is -hyperbolic}. In this paper we relate the hyperbolicity constant of a graph with some known parameters of the graph, as its independence number, its maximum and minimum degree and its domination number. Furthermore, we compute explicitly the hyperbolicity constant of some class of product graphs.

  20. Time constant measurement for control of induction heating processes for thixoforming

    Science.gov (United States)

    Gerlach, O.; Lechler, A.; Verl, A.

    2015-02-01

    In controlling induction heating systems, several measurement methods exist for controlled heating of metal billets into the semi-solid state for thixoforming. The most common approach is to measure the billet temperature, which suffers from various drawbacks leading to difficulties in process stability. The main disadvantages are the small temperature range of the process window and the alloy composition dependency of the correlation between temperature and liquid fraction. An alternative is to determine the liquid fraction of the billet by measuring the time constant of the load. Although time constant measurement is not affected by the mentioned problems, it is difficult to use it as a controlled variable. This paper shows that disturbances affecting time constant measurement are mainly caused by semiconductor losses inside the inverter. A method is introduced to compensate these losses. This method was implemented and tested in the embedded system of an induction heating unit, thereby showing that it is possible to use time constant measurement to determine the liquid fraction of a billet during induction heating.