Sun, 27 Jul 2008 06:07:21 BST CiteULike: Tag oscillator http://www.citeulike.org/tag/oscillator CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/xico/article/1103966 <i>Annu Rev Genet, Vol. 40 (2006), pp. 409-448.</i><br /><br />This review examines the connections between circadian and metabolic rhythms. Examples from a wide variety of well-studied organisms are used to illustrate some of the genetic and molecular pathways linking circadian timekeeping to metabolism. The principles underlying biological timekeeping by intrinsic circadian clocks are discussed briefly. Genetic and molecular studies have unambiguously identified the importance of gene expression feedback circuits to the generation of overt circadian rhythms. This is illustrated particularly well by the results of genome-wide expression studies, which have uncovered hundreds of clock-controlled genes in cyanobacteria, fungi, plants, and animals. The potential connections between circadian oscillations in gene expression and circadian oscillations in metabolic activity are a major focus of this review. Interplay of circadian clocks and metabolic rhythms. H Wijnen MW Young doi:10.1146/annurev.genet.40.110405.090603 Annu Rev Genet, Vol. 40 (2006), pp. 409-448. 2007-02-13T02:00:10-00:00 2006 Annu Rev Genet 0066-4197 40 409 448 circadian clock metabolism oscillator periodic review rhythm http://www.citeulike.org/user/summerxia/article/834240 <i>Custom Integrated Circuits Conference, 1998., Proceedings of the IEEE 1998 (1998), pp. 503-506.</i><br /><br />A low-power and low-voltage (LP/LV) RF front-end operating at 430 MHz and implemented in a standard 0.5 μm digital CMOS process is described. Specific LP/LV bias techniques and design tradeoffs are discussed and their application to the design of a fully integrated direct-conversion receiver is presented. The RF building blocks including a 200 μA LNA, two different 50 μA mixers and a ring-oscillator with differential I-Q outputs consuming 300 μA at 430 MHz, have been manufactured and their performances measured. Taking into account the severe power budget, a total double sideband (DSB) noise figure of 17 dB was achieved, together with a spurious free dynamic range of 55 dB at 60 kHz bandwidth, which is sufficient for the targeted application A 1.3 V low-power 430 MHz front-end using a standard digital CMOS process [ISM wireless link] T Melly AS Porret CC Enz M Kayal Custom Integrated Circuits Conference, 1998., Proceedings of the IEEE 1998 (1998), pp. 503-506. 2006-09-07T23:23:12-00:00 1998 Custom Integrated Circuits Conference, 1998., Proceedings of the IEEE 1998 503 506 low-power oscillator http://www.citeulike.org/user/summerxia/article/834237 <i>Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE (2004), pp. 579-582.</i><br /><br />Low power RF operation is often limited by the poor quality factor of the passives available in silicon-based processes. This paper reports on an LC-tank VCO, incorporating micromachined inductors and capacitors, for low power operation, without sacrificing performance. Only 2.75 mW of power is needed to achieve -122 dB/Hz phase noise at 1 MHz from a 2.84 GHz carrier. Low-power LC-VCO using integrated MEMS passives VK Saraf D Ramachandran A Oz GK Fedder T Mukherjee Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE (2004), pp. 579-582. 2006-09-07T23:20:56-00:00 2004 Radio Frequency Integrated Circuits (RFIC) Symposium, 2004. Digest of Papers. 2004 IEEE 579 582 low-power oscillator http://www.citeulike.org/user/summerxia/article/423791 <i>Sensors and Actuators A: Physical, Vol. 76, No. 1-3. (30 August 1999), pp. 437-441.</i><br /><br />A novel CMOS oscillator has been developed to be used in integrated capacitive sensor interfaces. The proposed topology has been designed in order to operate at a reduced supply voltage (the minimum being 1.2 V) with low power consumption. A 1.4-V design with an overall power consumption of only 23 [mu]W is presented. A five decades capacitive range (10 fF-100 pF), to which corresponds a frequency span of about 300 Hz-3 MHz, has been considered. The circuit shows low noise, low sensitivity to supply voltage variations and good output linearity. These characteristics have been verified to be fully satisfactory if compared to corresponding performance of two other typical solutions presented in literature. A novel low voltage low power oscillator as a capacitive sensor interface for portable applications Giuseppe Ferri Pierpaolo De Laurentiis doi:10.1016/S0924-4247(98)00368-9 Sensors and Actuators A: Physical, Vol. 76, No. 1-3. (30 August 1999), pp. 437-441. 2005-12-06T23:39:38-00:00 1999 Sensors and Actuators A: Physical 76 1-3 437 441 capacitive low-power low-voltage oscillator sensor http://www.citeulike.org/user/stajich/article/984701 <i>Nat Rev Genet, Vol. 6, No. 7. (July 2005), pp. 544-556.</i> CIRCADIAN RHYTHMS FROM MULTIPLE OSCILLATORS: LESSONS FROM DIVERSE ORGANISMS Deborah Bell-Pedersen Vincent Cassone David Earnest Susan Golden Paul Hardin Terry Thomas Mark Zoran doi:10.1038/nrg1633 Nat Rev Genet, Vol. 6, No. 7. (July 2005), pp. 544-556. 2006-12-08T19:40:46-00:00 2005 Nat Rev Genet 6 7 544 556 circadian fungi multicellular oscillator http://www.citeulike.org/user/rodney/article/1526050 <i>Journal of the Optical Society of America B Optical Physics, Vol. 12 (September 1995), pp. 1723-1731.</i><br /><br />Available on OSA CDROM High-repetition-rate femtosecond optical parametric oscillator-amplifier system near 3 m m GR Holtom RA Crowell XS Xie Journal of the Optical Society of America B Optical Physics, Vol. 12 (September 1995), pp. 1723-1731. 2007-08-01T02:00:41-00:00 1995 Journal of the Optical Society of America B Optical Physics 12 1723 1731 3 amplifier femtosecond micron optical oscillator parametric http://www.citeulike.org/user/rodney/article/2186960 <i>Physical Review E, Vol. 68, No. 2. (2003), 025201.</i><br /><br />We investigate the characteristics of temporal phase locking states observed in the route to phase synchronization. It is found that before phase synchronization there is a periodic phase synchronization state characterized by periodic appearance of temporal phase-locking state and that the state leads to local negativeness in one of the vanishing Lyapunov exponents. By taking a statistical measure; we present the evidences of the phenomenon in unidirectionally and mutually coupled chaotic oscillators; respectively. And it is qualitatively discussed that the phenomenon is described by a nonuniform oscillator model in the presence of noise. Periodic phase synchronization in coupled chaotic oscillators Won-Ho Kye Dae-Sic Lee Sunghwan Rim Chil-Min Kim Young-Jai Park doi:10.1103/PhysRevE.68.025201 Physical Review E, Vol. 68, No. 2. (2003), 025201. 2008-01-02T04:56:10-00:00 2003 Physical Review E 68 2 025201 American Physical Society chaos nonuniform oscillator periodic synchronization http://www.citeulike.org/user/rodney/article/1473994 <i>Physical Review Letters, Vol. 93, No. 14. (2004)</i><br /><br />We report on the characterization of nanometer-scale resonators. Each device incorporates one multiwalled carbon nanotube (MWNT) as a torsional spring. The devices are actuated electrostatically, and their deflections, both low frequency and on resonance, are detected optically. These are some of the smallest electromechanical devices ever created and are a demonstration of practical integrated MWNT-based oscillators. The results also show surprising intershell mechanical coupling behavior in the MWNTs. Resonant Oscillators with Carbon-Nanotube Torsion Springs SJ Papadakis AR Hall PA Williams L Vicci MR Falvo R Superfine S Washburn doi:10.1103/PhysRevLett.93.146101 Physical Review Letters, Vol. 93, No. 14. (2004) 2007-07-22T23:54:31-00:00 2004 Physical Review Letters 93 14 APS carbon nanotubes oscillator resonance torque torsion http://www.citeulike.org/user/rodney/article/1074603 <i>Applied Physics Letters, Vol. 88, No. 4. (2006)</i><br /><br />Simple models are presented for estimating viscous damping of fluid (gas or liquid) loaded mechanical resonators. The models apply to beams in flexural modes of vibration, and to thin beams and plates in longitudinal modes of vibration. Predictions of the associated quality factor are compared with measured values for several macroscale and microscale resonators. The scaling of viscous loss with oscillator size is discussed. The minimum detectable mass is estimated for several oscillator designs and it is shown that, for comparably sized devices, longitudinal resonators have the lowest threshold of detection. This minimum detectable mass is proportional to scale to the power 1.75 for all resonator architectures limited by viscous damping, and it is shown that the viscous loss is 220 times larger in water than in air. ©2006 American Institute of Physics Effect of viscous loss on mechanical resonators designed for mass detection Joseph Vignola John Judge Jacek Jarzynski Maxim Zalalutdinov Brian Houston Jeffrey Baldwin doi:10.1063/1.2165186 Applied Physics Letters, Vol. 88, No. 4. (2006) 2007-01-29T15:56:41-00:00 2006 Applied Physics Letters 88 4 AIP detection mass oscillator resonator viscosity http://www.citeulike.org/user/rodney/article/1720385 <i>Physical Review B (Condensed Matter and Materials Physics), Vol. 76, No. 11. (2007)</i><br /><br />We studied the dynamical response of a nanomechanical resonator to biomolecular (e.g., DNA) adsorptions on a resonator's surface by using theoretical model, which considers the Hamiltonian H such that the potential energy consists of elastic bending energy of a resonator and the potential energy for biomolecular interactions. It was shown that the resonant frequency shift for a resonator due to biomolecular adsorption depends on not only the mass of adsorbed biomolecules but also the biomolecular interactions. Specifically, for double-stranded DNA adsorption on a resonator's surface, the resonant frequency shift is also dependent on the ionic strength of a solvent, implying the role of biomolecular interactions on the dynamic behavior of a resonator. This indicates that nanomechanical resonators may enable one to quantify the biomolecular mass, implying the enumeration of biomolecules, as well as gain insight into intermolecular interactions between adsorbed biomolecules on the surface. Dynamical response of nanomechanical resonators to biomolecular interactions Kilho Eom Tae Kwon Dae Yoon Hong Lee Tae Kim doi:10.1103/PhysRevB.76.113408 Physical Review B (Condensed Matter and Materials Physics), Vol. 76, No. 11. (2007) 2007-10-02T18:03:09-00:00 2007 Physical Review B (Condensed Matter and Materials Physics) 76 11 APS biomolecules dynamics interactions mechanical nanoscale oscillator resonators http://www.citeulike.org/user/pak/article/3006336 <i>Physical Review A, Vol. 43, No. 11. (1 June 1991), 6194.</i> Quantum dynamics of the parametric oscillator P Kinsler PD Drummond doi:10.1103/PhysRevA.43.6194 Physical Review A, Vol. 43, No. 11. (1 June 1991), 6194. 2008-07-15T16:37:34-00:00 1991 Physical Review A 43 11 6194 American Physical Society optics oscillator parametric physics quantum quasiprobability tunneling http://www.citeulike.org/user/nrt63/article/950794 <i>Physics of Plasmas, Vol. 6, No. 8. (1999), pp. 3358-3368.</i><br /><br />Self-amplification of coherent spontaneous emission and shot noise in high gain single pass free electron lasers is investigated using a multifrequency model. This approach includes intrinsically the coherent spontaneous emission generated by the components of the Fourier transform of electron current that are close to the resonant frequency. The shot noise is modeled by adding random fluctuations to the initial electron phases. The complete model of equations is derived and analytical and numerical results are presented. The main features of the emitted radiation starting from coherent spontaneous emission and shot noise are discussed. ©1999 American Institute of Physics. High gain free electron laser amplifiers starting from coherent and incoherent spontaneous emission Nicola Piovella doi:10.1063/1.873575 Physics of Plasmas, Vol. 6, No. 8. (1999), pp. 3358-3368. 2006-11-18T11:51:17-00:00 1999 Physics of Plasmas 6 8 3358 3368 AIP chaos cycle dynamical limit oscillator system http://www.citeulike.org/user/michaelbussmann/article/2443899 <i>(19 April 2006)</i><br /><br />Written from an industrial perspective, Solid-State Laser Engineering discusses in detail the characteristics, design, construction, and performance of solid-state lasers. Emphasis is placed on engineering and practical considerations; phenomenological aspects using models are preferred to abstract mathematical derivations. Since its first edition almost 30 years ago this book has become the standard in the field of solid-state lasers for scientists,engineers and graduate students.</P> <P>This new edition has been extensively revised and updated to account for recent developments in the areas of diode-laser pumping, laser materials and nonlinear crystals. Completely new sections have been added dealing with frequency control, the theory of mode-locking, femto second lasers, high efficiency harmonic generation, passive and acousto-optic Q-switching, semiconductor saturable absorber mirrors (SESAM) and peridically poled nonlinear crystals. Solid-State Laser Engineering (Springer Series in Optical Sciences) Walter Koechner (19 April 2006) 2008-02-28T15:09:55-00:00 2006 Springer amplification chirp cpa damage diode laser mode-locking nonlinear optical oscillator pulse pumping q-switch resonator self-focusing solid-state thermo-optic http://www.citeulike.org/user/michaelbussmann/article/2874846 <i>Physical Review Letters, Vol. 100, No. 22. (2008)</i><br /><br />We provide a complete characterization of the evolution of entanglement between two resonant oscillators coupled to a common environment. We identify three phases with different qualitative long time behavior: There is a phase where entanglement undergoes a sudden death. Another phase (sudden death and revival) is characterized by an infinite sequence of events of sudden death and revival of entanglement. In the third phase (no sudden death) there is no sudden death of entanglement, which persists for a long time. The phase diagram is described and analytic expressions for the boundary between phases are obtained. These results are applicable to a large variety of non-Markovian environments. The case of nonresonant oscillators is also numerically investigated. Dynamics of the Entanglement between Two Oscillators in the Same Environment Juan Paz Augusto Roncaglia doi:10.1103/PhysRevLett.100.220401 Physical Review Letters, Vol. 100, No. 22. (2008) 2008-06-09T08:17:28-00:00 2008 Physical Review Letters 100 22 APS entanglement oscillator http://www.citeulike.org/user/mesominimax/article/205531 <i>Proc Natl Acad Sci U S A, Vol. 101, No. 30. (27 July 2004), pp. 10955-10960.</i><br /><br />Diverse biochemical rhythms are generated by thousands of cellular oscillators that somehow manage to operate synchronously. In fields ranging from circadian biology to endocrinology, it remains an exciting challenge to understand how collective rhythms emerge in multicellular structures. Using mathematical and computational modeling, we study the effect of coupling through intercell signaling in a population of Escherichia coli cells expressing a synthetic biological clock. Our results predict that a diverse and noisy community of such genetic oscillators interacting through a quorum-sensing mechanism should self-synchronize in a robust way, leading to a substantially improved global rhythmicity in the system. As such, the particular system of coupled genetic oscillators considered here might be a good candidate to provide the first quantitative example of a synchronization transition in a population of biological oscillators. Modeling a synthetic multicellular clock: repressilators coupled by quorum sensing. J Garcia-Ojalvo MB Elowitz SH Strogatz doi:10.1073/pnas.0307095101 Proc Natl Acad Sci U S A, Vol. 101, No. 30. (27 July 2004), pp. 10955-10960. 2005-05-19T20:52:27-00:00 2004 Proc Natl Acad Sci U S A 0027-8424 101 30 10955 10960 biocontrol oscillator quarum-sensing repressilator synchonization http://www.citeulike.org/user/martinthesis/article/2650022 <i>Physical Review A, Vol. 65, No. 5. (3 May 2002), 052316.</i> Quantum encodings in spin systems and harmonic oscillators Stephen Bartlett Hubert de Guise Barry Sanders doi:10.1103/PhysRevA.65.052316 Physical Review A, Vol. 65, No. 5. (3 May 2002), 052316. 2008-04-10T17:32:33-00:00 2002 Physical Review A 65 5 052316 American Physical Society computation harmonic micromaser oscillator quantum qudit http://www.citeulike.org/user/mairr/article/2857003 <i>Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International (1995), pp. 565-568.</i><br /><br />This paper presents a reduction method of the start-up time after the switch-on of the D.C. power supply of a crystal oscillator circuit. It is shown that a fast start-up crystal oscillator can easily be obtained by changing only the circuit connection of the crystal resonator. The new scheme can be applied to the usual Colpitts crystal oscillator circuits, to the cascode crystal oscillator circuits, and also to the overtone crystal oscillator circuits Fast start-up crystal oscillator circuits Y Tsuzuki T Adachi Ji Zhang doi:10.1109/FREQ.1995.484055 Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International (1995), pp. 565-568. 2008-06-02T13:49:08-00:00 1995 Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International 565 568 crystal fast-start-up oscillator http://www.citeulike.org/user/LWelch/article/3008534 <i>(15 Jul 2008)</i><br /><br />An oscillator model for the relativistic two-body system composed of the spin-1/2 and spin-0 particles has been constructed. This system is described by the wave equation derived with the extension of the SL(2,C) group to the Sp(4,C) one. An oscillator-type solution to this equation has been obtained for a combination of the Lorentz-vector and Lorentz-tensor interaction potentials. The particular cases of the pure Lorentz-vector and pure Lorentz-tensor interaction have been considered. It was found that in the case of the pure Lorentz-tensor potential the constructed model can be regarded as the two-body generalization of the one-body Dirac oscillator. Oscillator model for the relativistic fermion-boson system DA Kulikov RS Tutik (15 Jul 2008) 2008-07-16T13:48:21-00:00 2008 oscillator http://www.citeulike.org/user/LWelch/article/2985677 <i>(5 Jan 2007)</i><br /><br />Two-Body Dirac equations of constraint dynamics provide a covariant framework to investigate the problem of highly relativistic quarks in meson bound states. This formalism eliminates automatically the problems of relative time and energy, leading to a covariant three dimensional formalism with the same number of degrees of freedom as appears in the corresponding nonrelativistic problem. It provides bound state wave equations with the simplicity of the nonrelativistic Schroedinger equation. Unlike other three-dimensional truncations of the Bethe-Salpeter equation, this covariant formalism has been thoroughly tested in nonperturbatives contexts in QED, QCD, and nucleon-nucleon scattering. Here we continue the important studies of this formalism by extending a method developed earlier for positronium decay into two photons to tests on the sixteen component quarkonium wave function solutions obtained in meson spectroscopy. We examine positronium decay and then the two-gamma quarkonium decays of eta_c, eta'_c, chi_0c, chi_2c, and pi-zero The results for the pi-zero, although off the experimental rate by 13%, is much closer than the usual expectations from a potential model. Two gamma quarkonium and positronium decays with Two-Body Dirac equations of constraint dynamics Horace Crater Cheuk-Yin Wong (5 Jan 2007) 2008-07-10T17:42:34-00:00 2007 oscillator http://www.citeulike.org/user/LWelch/article/2985661 <i>(18 Dec 2007)</i><br /><br />In the present work we obtain a new representation for the Dirac oscillator based on the Clifford algebra $C\ell_7.$ The symmetry breaking and the energy eigenvalues for our model of the Dirac oscillator are studied in the non-relativistic limit. On the Dirac Oscillator de Lima (18 Dec 2007) 2008-07-10T17:26:57-00:00 2007 oscillator http://www.citeulike.org/user/LWelch/article/2985532 <i>(3 Oct 1995)</i><br /><br />Some years ago, one of the authors~(MM) revived a concept to which he gave the name of single-particle Dirac oscillator, while another~(CQ) showed that it corresponds to a realization of supersymmetric quantum mechanics. The Dirac oscillator in its one- and many-body versions has had a great number of applications. Recently, it included the analytic expression for the eigenstates and eigenvalues of a two-particle system with a new type of Dirac oscillator interaction of frequency~$ω$. By considering the latter together with its partner corresponding to the replacement of~$ω$ by~$-ω$, we are able to get a supersymmetric formulation of the problem and find the superalgebra that explains its degeneracy. Supersymmetry and superalgebra for the two-body system with a Dirac oscillator interaction M Moshinsky C Quesne Yu (3 Oct 1995) 2008-07-10T15:57:19-00:00 1995 oscillator http://www.citeulike.org/user/LWelch/article/2985521 <i>(3 Feb 2005)</i><br /><br />We discusse a relativistic Hamiltonian for an n-body problem in which all the masses are equal and all spins take value 1/2. In the frame of reference in which the total momentum $P=0$, the Foldy-Wouthuysen transformation is applies and the positive energy part of the Hamiltonian is separated. The Hamiltonian with unharmonic oscillator potential is applied to describe mass differences for charmonium and bottonium states. The many body problem in relativistic quantum mechanics Marcos Moshinsky Anatoly Nikitin (3 Feb 2005) 2008-07-10T15:52:53-00:00 2005 oscillator http://www.citeulike.org/user/LWelch/article/2985644 <i>(18 Jun 2008)</i><br /><br />Undergraduate quantum mechanics tends to focus on the Schrödinger wave function. That is, in a typical introductory course, the Schrödinger differential equation is solved for a number of simple examples, usually in one dimension (1D). Then a 'formal' section is discussed, which introduces the notion of a Hilbert space, a basis set, adjoint operators, etc. This part is often mathematical, with some 'lip service' paid through examples like the matrix representation of Dirac's raising and lowering operators, or the angular momentum operators. The purpose of this paper is to introduce some of the same 1D examples, formulated as concrete matrix diagonalization problems, with a basis which consists of the infinite square well eigenfunctions. These examples demonstrate that undergraduate students are perfectly well equipped to handle such problems, in scenarios that are already familiar to them. We pay special attention to the one dimensional harmonic oscillator. After understanding the contents of this paper, a student should be well equipped to solve for low lying bound states of any 1D short range potential. The Harmonic Oscillator in Quantum Mechanics: the Third Way F Marsiglio (18 Jun 2008) 2008-07-10T17:07:36-00:00 2008 oscillator http://www.citeulike.org/user/LWelch/article/2986295 <i>(3 May 2004)</i><br /><br />We obtain the two-point Green's function for the relativistic Dirac-Oscillator problem. This is accomplished by setting up the relativistic problem in such a way that makes comparison with the nonrelativistic problem highly transparent and results in a map of the latter into the former. The relativistic bound states energy spectrum is obtained by locating the energy poles of this Green's function in a simple and straightforward manner. The Dirac-Oscillator Green's function AD Alhaidari (3 May 2004) 2008-07-11T00:29:17-00:00 2004 oscillator http://www.citeulike.org/user/LWelch/article/2985621 <i>(25 Jul 2006)</i><br /><br />Two-Body Dirac equations of constraint dynamics provide a covariant framework to investigate the problem of highly relativistic quarks in meson bound states. This formalism eliminates automatically the problems of relative time and energy, leading to a covariant three dimensional formalism with the same number of degrees of freedom as appears in the corresponding nonrelativistic problem. It provides bound state wave equations with the simplicity of the nonrelativistic Schroedinger equation. Here we begin important tests of the relativistic sixteen component wave function solutions obtained in a recent work on meson spectroscopy, extending a method developed previously for positronium decay into two photons. Preliminary to this we examine the positronium decay in the 3P_0,2 states as well as the 1S_0. The two-gamma quarkonium decays that we investigate are for the η_c, η_c^′, χ_c0, χ_c2, π^0, π_2, a_2, and f_2^′ mesons. Our results for the four charmonium states compare well with those from other quark models and show the particular importance of including all components of the wave function as well as strong and CM energy dependent potential effects on the norm and amplitude. The results for the π^0, although off the experimental rate by 15%, is much closer than the usual expectations from a potential model. We conclude that the Two-Body Dirac equations lead to wave functions which provide good descriptions of the two-gamma decay amplitude and can be used with some confidence for other purposes. Tests of Two-Body Dirac Equation Wave Functions in the Decays of Quarkonium and Positronium into Two Photons Horace Crater Cheuk-Yin Wong Peter Van Alstine (25 Jul 2006) 2008-07-10T16:53:11-00:00 2006 oscillator http://www.citeulike.org/user/LWelch/article/2985486 <i>(6 Jan 2000)</i><br /><br />We review a little-known treatment of the relativistic two-body bound-state problem - that provided by Two-Body Dirac Equations obtained from constraint dynamics. We describe some of its more important results, its relation to older formulations and to quantum field theory. We list a number of features crucial for the success of such a formulation, many of which are missing from other methods; we show how the treatment provided by Two-Body Dirac Equations encompasses each of them. Two-Body Dirac Equations for Relativistic Bound States of Quantum Field Theory Horace Crater Peter Van Alstine (6 Jan 2000) 2008-07-10T15:39:01-00:00 2000 oscillator http://www.citeulike.org/user/kristgy/article/2677725 <i>40th Annual Symposium on Frequency Control. 1986 (1986), pp. 20-21.</i> The Year When Quartz Ran Short R Adler 40th Annual Symposium on Frequency Control. 1986 (1986), pp. 20-21. 2008-04-16T11:56:16-00:00 1986 40th Annual Symposium on Frequency Control. 1986 20 21 oscillator quartz http://www.citeulike.org/user/johncumbers/article/180317 <i>Nature, Vol. 435, No. 7038., pp. 118-122.</i> A synthetic gene–metabolic oscillator Eileen Fung Wilson Wong Jason Suen Thomas Bulter Sun-Gu Lee James Liao doi:10.1038/nature03508 Nature, Vol. 435, No. 7038., pp. 118-122. 2005-05-05T02:38:45-00:00 Nature 0028-0836 435 7038 118 122 Nature Publishing Group oscillator synthetic synthetic_biology http://www.citeulike.org/user/johncumbers/article/1314072 <i>Am J Physiol Endocrinol Metab, Vol. 290, No. 4. (April 2006)</i><br /><br />Insulin is secreted in discrete insulin secretory bursts. Regulation of insulin release is accomplished almost exclusively by modulation of insulin pulse mass, whereas the insulin pulse interval remains stable at approximately 4 min. It has been reported that in vivo insulin pulses can be entrained to a pulse interval of approximately 10 min by infused glucose oscillations. If oscillations in glucose concentration play an important role in the regulation of pulsatile insulin secretion, abnormal or absent glucose oscillations, which have been described in type 2 diabetes, might contribute to the defective insulin secretion. Using perifused human islets exposed to oscillatory vs. constant glucose, we questioned 1) whether the interval of insulin pulses released by human islets is entrained to infused glucose oscillations and 2) whether the exposure of islets to oscillating vs. constant glucose confers an increased signal for insulin secretion. We report that oscillatory glucose exposure does not entrain insulin pulse frequency, but it amplifies the mass of insulin secretory bursts that coincide with glucose oscillations (P < 0.001). Dose-response analyses showed that the mode of glucose drive does not influence total insulin secretion (P = not significant). The apparent entrainment of pulsatile insulin to infused glucose oscillations in nondiabetic humans in vivo might reflect the amplification of underlying insulin secretory bursts that are detected as entrained pulses at the peripheral sampling site, but without changes in the underlying pacemaker activity. The mass, but not the frequency, of insulin secretory bursts in isolated human islets is entrained by oscillatory glucose exposure. RA Ritzel JD Veldhuis PC Butler doi:10.1152/ajpendo.00381.2005 Am J Physiol Endocrinol Metab, Vol. 290, No. 4. (April 2006) 2007-05-20T23:15:41-00:00 2006 Am J Physiol Endocrinol Metab 0193-1849 290 4 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314071 <i>J Clin Endocrinol Metab, Vol. 90, No. 11. (1 November 2005), pp. 6251-6256.</i><br /><br />Context: Insulin is secreted in a pulsatile fashion with measurable orderliness (low entropy). Normal aging and diabetes in middle-aged patients is characterized by alterations in pulsatile insulin release. Objectives: We undertook the current studies to determine whether disruptions in pulsatile insulin release also accompany diabetes in the elderly. Design: Two studies were performed. In the first study, insulin values were sampled every minute for 1 h under fasting conditions. In the second study, subjects underwent a 2-h hyperglycemic glucose clamp (glucose 5.4 mM above basal). From 60-120 min, insulin was sampled every 1 min. Secretory pulse analysis was conducted using a multiparameter deconvolution technique. Setting: The study was conducted in a general clinical research center and during outpatient visits. Patients: Volunteers were healthy young [n = 10; body mass index (BMI), 23 +/- 1 kg/m2; age, 23 +/- 1 yr] and elderly (n = 10; BMI, 24 +/- 1 kg/m2; age, 78 +/- 2 yr) volunteers and elderly patients with diabetes (n = 8; BMI, 28 +/- 1 kg/m2; age, 73 +/- 2 yr). Intervention: Five of the older patients with type 2 diabetes (BMI, 29 +/- 1 kg/m2; age, 72 +/- 2 yr) were treated with continuous sc glucagon-like peptide-1 (GLP-1) (7-36) amide infusion for 6 wk, and a second 2-h hyperglycemic clamp was performed. Main Outcome Measures: Insulin burst mass, pulsatile insulin secretion, and entropy were measured. Results: Under fasting conditions, elderly patients with diabetes had a reduction in insulin burst mass (P < 0.05) that was similar to normal elderly. During hyperglycemia, elderly patients with diabetes had an even greater impairment in insulin burst mass (P < 0.05) and basal (P < 0.05) and pulsatile insulin secretion (P < 0.05) than normal elderly. Approximate entropy, a measure of irregularity of insulin release, was increased to a greater extent in older diabetes patients than normal elderly, signifying loss of orderliness of insulin secretion (P < 0.05). In response to treatment with GLP-1, insulin burst mass (P < 0.05) and pulsatile insulin secretion (P < 0.05) improved significantly in elderly patients with diabetes. Conclusions: We conclude that alterations in pulsatile insulin release can be improved in elderly patients with diabetes by the administration of sc GLP-1. 10.1210/jc.2004-2100 Deconvolution Analysis of Rapid Insulin Pulses before and after Six Weeks of Continuous Subcutaneous Administration of Glucagon-Like Peptide-1 in Elderly Patients with Type 2 Diabetes Graydon Meneilly Johannes Veldhuis Dariush Elahi doi:10.1210/jc.2004-2100 J Clin Endocrinol Metab, Vol. 90, No. 11. (1 November 2005), pp. 6251-6256. 2007-05-20T23:15:26-00:00 2005 J Clin Endocrinol Metab 90 11 6251 6256 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314070 <i>Am J Physiol Endocrinol Metab, Vol. 282, No. 3. (March 2002)</i><br /><br />Insulin is secreted as a series of punctuated secretory bursts superimposed on variable basal insulin release. The contribution of these secretory bursts to overall insulin secretion has been estimated on the basis of peripheral vein sampling in humans to encompass > or =75% of overall insulin release. A similar contribution of the pulsatile mode of release was inferred in a canine model by use of portal vein sampling. The primary regulation of insulin secretion is through perturbation of the mass and frequency of these secretory bursts. The mode of delivery of insulin into the circulation seems important for insulin action; therefore, physiological conditions that alter the pattern of insulin release may affect insulin action through this mechanism. Transhepatic intraportal shunt in humans may provide access to portal vein samples, thus potentially improving the sensitivity of detecting and quantitating the frequency, mass, and amplitude of secretory bursts along with basal release and the regularity of these variables. To establish the insulin-secretory mechanism in nondiabetic humans by the use of portal vein sampling, we here assessed the mass, frequency, amplitude, and overall contribution of pulsatile insulin secretion by deconvolution analysis of portal vein insulin profiles. We find that, in nondiabetic humans fasted overnight, the portal vein insulin concentration oscillates at a periodicity of 4.1 +/- 0.2 min/pulse and with secretory peak amplitudes averaging 660% of basal (interpulse) release. The frequency was confirmed by spectral and autocorrelation analyses. The punctuated insulin-secretory bursts partially overlap and are responsible for the majority (70 +/- 4%) of insulin release. After ingestion of a mixed meal, the insulin release was increased through amplification of the secretory burst mass (507 +/- 104 vs. 1,343 +/- 211 pmol x l(-1) x min(-1), P < 0.001), whereas frequency (4.4 +/- 0.2 vs. 4.3 +/- 0.2, P = 0.86) and basal secretion (62 +/- 14 vs. 91 +/- 22 pmol x l(-1) x min(-1), P = 0.33) were unaffected. One subject with diabetes and cirrhosis had a similar insulin-secretory pattern, whereas a subject with insulin-dependent diabetes mellitus and minimal insulin release had preserved pulsatile release. A single subject was entrained to show agreement between entrained frequency and portal vein insulin oscillations. We conclude that insulin release in the human portal vein occurs at a mean periodicity of 4.4 +/- 0.2 min with a high signal-to-noise ratio (pulse amplitude 660% of basal). The impact of noise on the detected high frequency cannot be excluded. Human insulin release processes measured by intraportal sampling. N Pørksen T Grøfte J Greisen A Mengel C Juhl JD Veldhuis O Schmitz M Rössle H Vilstrup doi:10.1152/ajpendo.00516.2000 Am J Physiol Endocrinol Metab, Vol. 282, No. 3. (March 2002) 2007-05-20T23:15:12-00:00 2002 Am J Physiol Endocrinol Metab 0193-1849 282 3 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314069 <i>J Clin Endocrinol Metab, Vol. 87, No. 5. (1 May 2002), pp. 1965-1973.</i><br /><br />Chronic renal failure (CRF) is associated with mechanistically unexplained impaired insulin sensitivity. Erratic insulin secretory patterns typify other states of insulin resistance. We sought to investigate possible alterations of plasma insulin oscillations in CRF. We assessed high- and low-frequency insulin and glucose oscillations in 7 male CRF patients and 11 controls by multiparametric deconvolution analysis and cluster analysis, approximate entropy (ApEn) statistic, and cross-ApEn statistics. Insulin sensitivity was appraised by euglycemic hyperinsulinemic clamps. Despite impaired glucose disappearance rates in CRF, fasting and 24-h mean insulin and glucose concentrations did not differ between patients and controls. However, patients showed a 2.5-fold increase of insulin elimination half-life, reduced frequency of both rapid (6.1 +/- 0.4 vs. 7.1 +/- 0.2 h-1, P < 0.001) and slow oscillations of insulin release (0.54 +/- 0.11 vs. 0.71 +/- 0.1 h-1, P < 0.001), lack of acceleration and paradoxically more orderly slow insulin and glucose pulses after meals, and increased temporal coupling between insulin and glucose patterns (cross-ApEn: 0.58 +/- 0.13 vs. 1.37 +/- 0.23, P < 0.001). Postprandial glucose intolerance was inferable by prolonged and amplified blood glucose excursions despite exaggerated insulin bursts of almost 3-fold higher area. In summary, CRF is associated with a complex disruption of the temporal organization of insulin release, which differs from abnormalities observed to date in other states of insulin resistance. 10.1210/jc.87.5.1965 Altered Temporal Organization of Plasma Insulin Oscillations in Chronic Renal Failure Reinhard Feneberg Monika Sparber Johannes Veldhuis Otto Mehls Eberhard Ritz Franz Schaefer doi:10.1210/jc.87.5.1965 J Clin Endocrinol Metab, Vol. 87, No. 5. (1 May 2002), pp. 1965-1973. 2007-05-20T23:14:56-00:00 2002 J Clin Endocrinol Metab 87 5 1965 1973 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314068 <i>J Clin Endocrinol Metab, Vol. 88, No. 2. (1 February 2003), pp. 742-747.</i><br /><br />Insulin is secreted almost exclusively in discrete bursts, and physiological regulation is accomplished by modulation of the pulse mass. How the integrity of contiguous anatomic structures in the human pancreas (islets, splanchnic innervation, exocrine tissue, local hormones) directs the coordinated insulin secretion is not known. We posed the hypothesis that glucose stimulates insulin secretion from isolated human islets by an amplification of insulin pulse mass with no change in pulse frequency and that the glucose dose-response curve for the regulation of insulin pulse mass mirrors that recognized in vivo. Islets from five nondiabetic cadaveric donors were perifused in a recently validated perifusion system at 4 mM and subsequently at 8, 12, 16, or 24 mM glucose. The effluent was collected in 1-min intervals and used for the measurement of insulin (ELISA). Pulsatile insulin secretion was analyzed by deconvolution analysis. Total insulin secretion increased progressively (P < 0.0001). This augmentation was due to amplified pulse mass (3-fold, 24 mM vs. 4 mM glucose; P < 0.0001) with no change in pulse interval ([~]4 min). Pulsatile insulin secretion was stimulated most effectively in a physiologic concentration range of 4-8 mM. The islet insulin content was significantly correlated to the magnitude of first and second phase insulin secretion (P < 0.0001). The quantifiable orderliness of pulsatile insulin secretion rose with escalating glucose concentration (P = 0.02). In conclusion, glucose stimulates pulsatile insulin secretion from isolated human islets by amplification of insulin pulse mass without altering pulse interval. The in vitro concentration-response relationship is comparable with that observed in vivo. These data imply that transplanted human islets should be able to reproduce glucose-regulated insulin secretion as observed in the intact human pancreas. 10.1210/jc.2002-021250 Glucose Stimulates Pulsatile Insulin Secretion from Human Pancreatic Islets by Increasing Secretory Burst Mass: Dose-Response Relationships Robert Ritzel Johannes Veldhuis Peter Butler doi:10.1210/jc.2002-021250 J Clin Endocrinol Metab, Vol. 88, No. 2. (1 February 2003), pp. 742-747. 2007-05-20T23:14:44-00:00 2003 J Clin Endocrinol Metab 88 2 742 747 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314067 <i>Diabetes, Vol. 51 Suppl 1 (February 2002)</i><br /><br />Insulin is released as secretory bursts superimposed on basal release. The overall contribution of secretory bursts was recently quantified as at least 75%, and the main regulation of insulin secretion is through perturbation of the amount of insulin released and the frequency of these secretory bursts. The mode of delivery of insulin into the circulation seems important for insulin action, and therefore physiological conditions that alter the pattern of insulin release may affect insulin action through this mechanism. To assess the mechanisms by which fasting changes the amount of insulin released and the frequency, amplitude, and overall contribution of pulsatile insulin secretion, we used a validated deconvolution model to examine pulsatile insulin secretion during 10 and 58 h of fasting in seven healthy subjects. The subjects were studied for 75 min before (0-75 min) and 75 min during (115-190 min) a glucose infusion (2.5 mg.kg(-1).min(-1)). We found that the pulsatile insulin release pattern was preserved and that, at fasting, overall insulin release is adjusted to needs by a reduced amount of insulin released (10.1 +/- 1.7 vs. 16.0 +/- 3.2 pmol/l/pulse, P < 0.05) but similar frequency (6.3 +/- 0.4 vs. 6.1 +/- 0.4 min/pulse) of the insulin secretory bursts. In both states, glucose infusion caused an increase (P < 0.05) in amount (100-200%) and frequency (approximately 20%). The impact of increased glucose concentration on pulse frequency seems distinct for in vivo versus in vitro pulsatile insulin secretion and may indicate the presence of a glucose-sensitive pacemaker, which initiates the coordinated secretory bursts. Increased insulin/C-peptide ratio at long-term fasting (6.0 vs. 9.1%, P < 0.01) indicates that the changes in insulin release patterns may be accompanied by changes in hepatic insulin extraction. Effects of fasting on physiologically pulsatile insulin release in healthy humans. C Juhl T Grøfte PC Butler JD Veldhuis O Schmitz N Pørksen Diabetes, Vol. 51 Suppl 1 (February 2002) 2007-05-20T23:14:31-00:00 2002 Diabetes 0012-1797 51 Suppl 1 insulin oscillator http://www.citeulike.org/user/johncumbers/article/1314065 <i>Diabetes, Vol. 51 Suppl 1 (February 2002)</i><br /><br />Insulin concentrations oscillate at a periodicity of 5-15 min per oscillation. These oscillations are due to coordinate insulin secretory bursts, from millions of islets. The generation of common secretory bursts requires strong within-islet and within-pancreas coordination to synchronize the secretory activity from the beta-cell population. The overall contribution of this pulsatile mechanism dominates and accounts for the majority of insulin release. This review discusses the methods involved in the detection and quantification of periodicities and individual secretory bursts. The mechanism by which overall insulin secretion is regulated through changes in the pulsatile component is discussed for nerves, metabolites, hormones, and drugs. The impaired pulsatile secretion of insulin in type 2 diabetes has resulted in much focus on the impact of the insulin delivery pattern on insulin action, and improved action from oscillatory insulin exposure is demonstrated on liver, muscle, and adipose tissues. Therefore, not only is the dominant regulation of insulin through changes in secretory burst mass and amplitude, but the changes may affect insulin action. Finally, the role of impaired pulsatile release in early type 2 diabetes suggests a predictive value of studies on insulin pulsatility in the development of this disease. Pulsatile insulin secretion: detection, regulation, and role in diabetes. N Pørksen M Hollingdal C Juhl P Butler JD Veldhuis O Schmitz Diabetes, Vol. 51 Suppl 1 (February 2002) 2007-05-20T23:13:45-00:00 2002 Diabetes 0012-1797 51 Suppl 1 insulin oscillator http://www.citeulike.org/user/jkominek/article/1449902 <i>Frequency Control Symposium, 1992. 46th., Proceedings of the 1992 IEEE (1992), pp. 238-256.</i><br /><br />The performance of a rubidium oscillator disciplined to Global Positioning System (GPS) satellite time transmissions is presented together with the phase look loop technique used. The results show an offset frequency accuracy of 1.0×10^-11, while maintaining a phase accuracy of 300 ns versus universal time code (UTC). Typically, the offset frequency error was &les;2.0×10^-12. Results of analyzing recently acquired GPS data are presented. The fractional frequency stability of least squares estimates performed on the data demonstrate that one can at best expect 2.0×10^-11 frequency accuracy with an OCXO, and can expect accuracies of 2.0×10^-12 (typically) with rubidium oscillators Performance of a PID phase lock loop with Kalman filtered input data [GPS data] R Hardin M Yankowski Frequency Control Symposium, 1992. 46th., Proceedings of the 1992 IEEE (1992), pp. 238-256. 2007-07-11T20:44:23-00:00 1992 Frequency Control Symposium, 1992. 46th., Proceedings of the 1992 IEEE 238 256 kalman oscillator http://www.citeulike.org/user/jkominek/article/1449897 <i>Frequency Control, 1989., Proceedings of the 43rd Annual Symposium on (1989), pp. 16-19.</i><br /><br />The MCXO uses a novel technique to achieve temperature compensation without the use of ovens or conventional temperature-compensating components. The crystal oscillator in the MCXO, which is free to vary with temperature, operates on two modes simultaneously-the fundamental and the third overtone. Several advantages accrue because this method of temperature compensation does not resort to frequency pulling. The authors presents the details of how the MCXO operates and the details of the performance of the delivered systems The microcomputer compensated crystal oscillator (MCXO) M Bloch M Meirs J Ho Frequency Control, 1989., Proceedings of the 43rd Annual Symposium on (1989), pp. 16-19. 2007-07-11T20:42:09-00:00 1989 Frequency Control, 1989., Proceedings of the 43rd Annual Symposium on 16 19 oscillator http://www.citeulike.org/user/jkominek/article/1449895 <i>Instrumentation and Measurement, IEEE Transactions on, Vol. 50, No. 3. (2001), pp. 833-838.</i><br /><br />A new methodology of frequency syntonization using GPS carrier phase double differences is presented. The proposed scheme can achieve the traceability of frequency dissemination and obtain the very high frequency stability in the short term, as well as in the long term. The GPS receivers used in our system were elaborately modified in order to estimate the frequency offset of the remote low-cost oven-controlled crystal oscillator clock with respect to the primary cesium atomic clock in real time by performing the double differences on the GPS carrier phase observables. The fuzzy controller and the proportional-derivative controller were employed to implement the controllers of our system, respectively. Through the D/A converter, the remote clock was then steered to synchronize with the primary clock. For averaging times of one day under the configuration of about a 30-m baseline, our experimental results show that the accuracy of the remote clock can be improved from about 3×10^-9 to about 3×10^-14, and the stability of the remote clock can be improved from about 3×10^-10 to about 2×10^-14. Moreover, the 30-m baseline tests with the common high-performance cesium clock revealed that our system has a frequency stability of about 2×10 ^-16 for averaging times of one day Frequency syntonization using GPS carrier phase measurements Kun-Yuan Tu Fan-Ren Chang Chia-Shu Liao Li-Sheng Wang Instrumentation and Measurement, IEEE Transactions on, Vol. 50, No. 3. (2001), pp. 833-838. 2007-07-11T20:39:43-00:00 2001 Instrumentation and Measurement, IEEE Transactions on 50 3 833 838 oscillator http://www.citeulike.org/user/jkominek/article/1449894 <i>Solid-State Circuits, IEEE Journal of, Vol. 35, No. 10. (2000), pp. 1502-1506.</i><br /><br />The base frequency of oscillators used in the Global System for Mobile Communication (GSM) network or Global Positioning System (GPS) receiver applications needs to be very stable with respect to temperature and supply-voltage variations. One approach to obtain extremely good frequency stability is the use of oven-stabilized crystal oscillators. With this kind of oscillator, a frequency stability versus temperature of a few ppb versus the standard temperature range can be achieved. In this paper, a digitally compensated crystal oscillator is described. The system provides a frequency stability of (Δf)/f<1.5 ppm for a temperature range of -40°C to 90°C compared to about ±20 ppm for a noncompensated crystal. The core of the system is an application-specified integrated circuit (ASIC) fabricated in a standard 0.8-μm CMOS process. The power consumption for the oscillator running at 13 MHz is 100 mW. The final device equipped with the ASIC, crystal blank, and a few external components fits into a 14×9×3 mm³ package A digitally temperature-compensated crystal oscillator R Achenbach M Feuerstack-Raible F Hiller M Keller K Meier H Rudolph R Saur-Brosch Solid-State Circuits, IEEE Journal of, Vol. 35, No. 10. (2000), pp. 1502-1506. 2007-07-11T20:37:20-00:00 2000 Solid-State Circuits, IEEE Journal of 35 10 1502 1506 oscillator http://www.citeulike.org/user/jkominek/article/1449892 <i>Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European, Vol. 1 (1999), pp. 251-254 vol.1.</i><br /><br />The paper presents the application results of different types of optimal and quasi optimal Kalman filters looked after the oven controlled crystal oscillator (OCXO) with reference timing signals of GPS Motorola Oncore UT+ Timing Receiver. Some simple algorithms have been studied for different definitions of filter coefficients, thereupon we showed that optimal, and quasioptimal ones have the similar asymptotic levels with t→∞ but different output noises and transfer times of covariance function Kalman filtering of a frequency instability based on Motorola Oncore UT GPS timing signals OE Rudnev Yu Shmaliy EG Sokolinskiy Shmaliy OI Kharchenko Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European, Vol. 1 (1999), pp. 251-254 vol.1. 2007-07-11T20:36:16-00:00 1999 Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European 1 251 254 vol.1 kalman oscillator http://www.citeulike.org/user/jkominek/article/1449861 <i>Frequency Control Symposium and Exposition, 2004. Proceedings of the 2004 IEEE International (2004), pp. 509-517.</i><br /><br />An algorithm has been implemented in a CDMA cellular radio system to enable a 5 fold reduction in the stability requirement of the base station time reference oscillator. The algorithm adaptively models the frequency drift characteristics of the base station time reference OCXO whilst locked to a satellite time reference signal. If the satellite time reference is lost, the OCXO model is used to provide time correction of the base station reference oscillator for a holdover period of up to 24 hours during which repair or reacquisition of the satellite time reference signal is conducted. The novel algorithm uses two parallel Kalman filters to model adaptively the temperature and aging dependent frequency stability of the OCXO. The algorithm extracts the stability dependencies of the OCXO with respect to the noisy satellite time reference. Adaptive training of the Kalman filters occurs until satellite visibility is lost, and is re-initiated after the satellite time reference has been reacquired; thus, the algorithm is cognizant of changes in the OCXO frequency stability characteristics over its lifetime. In holdover, the Kalman filters operate as predictive state machines which generate a correction signal for the base station OCXO time reference based on the trained coefficients of the adaptive models. The correction algorithm has been trialed in a CDMA base station network and demonstrated to maintain the 10 MHz timing module reference oscillator to within 1.5 /spl mu/s of the CDMA system time over a holdover period of 24 hr, well within the 3GPP2 CDMA standard cumulative time error specification of 10 /spl mu/s over an 8 hr holdover period. Simulations indicate the feasibility of the algorithm to compensate for a further 10 fold reduction in reference oscillator stability whilst still meeting the 8 hr holdover specification. Adaptive OCXO drift correction algorithm CWT Nicholls GC Carleton Frequency Control Symposium and Exposition, 2004. Proceedings of the 2004 IEEE International (2004), pp. 509-517. 2007-07-11T20:23:45-00:00 2004 Frequency Control Symposium and Exposition, 2004. Proceedings of the 2004 IEEE International 509 517 kalman oscillator http://www.citeulike.org/user/jkominek/article/1405181 <i>Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International (1995), pp. 259-265.</i><br /><br />During the summer of 1994, the Advanced Research Projects Agency and the United States Coast Guard Academy collected extensive radionavigation data in the New York City area. The purpose was to determine the feasibility of using existing radionavigation systems for tracking applications in an urban environment. The data includes the accuracy and availability of the Global Positioning System (GPS) and LORAN, a comparison of electric field (whip) and magnetic field (loop) antennas at both LORAN and Differential GPS frequencies, and the increased availability of both GPS and LORAN by adding a precise clock input to the receivers. The data was collected among the narrow streets and tall buildings in the Wall Street area, among the tall buildings but wider streets of Third Avenue, in the relatively more open streets and smaller buildings of the Bronx, in the vicinity of the large metallic structure of the George Washington Bridge, and under the cover of foliage along the New Jersey side of the Hudson River. Of particular interest in this paper is the study of how the availability of radionavigation fixes can be substantially enhanced in these urban areas by the integration of a precise clock with LORAN and GPS navigation information. More specifically, a clock allows a geographic fix to be obtained from as few as two Time of Arrival (TOA) measurements. In the case of LORAN in NYC, Seneca and Nantucket are 10-12 dB stronger than Carolina Beach, hence a precise clock provides a significantly higher fix availability since only two stations (plus the clock) are used in obtaining the two TOA fix. Similar improvements in fix availability are achieved in the integrated LORAN/GPS and the GPS modes by using a precise clock. Preliminary results of implementing a two satellite fix using an external Cesium reference and a GPS Builder Kit manufactured by GEC Plessey are presented. A secondary advantage of using a precise clock occurs in receiver reacquisition after signal loss in the urban environment. Quite simply, in the case of GPS, one can tolerate longer outages without having the GPS receiver reenter the “search” mode, since a precise oscillator can stay within one chip (one usec) for a longer period of time (like durations corresponding to brief signal outages due to shielding). Should the oscillator drift beyond one chip, acquisition is still quicker since one need only search over a handful of Doppler bins when using a precise clock. By having two GPS Builder Kits side by side, each looking at the same signals, with one referenced to a Cesium and one referenced to its own clock, we examine acquisition and reacquisition improvements in a very controlled way for performance comparisons GPS/LORAN in an urban environment-oscillator stability considerations B Peterson RJ Hartnett G Ottman L Miller Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International (1995), pp. 259-265. 2007-06-22T20:36:48-00:00 1995 Frequency Control Symposium, 1995. 49th., Proceedings of the 1995 IEEE International 259 265 clock gps loran oscillator http://www.citeulike.org/user/ibschwartz/article/1059759 <i>Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 74, No. 3. (2006)</i><br /><br />Synchronization of stochastic phase-coupled oscillators is known to occur but difficult to characterize because sufficiently complete analytic work is not yet within our reach, and thorough numerical description usually defies all resources. We present a discrete model that is sufficiently simple to be characterized in meaningful detail. In the mean-field limit, the model exhibits a supercritical Hopf bifurcation and global oscillatory behavior as coupling crosses a critical value. When coupling between units is strictly local, the model undergoes a continuous phase transition that we characterize numerically using finite-size scaling analysis. In particular, we explicitly rule out multistability and show that the onset of global synchrony is marked by signatures of the XY universality class. Our numerical results cover dimensions d=2, 3, 4, and 5 and lead to the appropriate XY classical exponents and , a lower critical dimension dlc=2, and an upper critical dimension duc=4. Critical behavior and synchronization of discrete stochastic phase-coupled oscillators Kevin Wood C Van den Broeck R Kawai Katja Lindenberg doi:10.1103/PhysRevE.74.031113 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics), Vol. 74, No. 3. (2006) 2007-01-22T13:18:36-00:00 2006 Physical Review E (Statistical, Nonlinear, and Soft Matter Physics) 74 3 APS fluctuations oscillator stochastic synchronization http://www.citeulike.org/user/ibschwartz/article/1030125 <i>Physical Review Letters, Vol. 97, No. 26. (2006)</i><br /><br />We propose a technique to couple the position operator of a nanomechanical resonator to a SQUID device by modulating its magnetic flux bias. By tuning the magnetic field properly, either linear or quadratic couplings can be realized, with a discretely adjustable coupling strength. This provides a way to realize coherent nonlinear effects in a nanomechanical resonator by coupling it to a Josephson quantum circuit. As an example, we show how squeezing of the nanomechanical resonator state can be realized with this technique. We also propose a simple method to measure the uncertainty in the position of the nanomechanical resonator without quantum state tomography. Nonlinear Coupling of Nanomechanical Resonators to Josephson Quantum Circuits Xingxiang Zhou Ari Mizel doi:10.1103/PhysRevLett.97.267201 Physical Review Letters, Vol. 97, No. 26. (2006) 2007-01-08T13:36:35-00:00 2006 Physical Review Letters 97 26 APS coupled jj nanomechanics oscillator http://www.citeulike.org/user/ibschwartz/article/1047052 <i>Chaos: An Interdisciplinary Journal of Nonlinear Science, Vol. 15, No. 2. (2005)</i><br /><br />We study the stochastic dynamics of an ensemble of N globally coupled excitable elements. Each element is modeled by a FitzHugh–Nagumo oscillator and is disturbed by independent Gaussian noise. In simulations of the Langevin dynamics we characterize the collective behavior of the ensemble in terms of its mean field and show that with the increase of noise the mean field displays a transition from a steady equilibrium to global oscillations and then, for sufficiently large noise, back to another equilibrium. In the course of this transition diverse regimes of collective dynamics ranging from periodic subthreshold oscillations to large-amplitude oscillations and chaos are observed. In order to understand the details and mechanisms of these noise-induced dynamics we consider the thermodynamic limit N of the ensemble, and derive the cumulant expansion describing temporal evolution of the mean field fluctuations. In Gaussian approximation this allows us to perform the bifurcation analysis; its results are in good qualitative agreement with dynamical scenarios observed in the stochastic simulations of large ensembles. ©2005 American Institute of Physics Noise induced complexity: From subthreshold oscillations to spiking in coupled excitable systems MA Zaks X Sailer Schimansky Geier AB Neiman doi:10.1063/1.1886386 Chaos: An Interdisciplinary Journal of Nonlinear Science, Vol. 15, No. 2. (2005) 2007-01-17T20:48:05-00:00 2005 Chaos: An Interdisciplinary Journal of Nonlinear Science 15 2 AIP fluctuations noise oscillator http://www.citeulike.org/user/ibschwartz/article/1158476 <i>Physical Review Letters, Vol. 98, No. 6. (2007)</i><br /><br />We describe a transition from fully synchronous periodic oscillations to partially synchronous quasiperiodic dynamics in ensembles of identical oscillators with all-to-all coupling that nonlinearly depends on the generalized order parameters. We present an analytically solvable model that predicts a regime where the mean field does not entrain individual oscillators, but has a frequency incommensurate to theirs. The self-organized onset of quasiperiodicity is illustrated with Landau-Stuart oscillators and a Josephson junction array with a nonlinear coupling. Self-Organized Quasiperiodicity in Oscillator Ensembles with Global Nonlinear Coupling Michael Rosenblum Arkady Pikovsky doi:10.1103/PhysRevLett.98.064101 Physical Review Letters, Vol. 98, No. 6. (2007) 2007-03-13T18:55:58-00:00 2007 Physical Review Letters 98 6 APS coupled jj oscillator http://www.citeulike.org/user/ibschwartz/article/1245999 <i>Science, Vol. 316, No. 5821. (6 April 2007), pp. 95-99.</i><br /><br />We report measurements of synchronization in two nanomechanical beam oscillators coupled by a mechanical element. We charted multiple regions of frequency entrainment or synchronization by their corresponding Arnold's tongue diagrams as the oscillator was driven at subharmonic and rational commensurate frequencies. Demonstration of multiple synchronized regions could be fundamentally important to neurocomputing with mechanical oscillator networks and nanomechanical signal processing for microwave communication. 10.1126/science.1137307 Synchronized Oscillation in Coupled Nanomechanical Oscillators Seung-Bo Shim Matthias Imboden Pritiraj Mohanty doi:10.1126/science.1137307 Science, Vol. 316, No. 5821. (6 April 2007), pp. 95-99. 2007-04-23T19:35:30-00:00 2007 Science 316 5821 95 99 coupled nanomechanics oscillator http://www.citeulike.org/user/ibschwartz/article/1211369 <i>Physical Review Letters, Vol. 98, No. 5. (2007)</i><br /><br />We present an approach for the description of fluctuations that are due to finite system size induced correlations in the Kuramoto model of coupled oscillators. We construct a hierarchy for the moments of the density of oscillators that is analogous to the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy in the kinetic theory of plasmas and gases. To calculate the lowest order system size effect, we truncate this hierarchy at second order and solve the resulting closed equations for the two-oscillator correlation function around the incoherent state. We use this correlation function to compute the fluctuations of the order parameter, including the effect of transients, and compare this computation with numerical simulations. Kinetic Theory of Coupled Oscillators Eric Hildebrand Michael Buice Carson Chow doi:10.1103/PhysRevLett.98.054101 Physical Review Letters, Vol. 98, No. 5. (2007) 2007-04-05T17:08:16-00:00 2007 Physical Review Letters 98 5 APS coupled oscillator http://www.citeulike.org/user/homer12345/article/2190328 <i>Instrumentation and Measurement, IEEE Transactions on, Vol. 47, No. 1. (1998), pp. 293-298.</i><br /><br />A signal conditioning circuit for resistive sensors is presented. It is based on a relaxation oscillator in which both the frequency and the duty-cycle of the square-wave output signal simultaneously carry information from a pair of different sensors. The output frequency is linearly related to the resistive unbalance of a Wheatstone bridge, while the duty-cycle is independently controlled by a second sensor. The latter can be a thermoresistor used for thermal compensation of the primary sensor. The design, analysis, and experimental characterization of the circuit and its application to a thick-film pressure sensor are reported. A method for compensating the accuracy degradation caused by the finite switching delays is illustrated, and results on its experimental validation are given Oscillator-based signal conditioning with improved linearity for resistive sensors V Ferrari C Ghidini D Marioli A Taroni doi:10.1109/19.728837 Instrumentation and Measurement, IEEE Transactions on, Vol. 47, No. 1. (1998), pp. 293-298. 2008-01-03T00:30:04-00:00 1998 Instrumentation and Measurement, IEEE Transactions on 47 1 293 298 1998 oscillator resistor wheatstone http://www.citeulike.org/user/homer123/article/155250 <i>Sensors, 2002. Proceedings of IEEE, Vol. 2 (2002), pp. 1436-1439 vol.2.</i><br /><br />A novel front-end circuit for capacitive sensors with switched-capacitor (SC) circuits is presented. In this circuit charge is transferred to an input integrator circuit in a controlled way to prevent overload of the input amplifier. Application of this technique extends the linear range for large input signals. SC interface for capacitive measurements with extended linear range V Iordanov G Meijer S Nihtianov Sensors, 2002. Proceedings of IEEE, Vol. 2 (2002), pp. 1436-1439 vol.2. 2005-04-08T01:07:13-00:00 2002 Sensors, 2002. Proceedings of IEEE 2 1436 1439 vol.2 circuit oscillator scap