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1

Gravitational Fixed Points from Perturbation Theory

The fixed point structure of the renormalization flow in higher derivative gravity is investigated in terms of the background covariant effective action using an operator cutoff that keeps track of powerlike divergences. Spectral positivity of the gauge fixed Hessian can be satisfied upon expansion in the asymptotically free higher derivative coupling. At one-loop order in this coupling strictly positive fixed points are found for the dimensionless Newton constant g{sub N} and the cosmological constant lambda, which are determined solely by the coefficients of the powerlike divergences. The renormalization flow is asymptotically safe with respect to this fixed point and settles on a lambda(g{sub N}) trajectory after O(10) units of the renormalization mass scale to accuracy 10{sup -7}.

Niedermaier, Max R. [CNRS, Laboratoire de Mathematiques et Physique Theorique, 37000 Tours (France)

2009-09-04

2

Logistic Map Fixed Points Model

NSDL National Science Digital Library

The Logistic Map Fixed Points Model finds periodic trajectories of the logistic map such that n iterations of the map starting with an initial value x return to that value. The key idea for this model is that for values of the logistic map control parameter r in the chaotic regime, there are periodic but unstable trajectories. This property of the chaotic regime means that if we choose the value of the seed x0 to be precisely equal to a point on an unstable trajectory with period n, the subsequent trajectory will have this period. However, if we choose a value of x0 that differs ever so slightly from this special value, the trajectory will not be periodic. This model shows how to find these special values of x0. The Logistic Map Fixed Points Model was created using the Easy Java Simulations (EJS) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_chaos_LogisticMapFixedPoints.jar file will run the program if Java is installed.

Christian, Wolfgang

2012-01-29

3

Stability and Asymptotic Fixed Point Theory.

National Technical Information Service (NTIS)

An asymptotic fixed point theorem is developed as a generalization of the Schauder fixed point theorem which states: if S is a closed convex subset of a Banach space X, every continuous compact mapping of S into itself has a fixed point. When it is diffic...

G. S. Jones

1965-01-01

4

Fixed point theorems and dissipative processes.

NASA Technical Reports Server (NTRS)

Operators of the type considered by Hale et al. (1972) are used to show that under certain conditions there is a fixed point in a dissipative map within a Banach space. The conditions required for the existence of this fixed point are discussed in detail. Several fixed point theorems are formulated and proved.

Hale, J. K.; Lopes, O.

1973-01-01

5

Fixed point theorems and dissipative processes

NASA Technical Reports Server (NTRS)

The deficiencies of the theories that characterize the maximal compact invariant set of T as asymptotically stable, and that some iterate of T has a fixed point are discussed. It is shown that this fixed point condition is always satisfied for condensing and local dissipative T. Applications are given to a class of neutral functional differential equations.

Hale, J. K.; Lopes, O.

1972-01-01

6

Higgs Boson Spectrum from Infrared Fixed Point.

National Technical Information Service (NTIS)

The fixed point structure of the renormalization group equations for the scalar quartic couplings in the one and two-doublet models is studied. Masses of the physical Higgs bosons can be determined by the infrared fixed points of the quartic coupling cons...

C. N. Leung

1985-01-01

7

Explicit Fixed Points for Interpretability Logic.

National Technical Information Service (NTIS)

Basic theorems of provability logic are addressed. The problem of uniqueness and explicit definability of fixed points for interpretability logic is considered. Uniqueness is shown as an immediate corollary of a theorem of Smorynski, so the study is devot...

D. Dejongh A. Visser

1989-01-01

8

Characterizations of fixed points of quantum operations

Let {phi}{sub A} be a general quantum operation. An operator B is said to be a fixed point of {phi}{sub A}, if {phi}{sub A}(B)=B. In this note, we shall show conditions under which B, a fixed point {phi}{sub A}, implies that B is compatible with the operation element of {phi}{sub A}. In particular, we offer an extension of the generalized Lueders theorem.

Li Yuan [College of Mathematics and Information Science, Shaanxi Normal University, Xi'an, 710062 (China)

2011-05-15

9

A fixed point theorem for discontinuous functions

Any function from a non-empty polytope into itself that is locally gross direction preserving is shown to have the fixed point property. Brouwer's fixed point theorem for continuous functions is a special case. We discuss the application of the result in the area of non-cooperative game theory. © 2007 Elsevier B.V. All rights reserved. MSC: 47H10; 65K10; 91A10

P. Jean-jacques Herings; Gerard Van Der Laan; Dolf Talman; Zaifu Yang

2008-01-01

10

Fixed action patterns and neural Darwinism

Summary The stereotopy of the “Fixed Action Pattern” of classical ethology is customarily attributed to “hard wiring”. We submit that this explanation is akin to the 17th century use of the homunculus to explain development. We propose extendingEdelman's notions of neural Darwinism to explain the emergence of species-characteristic (“innate”) motor patterns.

Peter H. Klopfer; Norman Budnitz

1990-01-01

11

ASIC For Complex Fixed-Point Arithmetic

NASA Technical Reports Server (NTRS)

Application-specific integrated circuit (ASIC) performs 24-bit, fixed-point arithmetic operations on arrays of complex-valued input data. High-performance, wide-band arithmetic logic unit (ALU) designed for use in computing fast Fourier transforms (FFTs) and for performing ditigal filtering functions. Other applications include general computations involved in analysis of spectra and digital signal processing.

Petilli, Stephen G.; Grimm, Michael J.; Olson, Erlend M.

1995-01-01

12

Fixed Point Theorems for Paracompact Convex Sets.

National Technical Information Service (NTIS)

In the present paper a few fixed point theorems are given for upper hemi-continuous mappings from a paracompact convex set to its embracing space, a real, locally convex, Hausdorff topological vector space. 9 references. (ERA citation 12:042704)

Jiang Jiahe

1986-01-01

13

The fixed point technique for electrophysical identification

NASA Astrophysics Data System (ADS)

The shape of an inaccessible boundary between two different media is identified by applying a dc field. The electric potential is described by Fredholm's integral equation of the first kind. Numerical processing leads to a system of nonlinear and ill-conditioned algebraic equations. Their solution causes numerical problems. A new algorithm based on the Brouwer's fixed point theorem is proposed as a solution. Le champ de courant continu identifie la forme d'une frontière inaccessible au milieu de deux matériaux avec des caractéristiques électrophysiques différentes. La distribution de potentiel électrique est décrite par des équations intégrales de Fredholm. Le traitement numérique des équations conduit à un système d'équations algébriques mal-conditionnées difficile à résoudre numériquement. Dans notre article, pour définir une solution, nous avons appliqué le théorème de Brouwer (théorème de point fixe).

Peterson, W.

1998-01-01

14

Distributed asynchronous computation of fixed points

We present an algorithmic model for distributed computation of fixed points whereby several processors participate simultaneously\\u000a in the calculations while exchanging information via communication links. We place essentially no assumptions on the ordering\\u000a of computation and communication between processors thereby allowing for completely uncoordinated execution. We provide a\\u000a general convergence theorem for algorithms of this type, and demonstrate its applicability

Dimitri P. Bertsekas

1983-01-01

15

Infrared fixed point in quantum Einstein gravity

NASA Astrophysics Data System (ADS)

We performed the renormalization group analysis of the quantum Einstein gravity in the deep infrared regime for different types of extensions of the model. It is shown that an attractive infrared point exists in the broken symmetric phase of the model. It is also shown that due to the Gaussian fixed point the IR critical exponent ? of the correlation length is 1/2. However, there exists a certain extension of the model which gives finite correlation length in the broken symmetric phase. It typically appears in case of models possessing a first order phase transitions as is demonstrated on the example of the scalar field theory with a Coleman-Weinberg potential.

Nagy, S.; Krizsan, J.; Sailer, K.

2012-07-01

16

The Split Common Fixed Point Problem for Directed Operators

We propose the split common fixed point problem that requires to find a common fixed point of a family of operators in one space whose image under a linear transformation is a common fixed point of another family of operators in the image space. We formulate and analyze a parallel algorithm for solving this split common fixed point problem for

Yair Censor; Alexander Segal

2008-01-01

17

New SMU Gallium Fixed-Point Cells

NASA Astrophysics Data System (ADS)

In the framework of the European research project EURAMET 732, the Slovak Institute of Metrology (SMU) built three primary gallium fixed-point cells of different designs. The cells are designed for the calibration of the long-stem SPRT. In regard to the procedure commonly used at SMU when realizing the gallium point, the cells are designed for use in a stirred liquid bath. This article provides information about the cell designs, materials used, method of filling, and results of the performed experiments. The experiments were focused on the study of the cells' metrological characteristics, some effects that could influence the melting-point temperature and the effect of the melted metal fraction on the immersion profile. New cells were compared with the SMU reference gallium cell.

Ranostaj, Juraj; ?uriš, Stanislav; Knorová, Renáta; Kaskötö, Mariana; Vysko?ilová, Irena

2011-08-01

18

47 CFR 101.137 - Interconnection of private operational fixed point-to-point microwave stations.

Code of Federal Regulations, 2013 CFR

... Interconnection of private operational fixed point-to-point microwave stations... SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Technical Standards... Interconnection of private operational fixed point-to-point microwave...

2013-10-01

19

Effects of nondenumerable fixed points in finite dynamical systems

NASA Astrophysics Data System (ADS)

The motion of a spinning soccer ball brings forth the possible existence of a whole class of finite dynamical systems where there may be a nondenumerably infinite number of fixed points. They defy the very traditional meaning of the fixed point that a point on the fixed point in the phase space should remain there forever, for, a fixed point can evolve as well! Under such considerations one can argue that a free-kicked soccer ball should be nonchaotic.

Chakraborty, Sagar; Bhattacharjee, J. K.

2008-03-01

20

Holographic non-Fermi-liquid fixed points.

Techniques arising from string theory can be used to study assemblies of strongly interacting fermions. Via this 'holographic duality', various strongly coupled many-body systems are solved using an auxiliary theory of gravity. Simple holographic realizations of finite density exhibit single-particle spectral functions with sharp Fermi surfaces, of a form distinct from those of the Landau theory. The self-energy is given by a correlation function in an infrared (IR) fixed-point theory that is represented by a two-dimensional anti de Sitter space (AdS(2)) region in the dual gravitational description. Here, we describe in detail the gravity calculation of this IR correlation function. PMID:21422019

Faulkner, Tom; Iqbal, Nabil; Liu, Hong; McGreevy, John; Vegh, David

2011-04-28

21

The Split Common Fixed Point Problem for Directed Operators

We propose the split common fixed point problem that requires to find a common fixed point of a family of operators in one space whose image under a linear transformation is a common fixed point of another family of operators in the image space. We formulate and analyze a parallel algorithm for solving this split common fixed point problem for the class of directed operators and note how it unifies and generalizes previously discussed problems and algorithms.

Censor, Yair; Segal, Alexander

2010-01-01

22

Linear fixed point function for solving system of polynomial equations

NASA Astrophysics Data System (ADS)

We compare fixed-point auxiliary homotopy function with a proposed linear fixed-point auxiliary homotopy function to determine which method has greater applicability and greater accuracy. We test the methods on systems of polynomial equations by using Newton-Homotopy Continuation method. The results obtained indicate the superior applicability and accuracy of the proposed linear fixed-point (LFP) auxiliary homotopy function.

Nor, Hafizudin Mohamad; Md. Ismail, Ahmad Izani; Majid, Ahmad Abdul

2014-06-01

23

Some fixed point results for multi-valued cyclic mappings

NASA Astrophysics Data System (ADS)

This paper investigates the fixed points and best proximity points of multivalued cyclic self-mappings in metric spaces under a generalized contractive condition involving Hausdorff distances. Some previous results for cyclic self-mappings or for multivalued self-mappings in metric fixed point theory are extended to cyclic multivalued self-mappings.

De la Sen, M.; Singh, S. L.; Gordji, M. E.

2013-09-01

24

A note on fixed point sets in CAT(0) spaces

We show that the fixed point set of a quasi-nonexpansive selfmap of a nonempty convex subset of a CAT(0) space is always closed, convex and contractible. Moreover, we give a construction of a continuous selfmap of a CAT(0) space whose fixed point set is prescribed.

P. Chaoha; A. Phon-On

2006-01-01

25

Fixed Point Data Type Modeling for High Level Synthesis

A methodology to automatically convert fixed point data type representations into integer data types for high level synthesis is presented in this work. Our method converts all major C operations using fixed point data types into integer data types, models quantization and overflow modes, type conversion and casting. The conversion rule for each operation is described in detail as well

Benjamin Carrión Schäfer; Yusuke Iguchi; Wataru Takahashi; Shingo Nagatani; Kazutoshi Wakabayashi

2010-01-01

26

SEQUENCES OF CONTRACTIONS AND CONVERGENCE OF FIXED POINTS

Stability of fixed points of contraction mappings has been studied by Bonsall (cf. (2)) and Nadler (cf. (4)). These authors consider a sequence (Tn) of maps defined on a metric space (X, d) into itself and study the convergence of the sequence of fixed points for uniform or pointwise convergence of (Tn), under contraction assumptions of the maps. We will

Luc Barbet; Khadra Nachi

27

Maximal neutrino mixing from an attractive infrared fixed point

In the Standard Model (and MSSM), renormalization effects on neutrino mixing are generally very small and the attractive fixed points are at vanishing neutrino mixing. However for multi-Higgs extensions of the Standard Model, renormalization effects on neutrino mixing can be large and nontrivial fixed points are possible. Here we examine a simple two-Higgs model. For two flavors, maximal mixing is

James Pantaleone; T. K. Kuo; Guo-Hong Wu

2001-01-01

28

Did you mean: fixed point stability nonlinear Integra-differential equation variable delay Ilene soualhia assen dodged paper accepted publishing soon fixed point stability fixed point stability paper accepted Ilene soualhia ardjouni ?

29

Oxides in metal fixed points of the ITS-90

NASA Astrophysics Data System (ADS)

In the range between 0 °C and 961 °C, the International Temperature Scale of 1990 (ITS-90) depends to a great extent on the freezing points of the pure metals gallium, indium, tin, zinc, aluminium and silver. An up-to-date realization of these fixed points is based on cells containing metals of ultra-high purity (6N or better) and should include a correction for the influence of relevant impurities. Still, chemical analyses of the fixed-point material can show large amounts of oxygen, which had to be neglected so far, because of the lack of detailed knowledge about it, presuming it could be removed from the cell by applying a vacuum (less than 1 Pa) for a few hours. In this paper we discuss an equilibrium of several forms of oxygen in a fixed-point cell, gaseous in the cell's atmosphere, dissolved in the fixed-point metal and as oxide in a separate (solid) phase. We will conclude that in many fixed points most of the oxygen is not dissolved in the metal, but bound in oxides of the fixed-point metal as well as oxides of some impurities. To demonstrate the impact that the precipitation of impurity oxides has on thermometry, two indium fixed-point cells were doped with magnesium and chromium, which leave the fixed-point temperature unchanged. Further evidence is drawn from earlier work. All these results support the presumed existence of (at least one) persistent separate oxide phase in the fixed points of indium, tin, zinc and aluminium, which renders them eutectic or peritectic points and is a more likely reason why the oxygen content of a cell does not influence the fixed-point temperature. To complement these studies, thermodynamic calculations show how to treat the equilibrium in the cell quantitatively. Using available chemical data, a list is provided that indicates for each fixed-point metal (including the other metal fixed points of the ITS-90: mercury, gold, copper) the impurities that probably build oxides. Due to the agreement of the calculated values with the presented experimental results, we suggest excluding those impurities from the correction of a fixed-point temperature (e.g. the SIE method), unless there is strong evidence of their dissolution.

Fahr, Martin; Rudtsch, Steffen

2009-10-01

30

Symplectic fixed points and holomorphic spheres

LetP be a symplectic manifold whose symplectic form, integrated over the spheres inP, is proportional to its first Chern class. On the loop space ofP, we consider the variational theory of the symplectic action function perturbed by a Hamiltonian term. In particular, we associate to each isolated invariant set of its gradient flow an Abelian group with a cyclic grading.

Andreas Floer

1989-01-01

31

A new compact fixed-point blackbody furnace

NASA Astrophysics Data System (ADS)

More and more NMIs are realizing their primary scale themselves with fixed-point blackbodies as their reference standard. However, commercially available fixed-point blackbody furnaces of sufficient quality are not always easy to obtain. CHINO Corp. and NMIJ, AIST jointly developed a new compact fixed-point blackbody furnace. The new furnace has such features as 1) improved temperature uniformity when compared to previous products, enabling better plateau quality, 2) adoption of the hybrid fixed-point cell structure with internal insulation to improve robustness and thereby to extend lifetime, 3) easily ejectable and replaceable heater unit and fixed-point cell design, leading to reduced maintenance cost, 4) interchangeability among multiple fixed points from In to Cu points. The replaceable cell feature facilitates long term maintenance of the scale through management of a group of fixed-point cells of the same type. The compact furnace is easily transportable and therefore can also function as a traveling standard for disseminating the radiation temperature scale, and for maintaining the scale at the secondary level and industrial calibration laboratories. It is expected that the furnace will play a key role of the traveling standard in the anticipated APMP supplementary comparison of the radiation thermometry scale.

Hiraka, K.; Yamada, Y.; Ishii, J.; Oikawa, H.; Shimizu, T.; Kadoya, S.; Kobayashi, T.

2013-09-01

32

A new compact fixed-point blackbody furnace

More and more NMIs are realizing their primary scale themselves with fixed-point blackbodies as their reference standard. However, commercially available fixed-point blackbody furnaces of sufficient quality are not always easy to obtain. CHINO Corp. and NMIJ, AIST jointly developed a new compact fixed-point blackbody furnace. The new furnace has such features as 1) improved temperature uniformity when compared to previous products, enabling better plateau quality, 2) adoption of the hybrid fixed-point cell structure with internal insulation to improve robustness and thereby to extend lifetime, 3) easily ejectable and replaceable heater unit and fixed-point cell design, leading to reduced maintenance cost, 4) interchangeability among multiple fixed points from In to Cu points. The replaceable cell feature facilitates long term maintenance of the scale through management of a group of fixed-point cells of the same type. The compact furnace is easily transportable and therefore can also function as a traveling standard for disseminating the radiation temperature scale, and for maintaining the scale at the secondary level and industrial calibration laboratories. It is expected that the furnace will play a key role of the traveling standard in the anticipated APMP supplementary comparison of the radiation thermometry scale.

Hiraka, K.; Oikawa, H.; Shimizu, T.; Kadoya, S.; Kobayashi, T. [CHINO CORPORATION, Itabashi, Tokyo (Japan)] [CHINO CORPORATION, Itabashi, Tokyo (Japan); Yamada, Y.; Ishii, J. [National Metrology Institute of Japan, AIST, Tsukuba, Ibaraki (Japan)] [National Metrology Institute of Japan, AIST, Tsukuba, Ibaraki (Japan)

2013-09-11

33

KAM-tori near an analytic elliptic fixed point

NASA Astrophysics Data System (ADS)

We study the accumulation of an elliptic fixed point of a real analytic Hamiltonian by quasi-periodic invariant tori. We show that a fixed point with Diophantine frequency vector ? 0 is always accumulated by invariant complex analytic KAM-tori. Indeed, the following alternative holds: If the Birkhoff normal form of the Hamiltonian at the invariant point satisfies a Rüssmann transversality condition, the fixed point is accumulated by real analytic KAM-tori which cover positive Lebesgue measure in the phase space (in this part it suffices to assume that ? 0 has rationally independent coordinates). If the Birkhoff normal form is degenerate, there exists an analytic subvariety of complex dimension at least d + 1 passing through 0 that is foliated by complex analytic KAM-tori with frequency ? 0. This is an extension of previous results obtained in [1] to the case of an elliptic fixed point.

Eliasson, L. Hakan; Fayad, Bassam; Krikorian, Raphaël

2013-11-01

34

Capture of a point mass by two fixed centers.

NASA Astrophysics Data System (ADS)

The possibility of a point mass being captured in the problem of two fixed centers is considered. A solution in terms of Weierstrass functions is obtained and analyzed. Relations are introduced which the initial coordinates and velocity of the point must satisfy in order for capture to be possible. Here the point moves in a plane that passes through the two fixed centers and the initial position of the point mass along a spiral that winds about the line segment connecting the two centers. Conditions necessary for the mass point to coincide with one of the centers are investigated.

Vinnikov, E. L.; Gerasimov, I. A.; Sumarokov, S. I.

1994-03-01

35

Introduction. Kakutani's fixed point theorem (3)1 states that in Euclidean «-space a closed point to (nonvoid) convex set map of a convex compact set into itself has a fixed point. Kakutani showed that this implied the minimax theorem for finite games. The object of this note is to point out that Kakutani's theorem may be extended to convex linear topological

I. L. Glicksberg

36

Realization at IMGC of the ITS90 Fixed Points from the Argon Triple Point Upwards

The actual status of IMGC facilities for the realization of the ITS-90 fixed points is illustrated, including new apparatus for the realization of the triple point of argon and of the freezing points of gold and copper. For each fixed point very long phase transitions are obtained, and several thermometers can be calibrated on each plateau. The present apparatus is

P. Marcarino; P. P. M. Steur; R. Dematteis

2003-01-01

37

Fixing the quantum three-point function

NASA Astrophysics Data System (ADS)

We propose a new method for the computation of quantum three-point functions for operators in (2) sectors of = 4 super Yang-Mills theory. The method is based on the existence of a unitary transformation relating inhomogeneous and long-range spin chains. This transformation can be traced back to a combination of boost operators and an inhomogeneous version of Baxter's corner transfer matrix. We reproduce the existing results for the one-loop structure constants in a simplified form and indicate how to use the method at higher loop orders. Then we evaluate the one-loop structure constants in the quasiclassical limit and compare them with the recent strong coupling computation.

Jiang, Yunfeng; Kostov, Ivan; Loebbert, Florian; Serban, Didina

2014-04-01

38

2-Cone Banach spaces and fixed point theorem

NASA Astrophysics Data System (ADS)

The present article deals with 2-cone normed spaces, 2-cone Banach spaces. Also, some results expressing under what conditions a self-mapping T of 2-cone Banach space (X, ||.,.||c) has a unique fixed point are given.

Sahiner, Ahmet; Yigit, Tuba

2012-09-01

39

Exponential lower bounds for finding Brouwer fixed points

The Brouwer fixed point theorem has become a major tool for modeling economic systems during the 20th century. It was intractable to use the theorem in a computational manner until 1965 when Scarf provided the first practical algorithm for finding a fixed point of a Brouwer map. Scarf's work left open the question of worst-case complexity, although he hypothesized that his algorithm had ''typical'' behavior of polynomial time in the number of variables of the problem. Here we show that any algorithm for fixed points based on function evaluation (which includes all general purpose fixed-point algorithms) must in the worst case take a number of steps which is exponential both in the number of digits of accuracy and in the number of variables. 12 refs., 4 figs.

Hirsch, M.D.; Vavasis, S.

1987-01-01

40

Proof mining in metric fixed point theory and ergodic theory

In this survey we present some recent applications of proof mining to the fixed point theory of (asymptotically) nonexpansive mappings and to the metastability (in the sense of Terence Tao) of ergodic averages in uniformly convex Banach spaces.

Laurentiu Leustean

2009-01-01

41

Twining Characters, Orbit Lie Algebras, and Fixed Point Resolution.

National Technical Information Service (NTIS)

The authors describe the resolution of field identification fixed points in coset conformal field theories in terms of representation spaces of the coset chiral algebra. A necessary ingredient from the representation theory of Kac-Moody algebras is the re...

J. Fuchs B. Schellekens C. Schweigert

1995-01-01

42

Fixed Points of Quantum Gravity and the Renormalisation Group

We review the asymptotic safety scenario for quantum gravity and the role and\\u000aimplications of an underlying ultraviolet fixed point. We discuss\\u000arenormalisation group techniques employed in the fixed point search, analyse\\u000athe main picture at the example of the Einstein-Hilbert theory, and provide an\\u000aoverview of the key results in four and higher dimensions. We also compare\\u000afindings with

Daniel F. Litim

2008-01-01

43

Quark and lepton masses from renormalization-group fixed points

The renormalization-group equations describing the evolution of fermion--Higgs-boson Yukawa coupling constants down from M\\/sub X\\/ in a grand unified theory possess fixed points which may lead to universal predictions for fermion masses independent of symmetry considerations at M\\/sub X\\/. Our analysis predicts roughly-equal240 GeV for the fixed-point t-quark mass. Alternatively, a sufficiently heavy fourth SU(5) generation cannot be ruled out

Christopher Hill

1981-01-01

44

Stability and Fixed Points of Point Dissipative Systems.

National Technical Information Service (NTIS)

The result requires the stronger assumption of compact dissipative. The principle result of this paper will be to get similar results under the weaker assumption of point dissipative. Need exists to add additional hypotheses on the space and the operator ...

P. Massatt

1979-01-01

45

Further Findings of Impurity Precipitation in Metal Fixed Points

NASA Astrophysics Data System (ADS)

Impurities are believed to be one of the major issues in realizing the metal fixed-point temperatures of the ITS-90 with a low degree of uncertainty. This has raised interest in the individual effects of impurities on the phase-transition temperature of fixed-point metals. Surprisingly, impurities that do not affect a fixed-point temperature have been found experimentally. A possible explanation for this behavior is the formation of insoluble oxides of the added impurities consuming oxygen already present in the fixed-point cell (mostly as an oxide of the fixed-point metal). This is supported by several recent publications. However, all the results could be coincidental. This article presents more convincing proof for the formation of insoluble compounds born from impurities dissolved in the fixed-point metal. Based on refined doping experiments and using impurities that have not been investigated before, both the impurities' dissolution and the precipitation could be observed as an initial decrease (or increase) of the fixed-point temperature followed by a gradual return to its original value. The selected impurities (gallium and zinc in indium) were found to dissolve within a few days and precipitate out within no more than two weeks. The behavior of iron in indium was investigated as well, but the results are not conclusive. Finally, another series of doping experiments indicates that sulfur does not dissolve in indium in significant amounts, but forms insoluble compounds (probably sulfides) when added to the metal. This supports the general assumption that metal-non-metal compounds might be present in the cell without being noticed.

Fahr, M.; Rudtsch, S.; Aulich, A.

2011-12-01

46

Stray thermal influences in zinc fixed-point cells

The influence of thermal effects is a major uncertainty contribution to the calibration of Standard Platinum Resistance Thermometers (SPRTs) in fixed-point cells. Axial heat losses strongly depend on the fixed-point temperature, constructional details of cells and SPRTs and the resulting heat transfer between cell, thermometer, furnace and environment. At the zinc point contributions by heat conduction and thermal radiation must be considered. Although the measurement of temperature gradients in the re-entrant well of a fixed-point cell provides very important information about the influence of axial heat losses, further investigations are required for a reliable estimate of the resulting uncertainty contribution. It is shown that specific modifications of a zinc fixed-point cell, following generally accepted principles, may result in systematic deviations of the measured fixed-point temperatures larger than typically stated in the uncertainty budget of National Metrology Institutes (NMIs). The underlying heat transport processes are investigated and the consequences for the construction of zinc cells are discussed.

Rudtsch, S.; Aulich, A.; Monte, C. [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany)] [Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin (Germany)

2013-09-11

47

On R-symmetric Fixed Points and Superconformality

An important unanswered question in quantum field theory is to understand precisely under which conditions scale invariance implies invariance under the full conformal group. While the general answer in two dimensions has been known for over 20 years, a precise nonperturbative relation between scale and conformal invariance in higher dimensions has been lacking. In this note, we specialize to four dimensions and give a full quantum mechanical proof that certain unitary R-symmetric fixed points are necessarily superconformal. Among other consequences, this result implies that the infrared fixed points of N=1 supersymmetric quantum chromodynamics are superconformal.

Antoniadis, Ignatios; Buican, Matthew [Department of Physics, CERN Theory Division, CH-1211 Geneva 23 (Switzerland)

2011-05-15

48

Disordered horizons: holography of randomly disordered fixed points.

We deform conformal field theories with classical gravity duals by marginally relevant random disorder. We show that the disorder generates a flow to IR fixed points with a finite amount of disorder. The randomly disordered fixed points are characterized by a dynamical critical exponent z>1 that we obtain both analytically (via resummed perturbation theory) and numerically (via a full simulation of the disorder). The IR dynamical critical exponent increases with the magnitude of disorder, probably tending to z?? in the limit of infinite disorder. PMID:24972193

Hartnoll, Sean A; Santos, Jorge E

2014-06-13

49

Disordered Horizons: Holography of Randomly Disordered Fixed Points

NASA Astrophysics Data System (ADS)

We deform conformal field theories with classical gravity duals by marginally relevant random disorder. We show that the disorder generates a flow to IR fixed points with a finite amount of disorder. The randomly disordered fixed points are characterized by a dynamical critical exponent z >1 that we obtain both analytically (via resummed perturbation theory) and numerically (via a full simulation of the disorder). The IR dynamical critical exponent increases with the magnitude of disorder, probably tending to z?? in the limit of infinite disorder.

Hartnoll, Sean A.; Santos, Jorge E.

2014-06-01

50

Measurement of thermodynamic temperature of high temperature fixed points

The paper is devoted to VNIIOFI's measurements of thermodynamic temperature of the high temperature fixed points Co-C, Pt-C and Re-C within the scope of the international project coordinated by the Consultative Committee for Thermometry working group 5 'Radiation Thermometry'. The melting temperatures of the fixed points were measured by a radiance mode radiation thermometer calibrated against a filter radiometer with known irradiance spectral responsivity via a high temperature black body. This paper describes the facility used for the measurements, the results and estimated uncertainties.

Gavrilov, V. R.; Khlevnoy, B. B.; Otryaskin, D. A.; Grigorieva, I. A.; Samoylov, M. L.; Sapritsky, V. I. [All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), 46 Ozernaya St., Moscow 119361 (Russian Federation)] [All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), 46 Ozernaya St., Moscow 119361 (Russian Federation)

2013-09-11

51

Weierstrass weights of fixed points of an involution

NASA Astrophysics Data System (ADS)

Let X be a curve with an involution T which fixes r points. We show that the Weierstrass weight of a fixed point is at least (r[minus sign]2)(r[minus sign]4)/8. Our proof is independent of the recent result of Torres.We consider the case where X=Fn, the nth Fermat curve, and T is any of the involutions of Fn. We find that our bound is equal to the actual weight in all known cases (n[less-than-or-eq, slant]7) and compute then n=8 case to demonstrate that the equality continues to hold.

Towse, Christopher

1997-11-01

52

Fixed Points and Stable Subgroups of Algebraic Group Automorphisms.

National Technical Information Service (NTIS)

The paper presents a study of the fixed point sets and stable subgroups of automorphisms of a connected algebraic linear group over an algebraically closed field of arbitrary characteristic. Many of the results were proved at characteristic O by Borel-Mos...

D. J. Winter

1966-01-01

53

Fixed Point Theorems with Applications to Economics and Game Theory

One of the problems in economics that economists have devoted a considerable amount of attention in prevalent years has been to ensure consistency in the models they employ. Assuming markets to be generally in some state of equilibrium, it is asked under what circumstances such equilibrium is possible. The fundamental mathematical tools used to address this concern are fixed point

Kim C. Border

1985-01-01

54

Fixed Point Problems for Linear Transformations on Pythagorean Triples

ERIC Educational Resources Information Center

In this article, an attempt is made to find all linear transformations that map a standard Pythagorean triple (a Pythagorean triple [x y z][superscript T] with y being even) into a standard Pythagorean triple, which have [3 4 5][superscript T] as their fixed point. All such transformations form a monoid S* under matrix product. It is found that S*…

Zhan, M.-Q.; Tong, J.-C.; Braza, P.

2006-01-01

55

Matrix model fixed point of noncommutative ?4 theory

NASA Astrophysics Data System (ADS)

In this article, we exhibit explicitly the matrix model (?=?) fixed point of ?4 theory on noncommutative spacetime with only two noncommuting directions, using the Wilson renormalization group recursion formula and the 1/N expansion of the zero-dimensional reduction, and then calculate the mass critical exponent ? and the anomalous dimension ? in various dimensions.

Ydri, Badis; Ahmim, Rachid

2013-11-01

56

Fast Fixed-Point Algorithm for Independent Component Analysis.

National Technical Information Service (NTIS)

We introduce a novel fast algorithm for Independent Component Analysis, which can be used for blind source separation and blind deconvolution. It is shown how a neural network learning rule can be transformed into a fixed-point iteration, which provides a...

A. Hyvaerinen E. Oja

1996-01-01

57

Common Fixed Points Versus Invariant Approximation In Nonconvex Sets

The aim of the present paper is to establish an existence result on common fixed point of best approximation without using the starshapedness condition of the domain. As a consequence, our result improves and extends the corresponding results of Dhage (4) and Mukherjee and Som (10).

Hemant Kumar Nashine; Mohammad Saeed Khan

2009-01-01

58

Fixed Points of Difference Operator of Meromorphic Functions

Let f be a transcendental meromorphic function of order less than one. The authors prove that the exact difference ?f =(z+1) - f (z) has infinitely many fixed points, if a ? ? and ? are Borel exceptional values (or Nevanlinna deficiency values) of f. These results extend the related results obtained by Chen and Shon.

Wu, Zhaojun; Xu, Hongyan

2014-01-01

59

A Hybrid Common Fixed Point Theorem under Certain Recent Properties

We prove a common fixed point theorem for a hybrid pair of occasionally coincidentally idempotent mappings via common limit range property. Our result improves some results from the existing literature, especially the ones contained in Sintunavarat and Kumam (2009). Some illustrative and interesting examples to highlight the realized improvements are also furnished.

Imdad, Mohammad

2014-01-01

60

Fixed point theorems for generalized contractions in ordered metric spaces

NASA Astrophysics Data System (ADS)

The purpose of this paper is to present some fixed point results for self-generalized contractions in ordered metric spaces. Our results generalize and extend some recent results of A.C.M. Ran, M.C. Reurings [A.C.M. Ran, MEC. Reurings, A fixed point theorem in partially ordered sets and some applications to matrix equations, Proc. Amer. Math. Soc. 132 (2004) 1435-1443], J.J. Nieto, R. Rodríguez-López [J.J. Nieto, R. Rodríguez-López, Contractive mapping theorems in partially ordered sets and applications to ordinary differential equations, Order 22 (2005) 223-239; J.J. Nieto, R. Rodríguez-López, Existence and uniqueness of fixed points in partially ordered sets and applications to ordinary differential equations, Acta Math. Sin. (Engl. Ser.) 23 (2007) 2205-2212], J.J. Nieto, R.L. Pouso, R. Rodríguez-López [J.J. Nieto, R.L. Pouso, R. Rodríguez-López, Fixed point theorem theorems in ordered abstract sets, Proc. Amer. Math. Soc. 135 (2007) 2505-2517], A. Petrusel, I.A. Rus [A. Petrusel, I.A. Rus, Fixed point theorems in ordered L-spaces, Proc. Amer. Math. Soc. 134 (2006) 411-418] and R.P. Agarwal, M.A. El-Gebeily, D. O'Regan [R.P. Agarwal, M.A. El-Gebeily, D. O'Regan, Generalized contractions in partially ordered metric spaces, Appl. Anal., in press]. As applications, existence and uniqueness results for Fredholm and Volterra type integral equations are given.

O'Regan, Donal; Petrusel, Adrian

2008-05-01

61

Renormalization-group flows and fixed points in Yukawa theories

NASA Astrophysics Data System (ADS)

We study renormalization-group flows in Yukawa theories with massless fermions, including determination of fixed points and curves that separate regions of different flow behavior. We assess the reliability of perturbative calculations for various values of Yukawa coupling y and quartic scalar coupling ? by comparing the properties of flows obtained with the beta functions of these couplings calculated to different orders in the loop expansion. The results provide a determination of the region in y and ? where calculations up to two loops can yield reasonably reliable results. In the regime of weak couplings where the perturbative calculations are most reliable, we find that the theories have no nontrivial fixed points, and the flow is toward a free theory in the infrared.

Mølgaard, Esben; Shrock, Robert

2014-05-01

62

The computational core and fixed point organization in Boolean networks

NASA Astrophysics Data System (ADS)

In this paper, we analyse large random Boolean networks in terms of a constraint satisfaction problem. We first develop an algorithmic scheme which allows us to prune simple logical cascades and underdetermined variables, returning thereby the computational core of the network. Second, we apply the cavity method to analyse the number and organization of fixed points. We find in particular a phase transition between an easy and a complex regulatory phase, the latter being characterized by the existence of an exponential number of macroscopically separated fixed point clusters. The different techniques developed are reinterpreted as algorithms for the analysis of single Boolean networks, and they are applied in the analysis of and in silico experiments on the gene regulatory networks of baker's yeast (Saccharomyces cerevisiae) and the segment-polarity genes of the fruitfly Drosophila melanogaster.

Correale, L.; Leone, M.; Pagnani, A.; Weigt, M.; Zecchina, R.

2006-03-01

63

Fixed-point methods for asemiconductor quantum dot model

This paper presents various fixed-point methods for computing the ground state energy and its associated wave function of a semiconductor quantum dot model. The discretization of the three-dimensional SchrSdinger equation leads to a large-scale cubic matrix polynomial eigenvalue problem for which the desired eigenvalue is embedded in the interior of the spectrum. The cubic problem is reformulated in several forms

Tsung-Min Hwang; Wen-Wei Lin; Jinn-Liang Liu; Weichung Wang

2004-01-01

64

Fixed point structure of quenched, planar quantum electrodynamics

Gauge theories exhibiting a hierarchy of fermion mass scales may contain a pseudo-Nambu-Boldstone boson of spontaneously broken scale invariance. The relation between scale and chiral symmetry breaking is studied analytically in quenched, planar quantum electrodynamics in four dimensions. The model possesses a novel nonperturbative ultraviolet fixed point governing its strong coupling phase which requires the mixing of four fermion operators. 12 refs.

Love, S.T.

1986-07-01

65

The split common fixed-point problem for demicontractive mappings

Based on the very recent work by Censor and Segal (2009 J. Convex Anal. 16 587-600) and inspired by Xu (2006 Inverse Problems 22 2021-34) and Yang (2004 Inverse Problems 20 1261-6), we investigate an algorithm for solving the split common fixed-point problem for the class of demicontractive operators in a Hilbert space. Our results improve and\\/or develop previously discussed

A. Moudafi

2010-01-01

66

The = 1 superconformal index for class fixed points

NASA Astrophysics Data System (ADS)

We investigate the superconformal index of four-dimensional superconformal field theories that arise on coincident M5 branes wrapping a holomorphic curve in a local Calabi-Yau three-fold. The structure of the index is very similar to that which appears in the special case preserving = 2 supersymmetry. We first compute the index for the fixed points that admit a known four-dimensional ultraviolet description and prove infrared equivalence at the level of the index for all such constructions. These results suggest a formulation of the index as a two-dimensional topological quantum field theory that generalizes the one that computes the = 2 index. The TQFT structure leads to an expression for the index of a much larger family of = 1 class S fixed points in terms of the index of the = 2 theories. Calculations of simple quantities with the index suggests a connection between these families of fixed points and the mathematics of SU(2) Yang-Mills theory on the wrapped curve.

Beem, Christopher; Gadde, Abhijit

2014-04-01

67

Fixed point indices of iterated smooth maps in arbitrary dimension

NASA Astrophysics Data System (ADS)

Let f be a smooth self-map of R, when m is an arbitrary natural number. We give a complete description of possible sequences of indices of iterations of f at an isolated fixed point, answering in affirmative the Chow, Mallet-Paret and Yorke conjecture posed in [S.N. Chow, J. Mallet-Parret, J.A. Yorke, A periodic point index which is a bifurcation invariant, in: Geometric Dynamics, Rio de Janeiro, 1981, in: Lecture Notes in Math., vol. 1007, Springer, Berlin, 1983, pp. 109-131].

Graff, Grzegorz; Jezierski, Jerzy; Nowak-Przygodzki, Piotr

68

Assigning thermodynamic temperatures to high-temperature fixed-points

NASA Astrophysics Data System (ADS)

Workpackage five of the High Temperature Fixed-Point research programme will determine the thermodynamic temperature for the equilibrium melting transition of the pure eutectic systems of Re-C, Pt-C and Co-C and, in addition, the freezing point of Cu. Measurements of four different cells of each type will be made by nine participating laboratories. This paper describes how the melt sensitivity to the rate of the previous freeze, furnace effects and cell impurities will be accounted for and how the results will be combined allowing for all existing correlations.

Woolliams, E. R.; Bloembergen, P.; Machin, G.

2013-09-01

69

Triple Point of E-Deuterium as an Accurate Thermometric Fixed Point.

National Technical Information Service (NTIS)

The triple point of deuterium (18.7 deg K) is the only possibility for excluding vapor pressure measurements in the definition of a temperature scale based on fixed points between 13.81 and 24.562 deg K. This paper reports an investigation made at the Ist...

F. Pavese G. T. McConville

1986-01-01

70

A comparison of roundoff noise in floating point and fixed point digital filter realizations

A statistical model for roundoff noise in floating point digital filters, proposed by Kaneko and Liu, is tested experimentally for first- and second-order digital filters. Good agreement between theory and experiment is obtained. The model is used to specify a comparison between floating point and fixed point digital filter realizations on the basis of their output noise-to-signal ratio, and curves

C. Weinstein; A. V. Oppenheim

1969-01-01

71

Quantization and fixed points of non-integrable Weyl theory

NASA Astrophysics Data System (ADS)

We consider a simple but generic model of gravity where Weyl invariance is realized thanks to the presence of a gauge field for dilatations. We quantize the theory by suitably defining renormalization group flows that describe the integration of successive momentum shells, in such a way that Weyl invariance is maintained in the flow. When the gauge fields are massless the theory has, in addition to Weyl invariance, an abelian gauge symmetry. According to the definition of the cutoff, the flow can break or preserve this extended symmetry. We discuss the fixed points of these flows.

Pagani, C.; Percacci, R.

2014-06-01

72

Quantized vortex reconnection: Fixed points and initial conditions

NASA Astrophysics Data System (ADS)

Quantized vortices are phase singularities in complex fields. In superfluids, they appear as mobile interacting defects that may cross and reconnect by exchanging tails. Reconnection is a topology-changing event that allows vortex tangles to decay; it is a defining signature of quantum turbulence. We report a family of fixed points (i.e., stationary solutions), including planar forms, that capture reconnection in the Gross-Pitaevskii model in contrast to previous suggestions of pyramidal structures. These are obtained using a well known, systematic method for generating low-energy relaxed initial conditions for Gross-Pitaevskii simulations.

Meichle, David P.; Rorai, Cecilia; Fisher, Michael E.; Lathrop, D. P.

2012-07-01

73

Fate of CPN-1 fixed points with q monopoles.

We present an extensive quantum Monte Carlo study of the Néel to valence-bond solid (VBS) phase transition on rectangular- and honeycomb-lattice SU(N) antiferromagnets in sign-problem-free models. We find that in contrast to the honeycomb lattice and previously studied square-lattice systems, on the rectangular lattice for small N, a first-order Néel-VBS transition is realized. On increasing N?4, we observe that the transition becomes continuous and with the same universal exponents as found on the honeycomb and square lattices (studied here for N=5, 7, 10), providing strong support for a deconfined quantum critical point. Combining our new results with previous numerical and analytical studies, we present a general phase diagram of the stability of CPN-1 fixed points with q monopoles. PMID:24116811

Block, Matthew S; Melko, Roger G; Kaul, Ribhu K

2013-09-27

74

Fate of CPN-1 Fixed Points with q Monopoles

NASA Astrophysics Data System (ADS)

We present an extensive quantum Monte Carlo study of the Néel to valence-bond solid (VBS) phase transition on rectangular- and honeycomb-lattice SU(N) antiferromagnets in sign-problem-free models. We find that in contrast to the honeycomb lattice and previously studied square-lattice systems, on the rectangular lattice for small N, a first-order Néel-VBS transition is realized. On increasing N?4, we observe that the transition becomes continuous and with the same universal exponents as found on the honeycomb and square lattices (studied here for N=5, 7, 10), providing strong support for a deconfined quantum critical point. Combining our new results with previous numerical and analytical studies, we present a general phase diagram of the stability of CPN-1 fixed points with q monopoles.

Block, Matthew S.; Melko, Roger G.; Kaul, Ribhu K.

2013-09-01

75

Twelve years of high temperature fixed point research: A review

NASA Astrophysics Data System (ADS)

A review of research into high temperature fixed points (HTFPs), since their inception at NMIJ in 1999 until 2011 is given. HTFPs discussed in this paper are those whose transition temperatures are above the freezing point of copper and based on eutectic/peritectic alloys. The paper will begin with an historical overview; including a description of the different types of modern HTFPs. The evolution of construction methods of HTFPs will be elaborated. The performance of the current generation of HTFPs will be compared to that of earlier ones. Current uses of HTFPs will be described. Finally an overview of some remaining research issues will be given including assignment of definitive thermodynamic temperatures and inclusion into the developing mise en pratique for the definition of the kelvin.

Machin, G.

2013-09-01

76

Fixed-point auto-landing algorithm for UAV based on point tracking

NASA Astrophysics Data System (ADS)

A new automatic fixed-point landing algorithm for UAV using the instantaneous speed obtained by image sensors and computer vision method is proposed. In the proposed scheme, once the specified land pad for landing is captured, the UAV will switch from auto-seeking mode to landing mode. In the landing mode, the feature point of the prospective zone is extracted and then being tracked. The noise in the motion parameter introduced by the feature point mismatching is reduced by fast iterative least square algorithm, and the accurate instantaneous speed of UAV is obtained. The simulation results show that the proposed algorithm efficiently improve the accuracy of the estimation of instantaneous velocity for the fixed-point landing system of UAV.

Shao, Zhiyu; Nie, Zhengang; Feng, Yuan; Feng, Shunshan

2009-12-01

77

Multi-Valued Modal Fixed Point Logics for Model Checking

NASA Astrophysics Data System (ADS)

In this paper, I will show how multi-valued logics are used for model checking. Model checking is an automatic technique to analyze correctness of hardware and software systems. A model checker is based on a temporal logic or a modal fixed point logic. That is to say, a system to be checked is formalized as a Kripke model, a property to be satisfied by the system is formalized as a temporal formula or a modal formula, and the model checker checks that the Kripke model satisfies the formula. Although most existing model checkers are based on 2-valued logics, recently new attempts have been made to extend the underlying logics of model checkers to multi-valued logics. I will summarize these new results.

Nishizawa, Koki

78

A Fixed-Point Iteration Method with Quadratic Convergence

The fixed-point iteration algorithm is turned into a quadratically convergent scheme for a system of nonlinear equations. Most of the usual methods for obtaining the roots of a system of nonlinear equations rely on expanding the equation system about the roots in a Taylor series, and neglecting the higher order terms. Rearrangement of the resulting truncated system then results in the usual Newton-Raphson and Halley type approximations. In this paper the introduction of unit root functions avoids the direct expansion of the nonlinear system about the root, and relies, instead, on approximations which enable the unit root functions to considerably widen the radius of convergence of the iteration method. Methods for obtaining higher order rates of convergence and larger radii of convergence are discussed.

Walker, Kevin P. [Engineering Science Software, Inc.; Sham, Sam [ORNL

2012-01-01

79

Comparisons of some NIST fixed-point cells with similar cells of other standards laboratories

In this paper we present results of international comparisons of fixed-point cells of some of the defining fixed-point materials of the International Temperature Scale of 1990. These comparisons involved cells from seven national laboratories, although in some cases only one type of fixed-point material was compared. Except for silver cells, the agreement among cells of the same defining fixed-point material

B. W. Mangum; E. R. Pfeiffer; G. F. Strouse; J. Valencia-Rodriguez; J. H. Lin; T. I. Yeh; P. Marcarino; R. Dematteis; Y. Liu; Q. Zhao; A. T. Ince; F. Çakiroglu; H. G. Nubbemeyer; H.-J. Jung

1996-01-01

80

New insights from a fixed point analysis of single cell IEEE 802.11 WLANs

We study a fixed point formalisation of the well known analysis of Bianchi. We provide a significant simplification and generalisation of the analysis. In this more general framework, the fixed point solution and per- formance measures resulting from it are studied. Unique- ness of the fixed point is established. Simple and general throughput formulas are provided. It is shown that

Anurag Kumar; Eitan Altman; Daniele Miorandi; Munish Goyall

2005-01-01

81

A methodology and design environment for DSP ASIC fixed point refinement

Complex signal processing algorithms are specified in floating point precision. When their hardware implemen- tation requires fixed point precision, type refinement is needed. The paper presents a methodology and design en- vironment for this quantization process. The method uses independent strategies for fixing MSB and LSB weights of fixed point signals. It enables short de- sign cycles by combining the

Radim Cmar; Luc Rijnders; Patrick Schaumont; Serge Vernalde; Ivo Bolsens

1999-01-01

82

This work performs an analysis of basic optical properties of zoom lenses with a fixed distance between object and image points and a fixed position of the image-space focal point. Formulas for the calculation of paraxial parameters of such optical systems are derived and the calculation is presented on examples. PMID:24977815

Miks, Antonin; Novak, Jiri

2014-06-30

83

Fixed-Point Optimization Utility for C and C Based Digital Signal Processing Programs

Fixed-point optimization utility software is devel- oped that can aid scaling and wordlength determination of digital signal processing algorithms written in C or C. This utility consists of two programs: the range estimator and the fixed-point simulator . The former estimates the ranges of floating- point variables for purposes of automatic scaling, and the latter translates floating-point programs into fixed-point

Seehyun Kim; Ki-Il Kum; Wonyong Sung

1998-01-01

84

Fixed-point optimization utility for C and C++ based digital signal processing programs

Fixed-point optimization utility software is developed that can aid scaling and wordlength determination of digital signal processing algorithms written in C or C++. This utility consists of two programs: the range estimator and the fixed-point simulator. The former estimates the ranges of floating-point variables for purposes of automatic scaling, and the latter translates floating-point programs into fixed-point equivalents to evaluate

Seehyun Kim; Ki-Il Kum; Wonyong Sung

1998-01-01

85

Phase diagram and fixed-point structure of two-dimensional N=1 Wess-Zumino models

We study the phases and fixed-point structure of two-dimensional supersymmetric Wess-Zumino models with one supercharge. Our work is based on the functional renormalization group (RG) formulated in terms of a manifestly off-shell supersymmetric flow equation for the effective action. Within the derivative expansion, we solve the flow of the superpotential also including the anomalous dimension of the superfield. The models exhibit a surprisingly rich fixed-point structure with a discrete number of fixed-point superpotentials. Each fixed-point superpotential is characterized by its number of nodes and by the number of RG-relevant directions. In limiting cases, we find periodic superpotentials and potentials which confine the fields to a compact target space. The maximally IR-attractive fixed point has one relevant direction, the tuning of which distinguishes between supersymmetric and broken phases. For the Wess-Zumino model defined near the Gaussian fixed point, we determine the phase diagram and compute the corresponding ground-state masses.

Synatschke, Franziska; Gies, Holger; Wipf, Andreas [Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universitaet Jena, Max-Wien-Platz 1, D-07743 Jena (Germany)

2009-10-15

86

NASA Astrophysics Data System (ADS)

We prove a common fixed point theorem of Gregus type for four mappings satisfying a generalized contractive condition in metric spaces using the concept of weak compatibility which generalizes theorems of [I. Altun, D. Turkoglu, B.E. Rhoades, Fixed points of weakly compatible mappings satisfying a general contractive condition of integral type, Fixed Point Theory Appl. 2007 (2007), article ID 17301; A. Djoudi, L. Nisse, Gregus type fixed points for weakly compatible mappings, Bull. Belg. Math. Soc. 10 (2003) 369-378; A. Djoudi, A. Aliouche, Common fixed point theorems of Gregus type for weakly compatible mappings satisfying contractive conditions of integral type, J. Math. Anal. Appl. 329 (1) (2007) 31-45; P. Vijayaraju, B.E. Rhoades, R. Mohanraj, A fixed point theorem for a pair of maps satisfying a general contractive condition of integral type, Int. J. Math. Math. Sci. 15 (2005) 2359-2364; X. Zhang, Common fixed point theorems for some new generalized contractive type mappings, J. Math. Anal. Appl. 333 (2) (2007) 780-786]. We prove also a common fixed point theorem which generalizes Theorem 3.5 of [H.KE Pathak, M.S. Khan, T. Rakesh, A common fixed point theorem and its application to nonlinear integral equations, Comput. Math. Appl. 53 (2007) 961-971] and common fixed point theorems of Gregus type using a strict generalized contractive condition, a property (E.A) and a common property (E.A).

Aliouche, A.

2008-05-01

87

NASA Astrophysics Data System (ADS)

The Fixed point Open Ocean Observatory network (FixO3) seeks to integrate the 23 European open ocean fixed point observatories and to improve access to these key installations for the broader community. These will provide multidisciplinary observations in all parts of the oceans from the air-sea interface to the deep seafloor. Coordinated by the National Oceanography Centre, UK, FixO3 builds on the significant advances achieved through the previous Europe-funded FP7 programmes EuroSITES, ESONET and CARBOOCEAN. Started in September 2013 with a budget of 7 Million Euros over 4 years the project has 29 partners drawn from academia, research institutions and SME's. In addition 12 international experts from a wide range of disciplines comprise an Advisory Board. On behalf of the FixO3 Consortium, we present the programme that will be achieved through the activities of 12 Work Packages: 1. Coordination activities to integrate and harmonise the current procedures and processes. Strong links will be fostered with the wider community across academia, industry, policy and the general public through outreach, knowledge exchange and training. 2. Support actions to offer a) free access to observatory infrastructures to those who do not have such access, and b) free and open data services and products. 3. Joint research activities to innovate and enhance the current capability for multidisciplinary in situ ocean observation. Support actions include Transnational Access (TNA) to FixO3 infrastructure, meaning that European organizations can apply to free-of-charge access to the observatories for research and testing in two international calls during the project lifetime. The first call for TNA opens in summer 2014. More information can be found on FixO3 website (www.fixo3.eu/). Open ocean observation is currently a high priority for European marine and maritime activities. FixO3 will provide important data on environmental products and services to address the Marine Strategy Framework Directive and in support of the European Integrated Maritime Policy. The FixO3 network will provide free and open access to in situ fixed point data of the highest quality. It will provide a strong integrated framework of open ocean facilities in the Atlantic from the Arctic to the Antarctic and throughout the Mediterranean, enabling an integrated, regional and multidisciplinary approach to understand natural and anthropogenic change in the ocean.

Lampitt, Richard; Cristini, Luisa

2014-05-01

88

Small Fixed-Point Cells for Use in Dry Well Block Calibrators.

National Technical Information Service (NTIS)

As part of a research project for the Combined Calibration Group (CCG) of the U.S. Armed Forces, three rugged fixed-point cells were developed for use in dry well block calibrators (DWBCs). The small fixed-point cells of the water triple point (0.01 DGC),...

G. F. Strouse

2008-01-01

89

Some Extensions of Discrete Fixed Point Theorems and Their Applications to the Game Theory

NASA Astrophysics Data System (ADS)

As is well-known in the game theory, fixed point theorems are useful to show the existence of Nash equilibrium. Since they are mathematical tools in continuous variables, it is expected that discrete fixed point theorems also useful to guarantee the existence of pure-strategy Nash equilibrium. In this talk, we review three types of discrete fixed point theorems, give some extensions, and apply them to non-cooperative games.

Kawasaki, Hidefumi

2009-09-01

90

Gauge invariant and gauge fixed actions for various higher-spin fields from string field theory

NASA Astrophysics Data System (ADS)

We propose a systematic procedure for extracting gauge invariant and gauge fixed actions for various higher-spin gauge field theories from covariant bosonic open string field theory. By identifying minimal gauge invariant part for the original free string field theory action, we explicitly construct a class of covariantly gauge fixed actions with BRST and anti-BRST invariance. By expanding the actions with respect to the level N of string states, the actions for various massive fields including higher-spin fields are systematically obtained. As illustrating examples, we explicitly investigate the level N?3 part and obtain the consistent actions for massive graviton field, massive 3rd rank symmetric tensor field, or anti-symmetric field. We also investigate the tensionless limit of the actions and explicitly derive the gauge invariant and gauge fixed actions for general rank n symmetric and anti-symmetric tensor fields.

Asano, Masako

2013-03-01

91

Adaptive noise canceller (ANC) has been used to improve signal to noise ratio (SNR) of somsatosensory evoked potential (SEP). In order to efficiently apply the ANC in hardware system, fixed-point algorithm based ANC can achieve fast, cost-efficient construction, and low-power consumption in FPGA design. However, it is still questionable whether the SNR improvement performance by fixed-point algorithm is as good as that by floating-point algorithm. This study is to compare the outputs of ANC by floating-point and fixed-point algorithm ANC when it was applied to SEP signals. The selection of step-size parameter (micro) was found different in fixed-point algorithm from floating-point algorithm. In this simulation study, the outputs of fixed-point ANC showed higher distortion from real SEP signals than that of floating-point ANC. However, the difference would be decreased with increasing micro value. In the optimal selection of micro, fixed-point ANC can get as good results as floating-point algorithm. PMID:18002694

Shen, Chongfei; Liu, Hongtao; Xie, Xb; Luk, Keith Dk; Hu, Yong

2007-01-01

92

NASA Astrophysics Data System (ADS)

We determine the limit distributions of sums of deterministic chaotic variables in unimodal maps assisted by a novel renormalization group (RG) framework associated to the operation of increment of summands and rescaling. In this framework the difference in control parameter from its value at the transition to chaos is the only relevant variable, the trivial fixed point is the Gaussian distribution and a nontrivial fixed point is a multifractal distribution with features similar to those of the Feigenbaum attractor. The crossover between the two fixed points is discussed and the flow toward the trivial fixed point is seen to consist of a sequence of chaotic band mergers.

Fuentes, Miguel A.; Robledo, A.

2010-12-01

93

Common fixed point results for noncommuting mappings without continuity in cone metric spaces

The existence of coincidence points and common fixed points for mappings satisfying certain contractive conditions, without appealing to continuity, in a cone metric space is established. These results generalize several well-known comparable results in the literature.

M. Abbas; G. Jungck

2008-01-01

94

The Problem of Two Fixed Centers: Bifurcations, Actions, Monodromy

A comprehensive analysis of the Euler-Jacobi problem of motion in the field of two fixed attracting centers is given, first classically and then quantum mechanically in semiclassical approximation. The system was originally studied in the context of celestial mechanics but, starting with Pauli's dissertation, became a model for one-electron molecules such as H + 2 (symmetric case of equal centers)

Holger Waalkens; Holger R. Dullin; Peter H. Richter

95

Fixed Points and Stability for a Sum of Two Operators in Locally Convex Spaces.

National Technical Information Service (NTIS)

Some fixed point theorems for a sum of two operators are proved, generalizing to locally convex spaces a fixed point theorem of M. A. Krasnoselskii, for a sum of a completely continuous and a contraction mapping, as well as some of its recent variants. A ...

G. L. Cain M. Z. Nashed

1971-01-01

96

Multiple positive fixed points of nonlinear operators on ordered Banach spaces

The existence of multiple positive fixed points of completely continuous nonlinear operators defined on the cone of an ordered Banach space is considered. The main results give sufficient conditions for such an operator to have two, and in some cases three, positive fixed points. (RWR)

R. W. Leggett; L. R. Williams

1979-01-01

97

The resolution of field identification fixed points in diagonal coset theories

The fixed point resolution problem is solved for diagonal coset theories. The primary fields into which the fixed points are resolved are described by submodules of the branching spaces, obtained as eigenspaces of the automorphisms that implement field identification. To compute the characters and the modular S-matrix we use ‘orbit Lie algebras’ and ‘twining characters’, which were introduced in a

Jürgen Fuchs; Bert Schellekens; Christoph Schweigert

1996-01-01

98

On Park's Open Questions and Some Fixed-Point Theorems for General Contractive Type Mappings

In this paper, we answer two fixed-point questions of Park by constructing ten nontrivial examples and prove some fixed-point theorems for general contractive type mappings which, in turn, generalize, improve, and unify some results due to Fisher, Hegedüs, Hegedüs and Szilágyi, Hikida, Kasahara, Park, Park and Rhoades, and others.

Zeqing Liu

1999-01-01

99

Teaching Hardware Design of Fixed-Point Digital Signal Processing Systems

Signal processing theory and practice are enabling and driving forces behind multimedia de- vices, communications systems, and even such diverse fields as automotive and medical sys- tems. Over 90% of the signal processing systems on the market used fixed-point arithmetic because of the cost, power, and area savings that fixed-point systems provide. However, most colleges and universities do not teach

David V. Anderson; Tyson S. Hall

100

Results in coupled fixed point in non-linear contractive conditions

NASA Astrophysics Data System (ADS)

In this paper we have established some coupled coincidence and coupled common fixed point theorems on (?, phi)-weakly contractive condition for mapping having the g-mixed monotone property in partially ordered generalized metric spaces which generalize some recent fixed point theorems given in the literature.

Khandaqji, Mona; Al-Sharif, Sharifa; Al-Khaleel, Mohammad

2013-04-01

101

The D4–D8 brane system and five dimensional fixed points

We construct dual Type I' string descriptions to five dimensional supersymmetric fixed points with ENf+1 global symmetry. The background is obtained as the near horizon geometry of the D4–D8 brane system in massive Type IIA supergravity. We use the dual description to deduce some properties of the fixed points.

Andreas Brandhuber; Yaron Oz

1999-01-01

102

A modified fixed-point iterative algorithm for image restoration using fourth-order PDE model

In this paper, we propose a modified fixed point iterative algorithm to solve the fourth-order PDE model for image restoration problem. Compared with the standard fixed point algorithm, the proposed algorithm needn?t to compute inverse matrices so that it can speed up the convergence and reduce the roundoff error. Furthermore, we prove the convergence of the proposed algorithm and give

Ting-Ting Wu; Yu-Fei Yang; Zhi-Feng Pang

103

NASA Astrophysics Data System (ADS)

The main focus of the paper is to bring out the differences in performance related issues of Fast-ICA algorithm associated with floating point and fixed point digital signal processing (DSP) platforms. The DSP platforms consisting of TMS320C6713 floating point processor and TMS320C6416 fixed point processor from Texas Instruments have been chosen for this purpose. To study the consistency of performance, the algorithm has been subjected to three different test cases comprising of a mixture of synthetic signals, a mixture of speech signals and a mixture of synthetic signals in presence of noise, respectively. The performance of the Fast-ICA algorithm on floating point and fixed point platform are compared on the basis of accuracy of separation and execution time. Experimental results show insignificant differences in the accuracy of separation and execution time obtained from fixed point processor when compared with those obtained from floating point processor. This clearly strengthens the feasibility issue concerning hardware realization of Fast-ICA on fixed point platform for specific applications.

Patil, Dinesh; Das, Niva; Routray, Aurobinda

2011-01-01

104

A 64-bit orthorectification algorithm using fixed-point arithmetic

NASA Astrophysics Data System (ADS)

As the cost of imaging systems have decreased, the quality and size has increased. This dynamic has made the practicality of many aerial imaging applications achievable such as cost line monitoring and vegetation indexing. Orthorectification is required for many of these applications; however, it is also expensive, computationally. The computational cost is due to oating point operations and divisions inherent in the orthorecti cation process. Two novel algorithm modi cations are proposed which signi cantly reduce the computational cost. The rst modi cation uses xed-point arithmetic in place of the oating point operations. The second replaces the division with a multiplication of the inverse. The result in an increase of 2x of the throughput while remaining within 15% of a pixel size in position.

French, Joseph C.; Balster, Eric J.; Turri, William F.

2013-10-01

105

G-CO Fixed points of rigid motions

NSDL National Science Digital Library

This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: A rigid motion of the plane is a map of the plane to itself which preserves distances between points. Let $f$ be such a function.A point $x$ in the pla...

106

A fixed point theorem for certain operator valued maps

NASA Technical Reports Server (NTRS)

In this paper, we develop a family of Neuberger-like results to find points z epsilon H satisfying L(z)z = z and P(z) = z. This family includes Neuberger's theorem and has the additional property that most of the sequences q sub n converge to idempotent elements of B sub 1(H).

Brown, D. R.; Omalley, M. J.

1978-01-01

107

Implementation Considerations for Automotive Vision Systems on a Fixed-Point DSP

NASA Astrophysics Data System (ADS)

In this chapter we evaluate numerical requirements for implementation of camera-based lateral position detection algorithms, such as lane keep assistant (LKA) and lane departure warning (LDW) on a fixed-point DSP. We first present methods that address the challenges and requirements of fixed-point design process. The flow proposed is targeted at converting C/C++ code with floating-point operations into C code with integer operations that can then be fed through the native C compiler for a fixed-point DSP. Advanced code optimization and an implementation by DSP-specific, fixed-point C code generation are introduced. We then demonstrate the conversion flow on tracking example (extended Kalman filter) using synthetically generated data, and we analyze trade-offs for algorithm implementation in fixed-point arithmetic. By using the techniques described in this chapter speed can be increased by a factor of up to 10 compared to floating-point emulation on fixed-point hardware.

Nikoli?, Zoran

108

A restart algorithm for computing fixed points without an extra dimension

An algorithm to compute a fixed point of an upper semicontinuous point to set mapping using a simplicial subdivision is introduced. The new element of the algorithm is that for a given grid it does not start with a subsimplex but with one (arbitrary) point only; the algorithm will terminate always with a subsimplex. This subsimplex yields an approximation of

G. van der Laan; A. J. J. Talman

1979-01-01

109

Conditions for the Existence of Fixed Points in a Finite System of Kuramoto Oscillators

We present new necessary and sufficient conditions for the existence of fixed points in a finite system of coupled phase oscillators on a complete graph. We use these conditions to derive bounds on the critical coupling.

Mark Verwoerd; Oliver Mason

2007-01-01

110

Fixed point theorems for multi-valued contractive mappings and multi-valued Caristi type mappings

NASA Astrophysics Data System (ADS)

In this paper, the famous Banach contraction principle and Caristi's fixed point theorem are generalized to the case of multi-valued mappings. Our results are extensions of the well-known Nadler's fixed point theorem [S.B. Nadler Jr., Multi-valued contraction mappings, Pacific J. Math. 30 (1969) 475-487], as well as of some Caristi type theorems for multi-valued operators, see [N. Mizoguchi, W. Takahashi, Fixed point theorems for multivalued mappings on complete metric spaces, J. Math. Anal. Appl. 141 (1989) 177-188; J.P. Aubin, Optima and Equilibria. An Introduction to Nonlinear Analysis, Grad. Texts in Math., Springer-Verlag, Berlin, 1998, p. 17; S.S. Zhang, Q. Luo, Set-valued Caristi fixed point theorem and Ekeland's variational principle, Appl. Math. Mech. 10 (2) (1989) 111-113 (in Chinese), English translation: Appl. Math. Mech. (English Ed.) 10 (2) (1989) 119-121], etc.

Feng, Yuqiang; Liu, Sanyang

2006-05-01

111

The aim of this paper is to study a free boundary problem for a uniformly elliptic fully non-linear operator. Under certain assumptions we show that free and fixed boundaries meet tangentially at contact points.

Norayr Matevosyan; Peter A. Markowich

2004-01-01

112

Schaefer-Krasnoselskii fixed point theorems using a usual measure of weak noncompactness

NASA Astrophysics Data System (ADS)

We present some extension of a well-known fixed point theorem due to Burton and Kirk [T.A. Burton, C. Kirk, A fixed point theorem of Krasnoselskii-Schaefer type, Math. Nachr. 189 (1998) 423-431] for the sum of two nonlinear operators one of them compact and the other one a strict contraction. The novelty of our results is that the involved operators need not to be weakly continuous. Finally, an example is given to illustrate our results.

Garcia-Falset, J.; Latrach, K.; Moreno-Gálvez, E.; Taoudi, M.-A.

113

We extend the notion of generalized weakly contraction mappings due to Choudhury et al. (2011) to generalized ?-?-weakly contraction mappings. We show with examples that our new class of mappings is a real generalization of several known classes of mappings. We also establish fixed point results for such mappings in metric spaces. Applying our new results, we obtain fixed point results on ordinary metric spaces, metric spaces endowed with an arbitrary binary relation, and metric spaces endowed with graph.

Latif, Abdul

2014-01-01

114

Conducting fixed points for inhomogeneous quantum wires: A conformally invariant boundary theory

NASA Astrophysics Data System (ADS)

Inhomogeneities and junctions in wires are natural sources of scattering, and hence resistance. A conducting fixed point usually requires an adiabatically smooth system. One notable exception is "healing," which has been predicted in systems with special symmetries, where the system is driven to the homogeneous fixed point. Here we present theoretical results for a different type of conducting fixed point which occurs in inhomogeneous wires with an abrupt jump in hopping and interaction strength. We show that it is always possible to tune the system to an unstable conducting fixed point which does not correspond to translational invariance. We analyze the temperature scaling of correlation functions at and near this fixed point and show that two distinct boundary exponents appear, which correspond to different effective Luttinger liquid parameters. Even though the system consists of two separate interacting parts, the fixed point is described by a single conformally invariant boundary theory. We present details of the general effective bosonic field theory including the mode expansion and the finite size spectrum. The results are confirmed by numerical quantum Monte Carlo simulations on spinless fermions. We predict characteristic experimental signatures of the local density of states near junctions.

Sedlmayr, N.; Morath, D.; Sirker, J.; Eggert, S.; Affleck, I.

2014-01-01

115

A new subdivision for computing fixed points with a homotopy algorithm

In this paper a triangulation is introduced for homotopy methods to compute fixed points on the unit simplex or inRn. This triangulation allows for factors of incrementation of more than two. The factor may be of any size and even different at each level. Also the starting point on a new level may be any gridpoint of the last found

G. van der Laan; A. J. J. Talman

1980-01-01

116

Spatiotemporal Salient Points for Visual Recognition of Human Actions

This paper addresses the problem of human-action recogni- tion by introducing a sparse representation of image sequences as a collec- tion of spatiotemporal events that are localized at points that are salient both in space and time. The spatiotemporal salient points are detected by measuring the variations in the information content of pixel neighborhoods not only in space but also

Antonios Oikonomopoulos; Ioannis Patras; Maja Pantic

2006-01-01

117

Fixed-point bifurcation analysis in biological models using interval polynomials theory.

The paper proposes a systematic method for fixed-point bifurcation analysis in circadian cells and similar biological models using interval polynomials theory. The stages for performing fixed-point bifurcation analysis in such biological systems comprise (i) the computation of fixed points as functions of the bifurcation parameter and (ii) the evaluation of the type of stability for each fixed point through the computation of the eigenvalues of the Jacobian matrix that is associated with the system's nonlinear dynamics model. Stage (ii) requires the computation of the roots of the characteristic polynomial of the Jacobian matrix. This problem is nontrivial since the coefficients of the characteristic polynomial are functions of the bifurcation parameter and the latter varies within intervals. To obtain a clear view about the values of the roots of the characteristic polynomial and about the stability features they provide to the system, the use of interval polynomials theory and particularly of Kharitonov's stability theorem is proposed. In this approach, the study of the stability of a characteristic polynomial with coefficients that vary in intervals is equivalent to the study of the stability of four polynomials with crisp coefficients computed from the boundaries of the aforementioned intervals. The efficiency of the proposed approach for the analysis of fixed-point bifurcations in nonlinear models of biological neurons is tested through numerical and simulation experiments. PMID:24817437

Rigatos, Gerasimos G

2014-06-01

118

One-parameter semigroups of analytic functions, fixed points and the Koenigs function

Analogues of the Berkson-Porta formula for the infinitesimal generator of a one-parameter semigroup of holomorphic maps of the unit disc into itself are obtained in the case when, along with a Denjoy-Wolff point, there also exist other fixed points. With each one-parameter semigroup a so-called Koenigs function is associated, which is a solution, common for all elements of the one-parameter semigroup, of a certain functional equation (Schroeder's equation in the case of an interior Denjoy-Wolff point and Abel's equation in the case of a boundary Denjoy-Wolff point). A parametric representation for classes of Koenigs functions that takes account of the Denjoy-Wolff point and other fixed points of the maps in the one-parameter semigroup is presented. Bibliography: 19 titles.

Goryainov, Victor V; Kudryavtseva, Olga S [Volzhsky Institute of Humanities, Volgograd Region, Volzhsky (Russian Federation)

2011-07-31

119

Some Common Fixed Point Theorems in Complex Valued b-Metric Spaces

Azam et al. (2011), introduce the notion of complex valued metric spaces and obtained common fixed point result for mappings in the context of complex valued metric spaces. Rao et al. (2013) introduce the notion of complex valued b-metric spaces. In this paper, we generalize the results of Azam et al. (2011), and Bhatt et al. (2011), by improving the conditions of contraction to establish the existence and uniqueness of common fixed point for two self-mappings on complex valued b-metric spaces. Some examples are given to illustrate the main results.

Mukheimer, Aiman A.

2014-01-01

120

Non-Fermi-Liquid Fixed Point for an Imbalanced Gas of Fermions in 1+{epsilon} Dimensions

We consider a gas of two species of fermions with population imbalance. Using the renormalization group in d=1+{epsilon} spatial dimensions, we show that for spinless fermions and 2>{epsilon}>0 a fixed point appears at finite attractive coupling where the quasiparticle residue vanishes, and identify this with the transition to Larkin-Ovchinnikov-Fulde-Ferrell order (inhomogeneous superconductivity). When the two species of fermions also carry spin degrees of freedom we find a fixed point indicating a transition to spin density wave order.

James, A. J. A.; Lamacraft, A. [Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4717 (United States)

2010-05-14

121

Fixed Point Results for G-?-Contractive Maps with Application to Boundary Value Problems.

We unify the concepts of G-metric, metric-like, and b-metric to define new notion of generalized b-metric-like space and discuss its topological and structural properties. In addition, certain fixed point theorems for two classes of G- ? -admissible contractive mappings in such spaces are obtained and some new fixed point results are derived in corresponding partially ordered space. Moreover, some examples and an application to the existence of a solution for the first-order periodic boundary value problem are provided here to illustrate the usability of the obtained results. PMID:24895655

Hussain, Nawab; Parvaneh, Vahid; Roshan, Jamal Rezaei

2014-01-01

122

Fixed Point Results for G-?-Contractive Maps with Application to Boundary Value Problems

We unify the concepts of G-metric, metric-like, and b-metric to define new notion of generalized b-metric-like space and discuss its topological and structural properties. In addition, certain fixed point theorems for two classes of G-?-admissible contractive mappings in such spaces are obtained and some new fixed point results are derived in corresponding partially ordered space. Moreover, some examples and an application to the existence of a solution for the first-order periodic boundary value problem are provided here to illustrate the usability of the obtained results.

Roshan, Jamal Rezaei

2014-01-01

123

A least-squares fixed-point iterative algorithm for multiple illumination photoacoustic tomography

The optical absorption of tissues provides important information for clinical and pre-clinical studies. The challenge in recovering optical absorption from photoacoustic images is that the measured pressure depends on absorption and local fluence. One reconstruction approach uses a fixed-point iterative technique based on minimizing the mean-squared error combined with modeling of the light source to determine optical absorption. With this technique, convergence is not guaranteed even with an accurate measure of optical scattering. In this work we demonstrate using simulations that a new multiple illumination least squares fixed-point iteration algorithm improves convergence - even with poor estimates of optical scattering.

Harrison, Tyler; Shao, Peng; Zemp, Roger J.

2013-01-01

124

On a sharpened form of the Schauder fixed-point theorem.

If K is a compact convex subset of a locally convex topological vector space X, we consider a continuous mapping f of K into X. A fixed-point theorem is proved for such a map f under the assumption that for a given continuous realvalued function p on K x X with p(x,y) convex in y and for each point x in K not fixed by f, there exists a point y in the inward set I(K)(x) generated by K at x with p(x,y - f(x)) less than p(x,x - f(x)). For X a Banach space, in particular, this yields a sharp extension and a drastic simplification of the fixed point theory of weakly inward (and weakly outward) mappings. The result comes close in the domain of mappings of compact convex sets to the thrust of fixed point conditions of the Leray-Schauder type for compact maps of sets with interior in X. PMID:16592465

Browder, F E

1977-11-01

125

Bilateral Comparison of Aluminum Fixed-Point Cells Using Standard Platinum Resistance Thermometer

NASA Astrophysics Data System (ADS)

The objective of Project EURAMET 1114 (Bilateral comparison of a freezing point of aluminum) in the field of thermometry is to compare realization of a freezing point of aluminum (660.323 °C) between the Dutch national laboratory VSL and the Slovenian national laboratory MIRS/UL-FE/LMK using a long-stem 25 ? standard platinum resistance thermometer (SPRT). Both laboratories had participated in a number of inter-comparisons on the level of EURAMET and also on BIPM CCT level (VSL). MIRS/UL-FE/LMK laboratory recently acquired a new fixed-point cell which had to be validated in the process of intercomparison. A quartz-sheathed SPRT was selected and calibrated at MIRS/UL-FE/LMK at the aluminum freezing point and at the water triple point. A second set of measurements was made on the same SPRT and at the same fixed points at VSL (NL). After its return, the SPRT was again recalibrated at MIRS/UL-FE/LMK. In the comparison the W value of the SPRT was used. The results of the internal and external intercomparisons confirmed that the new aluminum cell of the MIRS/UL/FE-LMK realizes a temperature that agrees with the VSL aluminum fixed point within the uncertainty limits of both laboratories. Furthermore, the results of this bilateral-comparison were compared with results that both laboratories achieved in the EURAMET K4 (Project 820) and were found to be in agreement.

Bojkovski, J.; Peruzzi, A.; Bosma, R.; Batagelj, V.

2011-08-01

126

NASA Astrophysics Data System (ADS)

In this paper, a mode of using the Dynamic Renormalization Group (DRG) method is suggested in order to cope with inconsistent results obtained when applying it to a continuous family of one-dimensional nonlocal models. The key observation is that the correct fixed-point dynamical system has to be identified during the analysis in order to account for all the relevant terms that are generated under renormalization. This is well established for static problems, however poorly implemented in dynamical ones. An application of this approach to a nonlocal extension of the Kardar-Parisi-Zhang equation resolves certain problems in one-dimension. Namely, obviously problematic predictions are eliminated and the existing exact analytic results are recovered.

Katzav, Eytan

2013-04-01

127

A methodology for evaluating the precision of fixed-point systems

The minimization of cost, power consumption and time-to-market of DSP applications requires the development of methodologies for the automatic implementation of floating-point algorithms in fixed-point architectures. In this paper, a new methodology for evaluating the quality of an implementation through the automatic determination of the Signal to Quantization Noise Ratio (SQNR) is presented. The modelization of the system at the

Daniel Menard; Olivier Sentieys

2002-01-01

128

On the Complexity of Nash Equilibria and Other Fixed Points (Extended Abstract)

We reexamine, what it means to compute Nash equilibria and, more, generally, what it means to compute a fixed point of a given Brouwer function, and we investigate the complexity of the associated problems. Specifically, we study the complexity of the following problem: given a finite game, Gamma, with 3 or more players, and given epsiv > 0, compute a

Kousha Etessami; Mihalis Yannakakis

2007-01-01

129

Control of transient chaos in tent maps near crisis. I. Fixed point targeting

Combinatorial techniques are applied to the symbolic dynamics representing transient chaotic behavior in tent maps in order to solve the problem of Ott-Grebogi-Yorke control to the nontrivial fixed point occurring in such maps. This approach allows ``preimage overlap'' to be treated exactly. Closed forms for both the probability of control being achieved and the average number of iterations to control

D. K. Arrowsmith

2000-01-01

130

Viscosity approximation methods for equilibrium problems and fixed point problems in Hilbert spaces

In this paper, we introduce an iterative scheme by the viscosity approximation method for finding a common element of the set of solutions of an equilibrium problem and the set of fixed points of a nonexpansive mapping in a Hilbert space. Then, we prove a strong convergence theorem which is connected with Combettes and Hirstoaga's result [P.L. Combettes, S.A. Hirstoaga,

Satoru Takahashi; Wataru Takahashi

2007-01-01

131

Memory Recall by Quasi-Fixed-Point Attractors in Oscillator Neural Networks

It is shown that approximate fixed-point attractors rather than synchronized oscillations can be employed by a wide class of neural networks of oscillators to achieve an associative memory recall. This computational ability of oscillator neural networks is ensured by the fact that reduced dynamic equations for phase variables in general involve two terms that can be respectively responsible for the

Tomoki Fukai; Masatoshi Shiino

1995-01-01

132

A Common Fixed Point Theorem in Two Complete L-Fuzzy Metric Spaces

NASA Astrophysics Data System (ADS)

In this paper we first explain the concept L-fuzzy metric spaces and in this sequel explain the nation of Cauchy sequence and convergent in L-fuzzy metric spaces and finally we prove a common fixed point theorem in two complete L-fuzzy metric space.

Sedghi, Shaban; Ghayekhloo, Somayeh; Salimi, Solaleh

2010-11-01

133

L-Fuzzy Fixed Points Theorems for L-Fuzzy Mappings via ??L-Admissible Pair

We define the concept of ??L-admissible for a pair of L-fuzzy mappings and establish the existence of common L-fuzzy fixed point theorem. Our result generalizes some useful results in the literature. We provide an example to support our result.

Rashid, Maliha; Azam, Akbar

2014-01-01

134

A Common Fixed Point Theorem through Weak and SemiCompatibility in Fuzzy Metric Space

NASA Astrophysics Data System (ADS)

In this paper, a common fixed point theorem for six self mappings has been established using the concept of semicompatibility and weak compatibility in Fuzzy metric space, which generalizes the result of Singh B.S., Jain A. and Masoodi A.A. [6

Singh, Deepak; Rathore, M. S.; Sisodia, Krishnapal Singh

2013-03-01

135

A class of simplicial restart fixed point algorithms without an extra dimension

In an earlier paper we introduced an algorithm for approximating a fixed point of a mapping on the product space of unit simplices. Ideas of that paper are used to construct a class of triangulations ofRn. More precisely, for somek, 1 =k = n, and positive integersm1 ? , mk with sumn, a triangulation ofRn is obtained by triangulating the

G. van der Laan; A. J. J. Talman

1981-01-01

136

An improvement of fixed point algorithms by using a good triangulation

We consider measures for triangulations ofRn. A new measure is introduced based on the ratio of the length of the sides and the content of the subsimplices of the triangulation. In a subclass of triangulations, which is appropriate for computing fixed points using simplicial subdivisions, the optimal one according to this measure is calculated and some of its properties are

G. van der Laan; A. J. J. Talman

1980-01-01

137

Convergence theorems on generalized equilibrium problems and fixed point problems with applications

Received 17 December 2008, revised 6 February 2009, accepted 18 March 2009 Abstract. In this paper, we introduce an iterative algorithm for finding a common element in the set of solutions to generalized equilibrium problems and a set of fixed points of strict pseudo-contractions. Strong convergence theorems are established in the framework of Hilbert spaces. The results presented in this

Xiaolong Qin; Shin Min Kang; Y J Cho

2009-01-01

138

Fixed point controllers and stabilization of the cart-pole system and the rotating pendulum

We consider stabilization of nonlinear systems in a special normal form as the cascade of a nonlinear subsystem and a linear subsystem. These systems do not possess any particular triangular structure. Despite this fact, we show how a backstepping type procedure applied to these systems naturally leads to a fixed point equation in the control input. We give conditions for

Reza Olfati-Saber

1999-01-01

139

Fixed point analysis of a scalar theory with an external field

A momentum dependent projection of the Wegner-Hougton equation is derived for a scalar theory coupled to an external field. This formalism is useful to discuss the phase diagram of the theory. In particular we study some properties of the Gaussian fixed point. {copyright} {ital 1997} {ital The American Physical Society}

Bonanno, A. [Istituto di Astronomia, Universita di Catania, Viale Andrea Doria 6, 95125 Catania (Italy)] [Istituto di Astronomia, Universita di Catania, Viale Andrea Doria 6, 95125 Catania (Italy); Zappala, D. [Dipartimento di Fisica, Universita di Catania, and INFN, sezione di Catania, Corso Italia 57, 95129 Catania (Italy)] [Dipartimento di Fisica, Universita di Catania, and INFN, sezione di Catania, Corso Italia 57, 95129 Catania (Italy)

1997-09-01

140

L-fuzzy fixed points theorems for L-fuzzy mappings via ??L-admissible pair.

We define the concept of ??L-admissible for a pair of L-fuzzy mappings and establish the existence of common L-fuzzy fixed point theorem. Our result generalizes some useful results in the literature. We provide an example to support our result. PMID:24688441

Rashid, Maliha; Azam, Akbar; Mehmood, Nayyar

2014-01-01

141

Fixed point results of T-Kannan contraction on generalized distance in cone metric spaces

NASA Astrophysics Data System (ADS)

In this paper, we prove the existence and uniqueness of the fixed point in some type of mappings which satisfy the T-Kannan contraction on generalized distance in cone metric spaces. The presented theorem extend and generalize several well-known comparable results in literature.

Fadail, Zaid Mohammed; Ahmad, Abd Ghafur Bin

2014-06-01

142

NASA Astrophysics Data System (ADS)

The objective of project EURAMET 1127 (Bilateral comparison of triple point of mercury and melting point of gallium) in the field of thermometry is to compare realization of a triple point of mercury (-38.8344 °C) and melting point of gallium (29.7646 °C) between the Slovenian national laboratory MIRS/UL-FE/LMK and the Croatian national laboratory HMI/FSB-LPM using a long-stem 25 ? standard platinum resistance thermometer (SPRT). MIRS/UL/FE-LMK participated in a number of intercomparisons on the level of EURAMET. On the other hand, the HMI/LPM-FSB laboratory recently acquired new fixed-point cells which had to be evaluated in the process of intercomparisons. A quartz-sheathed SPRT has been selected and calibrated at HMI/LPM-FSB at the triple point of mercury, the melting point of gallium, and the water triple point. A second set of measurements was made at MIRS/UL/FE-LMK. After its return, the SPRT was again recalibrated at HMI/LPM-FSB. In the comparison, the W value of the SPRT has been used. Results of the bilateral intercomparison confirmed that the new gallium cell of the HMI/LPM-FSB has a value that is within uncertainty limits of both laboratories that participated in the exercise, while the mercury cell experienced problems. After further research, a small leakage in the mercury fixed-point cell has been found.

Bojkovski, J.; Veliki, T.; Zvizdi?, D.; Drnovšek, J.

2011-08-01

143

Many-Body Localization in One Dimension as a Dynamical Renormalization Group Fixed Point

NASA Astrophysics Data System (ADS)

We formulate a dynamical real space renormalization group (RG) approach to describe the time evolution of a random spin-1/2 chain, or interacting fermions, initialized in a state with fixed particle positions. Within this approach we identify a many-body localized state of the chain as a dynamical infinite randomness fixed point. Near this fixed point our method becomes asymptotically exact, allowing analytic calculation of time dependent quantities. In particular, we explain the striking universal features in the growth of the entanglement seen in recent numerical simulations: unbounded logarithmic growth delayed by a time inversely proportional to the interaction strength. This is in striking contrast to the much slower entropy growth as log?log?t found for noninteracting fermions with bond disorder. Nonetheless, even the interacting system does not thermalize in the long time limit. We attribute this to an infinite set of approximate integrals of motion revealed in the course of the RG flow, which become asymptotically exact conservation laws at the fixed point. Hence we identify the many-body localized state with an emergent generalized Gibbs ensemble.

Vosk, Ronen; Altman, Ehud

2013-02-01

144

Bilateral ITS-90 comparison at WC-C peritectic fixed point between NIM and NPL

NASA Astrophysics Data System (ADS)

The WC-C peritectic fixed point, nominal melting and freezing temperature 2747 °C, shows extremely good metrological potential. Elsewhere, we published a prototype scale comparison of the ITS-90 between NPL, NIM and CEM, using high temperature eutectic fixed points (HTFPs) of Co-C (1324 °C), Pt-C (1738 °C), and Re-C (2474 °C). In this paper we present the further results of the bilateral comparison of the ITS-90 at an even higher temperature, 2747 °C, between NIM and NPL using WC-C peritectic fixed points. A NIM single zone high temperature furnace, model Chino IR-80, was modified to extend its temperature to 2800 °C. Then, an NPL researcher, on secondment to NIM, filled two WC-C cells in the modified furnace in a vertical position. The two WC-C cells were then realized in the same furnace, in an horizontal position. Their melting temperatures, defined by the inflection point of the melting curves, were measured by a linear pyrometer, model NIM-PSP. NIM's ITS-90 scale was assigned to the two cells, which were then transported to NPL. The realization of NPL's ITS-90 was then assigned to the two cells by using a model HT9500 Thermogauge furnace to realize the fixed points and a linear pyrometer, model LP3, to determine their temperature. The difference from the mean value of the NIM and NPL ITS-90 values for the WC-C points was derived. This allowed us to compare ITS-90 as realized by the two institutes and to determine the uncertainty in the scale comparison.

Dong, W.; Lowe, D. H.; Lu, X.; Machin, G.; Yuan, Z.; Wang, T.; Bloembergen, P.; Xiao, C.

2013-09-01

145

Computational fixed-point theory for differential delay equations with multiple time lags

NASA Astrophysics Data System (ADS)

We introduce a general computational fixed-point method to prove existence of periodic solutions of differential delay equations with multiple time lags. The idea of such a method is to compute numerical approximations of periodic solutions using Newton's method applied on a finite dimensional projection, to derive a set of analytic estimates to bound the truncation error term and finally to use this explicit information to verify computationally the hypotheses of a contraction mapping theorem in a given Banach space. The fixed point so obtained gives us the desired periodic solution. We provide two applications. The first one is a proof of coexistence of three periodic solutions for a given delay equation with two time lags, and the second one provides rigorous computations of several nontrivial periodic solutions for a delay equation with three time lags.

Kiss, Gábor; Lessard, Jean-Philippe

146

Comparison of Co-C eutectic fixed-point cells between VNIIM and VNIIOFI

NASA Astrophysics Data System (ADS)

Two national metrological institutes of the Russian Federation, VNIIM and VNIIOFI, take part in the international research plan of CCT WG5 for investigation of high-temperature fixed points (HTFP). In the framework of this CCT-WG5 HTFP Research Plan the both institutes have designed and built independently cobalt-carbon (Co-C) eutectic radiation cells. The comparison of the Co-C cells developed by the institutes was carried out with the aim of determination of a difference in the melting temperature due to difference in the constructional characteristics of the cells. The radiance-mode radiation thermometers with central wavelength nearby 650 nm were used for the fixed-point melting temperature measurements. The article presents preliminary results of the comparison, which shows agreement between melting temperature of the compared cells within 20 mK. The details of the comparison are reported.

Sild, Y.; Khlevnoy, B.; Matveyev, M.; Grigorieva, I. A.; Fuksov, V. M.

2013-09-01

147

The algebraic multigrid projection for eigenvalue problems; backrotations and multigrid fixed points

NASA Technical Reports Server (NTRS)

The periods of the theorem for the algebraic multigrid projection (MGP) for eigenvalue problems, and of the multigrid fixed point theorem for multigrid cycles combining MGP with backrotations, are presented. The MGP and the backrotations are central eigenvector separation techniques for multigrid eigenvalue algorithms. They allow computation on coarse levels of eigenvalues of a given eigenvalue problem, and are efficient tools in the computation of eigenvectors.

Costiner, Sorin; Taasan, Shlomo

1994-01-01

148

A comparison of fixed-point 2D 9×7 discrete wavelet transform implementations

We describe three 2D discrete wavelet transform fixed-point implementations and compare them in terms of quantization error for the Daubechies 9×7 filter bank. The three implementations are the polyphase form, lifting scheme, and reduced scaling lifting scheme. Experimental results show that the reduced scaling lifting scheme is more robust than the other schemes. Also, the number of cycles the implementations

Hyung Cook Kim; Edward J. Delp

2002-01-01

149

Rapid re-convergences to ambiguity-fixed solutions in precise point positioning

Integer ambiguity resolution at a single receiver can be achieved if the fractional-cycle biases are separated from the ambiguity\\u000a estimates in precise point positioning (PPP). Despite the improved positioning accuracy by such integer resolution, the convergence\\u000a to an ambiguity-fixed solution normally requires a few tens of minutes. Even worse, these convergences can repeatedly occur\\u000a on the occasion of loss of

Jianghui Geng; Xiaolin Meng; Alan H. Dodson; Maorong Ge; Felix N. Teferle

2010-01-01

150

A note on the split common fixed-point problem for quasi-nonexpansive operators

Based on the very recent work by Censor and Segal (2009) [1], and inspired by Xu (2006) [9], Zhao and Yang (2005) [10], and Bauschke and Combettes (2001) [2], we introduce and analyze an algorithm for solving the split common fixed-point problem for the wide class of quasi-nonexpansive operators in Hilbert spaces. Our results improve and develop previously discussed feasibility problems and related

A. Moudafi

2011-01-01

151

Fixed-point fluid–structure interaction solvers with dynamic relaxation

A fixed-point fluid–structure interaction (FSI) solver with dynamic relaxation is revisited. New developments and insights\\u000a gained in recent years motivated us to present an FSI solver with simplicity and robustness in a wide range of applications.\\u000a Particular emphasis is placed on the calculation of the relaxation parameter by both Aitken’s $${\\\\Delta^{2}}$$ method and the method of steepest descent. These methods

Ulrich Küttler; Wolfgang A. Wall

2008-01-01

152

A Fast Fixed Point Algorithm for Total Variation Deblurring and Segmentation

In this paper, we propose a fast fixed point algorithm and apply it to total variation (TV) deblurring and segmentation. The\\u000a TV-based models can be written in the form of a general minimization problem. The novel method is derived from the idea of\\u000a establishing the relation between solutions of the general minimization problem and new variables, which can be obtained

Dai-Qiang Chen; Hui Zhang; Li-Zhi Cheng

153

NASA Astrophysics Data System (ADS)

Most computers in the past have been equipped with floating point processing capabilities, allowing an easy and brute-force solution for the machine computation errors, not requiring any specific tailoring of the computation in nearly hundred percent of situations. However, the computation needed for the adaptive optics real-time control in 30-50 meter telescopes is big enough to cause trouble to conventional von-Neumann processors, even if Moore's Law is valid for the next years. Field Programmable Gate Array (FPGAs) have been proposed as a viable alternative to cope with such computation needs[1,2], but--at least today's chips--will require fixed-point arithmetic to be used instead. It is then important to evaluate up to what point the accuracy and stability of the control system will be affected by this limitation. This paper presents the simulation and laboratory results of the comparison between both arithmetics, specifically evaluated in an adaptive optics system. The real-time controller has been modeled as black box having as input the wavefront sensor camera digital output data, providing a digital output to the actuators of the deformable mirror, and with the task of internally computing all outputs from the inputs. MATLAB fixed-point library has been used to evaluate the effect of different precision lengths (5-10 fractional bits) in the computation of the Shack-Hartmann subaperture centroid, in comparison with the reference 64-bit floating-point arithmetic and with the noise floor of the real system, concluding that the effect of the limited precision can be overcome by adequately selecting the number of fractional bits used in the representation, and tailoring that number with the needs at every step of the algorithm.

Martín-Hernando, Yolanda; Rodríguez-Ramos, Luis F.; Garcia-Talavera, Marcos R.

2008-07-01

154

National Technical Information Service (NTIS)

L.E.J. Brouwer's fixed-point theorem proves the existence of a fixed-point in a finite-dimensional space which is both convex and bounded, but provides no means of determining its position. For the case of a one-dimensional space, Marvin Shinbrot uses a g...

C. E. S. Lindgren

1970-01-01

155

Presentation functions, fixed points, and a theory of scaling function dynamics

Presentation functions provide the time-ordered points of the forward dynamics of a system as successive inverse images. They generally determine objects constructed on trees, regular or otherwise, and immediately determine a functional form of the transfer matrix of these systems. Presentation functions for regular binary trees determine the associated forward dynamics to be that of a period doubling fixed point. They are generally parametrized by the trajectory scaling function of the dynamics in a natural way. The requirement that the forward dynamics be smooth with a critical point determines a complete set of equations whose solution is the scaling function. These equations are compatible with a dynamics in the space of scalings which is conjectured, with numerical and intuitive support, to possess its solution as a unique, globally attracting fixed point. It is argued that such dynamics is to be sought as a program for the solution of chaotic dynamics. In the course of the exposition new information pertaining to universal mode locking is presented.

Feigenbaum, M.J.

1988-08-01

156

NASA Astrophysics Data System (ADS)

Spatial transformations whose kernels employ sinusoidal functions for the decorrelation of signals remain as fundamental components of image and video coding systems. Practical implementations are designed in fixed precision for which the most challenging task is to approximate these constants with values that are both efficient in terms of complexity and accurate with respect to their mathematical definitions. Scaled architectures, for example, as used in the implementations of the order-8 Discrete Cosine Transform and its corresponding inverse both specified in ISO/IEC 23002-2 (MPEG C Pt. 2), can be utilized to mitigate the complexity of these approximations. That is, the implementation of the transform can be designed such that it is completed in two stages: 1) the main transform matrix in which the sinusoidal constants are roughly approximated, and 2) a separate scaling stage to further refine the approximations. This paper describes a methodology termed the Common Factor Method, for finding fixed-point approximations of such irrational values suitable for use in scaled architectures. The order-16 Discrete Cosine Transform provides a framework in which to demonstrate the methodology, but the methodology itself can be employed to design fixed-point implementations of other linear transformations.

Hinds, Arianne T.

2011-09-01

157

NASA Astrophysics Data System (ADS)

Recently, the minimization of a sum of two convex functions has received considerable interest in a variational image restoration model. In this paper, we propose a general algorithmic framework for solving a separable convex minimization problem from the point of view of fixed point algorithms based on proximity operators (Moreau 1962 C. R. Acad. Sci., Paris I 255 2897-99). Motivated by proximal forward-backward splitting proposed in Combettes and Wajs (2005 Multiscale Model. Simul. 4 1168-200) and fixed point algorithms based on the proximity operator (FP2O) for image denoising (Micchelli et al 2011 Inverse Problems 27 45009-38), we design a primal-dual fixed point algorithm based on the proximity operator (PDFP2O? for ? ? [0, 1)) and obtain a scheme with a closed-form solution for each iteration. Using the firmly nonexpansive properties of the proximity operator and with the help of a special norm over a product space, we achieve the convergence of the proposed PDFP2O? algorithm. Moreover, under some stronger assumptions, we can prove the global linear convergence of the proposed algorithm. We also give the connection of the proposed algorithm with other existing first-order methods. Finally, we illustrate the efficiency of PDFP2O? through some numerical examples on image supper-resolution, computerized tomographic reconstruction and parallel magnetic resonance imaging. Generally speaking, our method PDFP2O (? = 0) is comparable with other state-of-the-art methods in numerical performance, while it has some advantages on parameter selection in real applications.

Chen, Peijun; Huang, Jianguo; Zhang, Xiaoqun

2013-02-01

158

Estimating the Contribution of Impurities to the Uncertainty of Metal Fixed-Point Temperatures

NASA Astrophysics Data System (ADS)

The estimation of the uncertainty component attributable to impurities remains a central and important topic of fixed-point research. Various methods are available for this estimation, depending on the extent of the available information. The sum of individual estimates method has considerable appeal where there is adequate knowledge of the sensitivity coefficients for each of the impurity elements and sufficiently low uncertainty regarding their concentrations. The overall maximum estimate (OME) forsakes the behavior of the individual elements by assuming that the cryoscopic constant adequately represents (or is an upper bound for) the sensitivity coefficients of the individual impurities. Validation of these methods using melting and/or freezing curves is recommended to provide confidence. Recent investigations of indium, tin, and zinc fixed points are reported. Glow discharge mass spectrometry was used to determine the impurity concentrations of the metals used to fill the cells. Melting curves were analyzed to derive an experimental overall impurity concentration (assuming that all impurities have a sensitivity coefficient equivalent to that of the cryoscopic constant). The two values (chemical and experimental) for the overall impurity concentrations were then compared. Based on the data obtained, the pragmatic approach of choosing the larger of the chemical and experimentally derived quantities as the best estimate of the influence of impurities on the temperature of the freezing point is suggested rather than relying solely on the chemical analysis and the OME method to derive the uncertainty component attributable to impurities.

Hill, K. D.

2014-06-01

159

Design and Evaluation of Large-Aperture Gallium Fixed-Point Blackbody

NASA Astrophysics Data System (ADS)

To complement existing water bath blackbodies that now serve as NIST primary standard sources in the temperature range from 15 °C to 75 °C, a gallium fixed-point blackbody has been recently built. The main objectives of the project included creating an extended-area radiation source with a target emissivity of 0.9999 capable of operating either inside a cryo-vacuum chamber or in a standard laboratory environment. A minimum aperture diameter of 45 mm is necessary for the calibration of radiometers with a collimated input geometry or large spot size. This article describes the design and performance evaluation of the gallium fixed-point blackbody, including the calculation and measurements of directional effective emissivity, estimates of uncertainty due to the temperature drop across the interface between the pure metal and radiating surfaces, as well as the radiometrically obtained spatial uniformity of the radiance temperature and the melting plateau stability. Another important test is the measurement of the cavity reflectance, which was achieved by using total integrated scatter measurements at a laser wavelength of 10.6 ?m. The result allows one to predict the performance under the low-background conditions of a cryo-chamber. Finally, results of the spectral radiance comparison with the NIST water-bath blackbody are provided. The experimental results are in good agreement with predicted values and demonstrate the potential of our approach. It is anticipated that, after completion of the characterization, a similar source operating at the water triple point will be constructed.

Khromchenko, V. B.; Mekhontsev, S. N.; Hanssen, L. M.

2009-02-01

160

Uncertainty due to non-linearity in radiation thermometers calibrated by multiple fixed points

NASA Astrophysics Data System (ADS)

A new method to estimate the uncertainty due to non-linearity is described on the n = 3 scheme basis. The expression of uncertainty is mathematically derived applying the random walk method. The expression is simple and requires only the temperatures of the fixed points and a relative uncertainty value for each flux-doubling derived from the non-linearity measurement. We also present an example of the method, in which the uncertainty of temperature measurement by a radiation thermometer is calculated on the basis of non-linearity measurement.

Yamaguchi, Y.; Yamada, Y.

2013-09-01

161

Uncertainty due to non-linearity in radiation thermometers calibrated by multiple fixed points

A new method to estimate the uncertainty due to non-linearity is described on the n= 3 scheme basis. The expression of uncertainty is mathematically derived applying the random walk method. The expression is simple and requires only the temperatures of the fixed points and a relative uncertainty value for each flux-doubling derived from the non-linearity measurement. We also present an example of the method, in which the uncertainty of temperature measurement by a radiation thermometer is calculated on the basis of non-linearity measurement.

Yamaguchi, Y.; Yamada, Y. [National Metrology Institute of Japan, AIST, Tsukuba, Ibaraki (Japan)] [National Metrology Institute of Japan, AIST, Tsukuba, Ibaraki (Japan)

2013-09-11

162

Hints of 5d fixed point theories from non-Abelian T-duality

NASA Astrophysics Data System (ADS)

In this paper we investigate the properties of the putative 5d fixed point theory that should be dual, through the holographic correspondence, to the new supersymmetric AdS 6 solution constructed in [1]. This solution is the result of a non-Abelian T-duality transformation on the known supersymmetric AdS 6 solution of massive Type IIA. The analysis of the charge quantization conditions seems to put constraints on the global properties of the background, which, combined with the information extracted from considering probe branes, suggests a 2-node quiver candidate for the dual CFT.

Lozano, Yolanda; Colgáin, Eoin Ó.; Rodríguez-Gómez, Diego

2014-05-01

163

New Sealed Cells for Realization of Cryogenic Fixed Points at NMIJ/AIST

NASA Astrophysics Data System (ADS)

New sealed cells have been developed at the National Metrology Institute of Japan (NMIJ), which are used for realization of the cryogenic fixed points of the International Temperature Scale of 1990. A metal O-ring made of stainless steel is introduced as a sealing device for the sealed cells. The triple point of equilibrium hydrogen (e-H2) is realized using the new sealed cells containing hydrogen and ferric oxy-hydroxide as a catalyst for the ortho-para equilibration. Double anomalous peaks on the heat capacity curves are observed at temperatures just below the triple point, but they are suppressed by reducing the amount of the catalyst. The reduction of the amount of catalyst allows one to obtain more reliable melting curves for e-H2. The triple-point temperature of e-H2 obtained by the new sealed cells is in good agreement with those reported previously in measurements of open cells by assuming that the dependence of the triple-point temperature on the deuterium content is 5.4 ?K per ppm of deuterium in hydrogen.

Nakano, Tohru; Tamura, Osamu; Sakurai, Hirohisa

2003-09-01

164

Errors Analysis in GPS Precise Point Positioning: Impact of Ambiguity Fixing

NASA Astrophysics Data System (ADS)

GNSS geodetic positioning using the classical double-difference approach may have some limitations. For example, fixing ambiguities can be challenging for long baselines, while processing short baseline only give the relative displacement between the two stations. In this context and thanks to the continuous improvement of IGS GNSS orbit and clock products, the Precise Point Positioning (PPP) technique appears in the literature as a powerful alternative. If all local Earth deformations are correctly taken into account, residuals of position time series may be used to assess the processing quality in terms of receiver performance and environment, constellation orbits and clocks error projection, and processing options pertinence. The main limitation of most of the current PPP processing strategies is that ambiguities can not be fixed to integer values. However, Mercier et al. (2008) demonstrated that GPS satellite “electronic” biases can be a priori identified in such a way that using a consistent set of GPS orbits, clocks and biases, phase ambiguities recover their integer nature. The CNES-CLS IGS Analysis Center is being providing such set of data since August 2010. This study evaluate the performance of PPP in front of the nowadays requirements of geodesy. We processed data from several IGS sites in order to compute coordinate series on a daily basis but also at higher frequencies (down to 30 second interval). We investigated both the impact of the processing batch duration from hours to several days and the cut-off elevation angle. Various spurious “non geophysical” signals (random, periodic, jumps...)appeared in our series. Especially artificial "midnight jumps" when adopting the usual 24-hours batch solutions (when satellite passes were cut at 0h). The impact of fixing ambiguities on PPP solutions has been investigated. We demonstrate that most of the artifacts affecting “floating” PPP solutions disappeared when ambiguities were fixed.

Perosanz, F.; Fund, F.; Mercier, F.; Loyer, S.; Capdeville, H.

2010-12-01

165

Phase diagram and strong-coupling fixed point in the disordered O(n) loop model

NASA Astrophysics Data System (ADS)

We study the phase diagram and critical properties of the two-dimensional disordered O(n) loop model. The renormalization group (RG) flow is extracted from the landscape of the effective central charge c obtained by the transfer matrix method. We find a line of multicritical fixed points (FPs) at strong randomness for n > nc ? 0.5. We also find a line of stable random FPs for nc < n < 1, whose c and critical exponents agree well with the 1 ? n expansion results. The multicritical FP at n = 1 has c = 0.4612(4), which suggests that it belongs to the universality class of the Nishimori point in the random-bond Ising model. For n > 2, we find another critical line that connects the hard-hexagon FP in the pure model to a finite-randomness zero-temperature FP .

Shimada, H.; Jacobsen, J. L.; Kamiya, Y.

2014-03-01

166

Development of a new radiometer for the thermodynamic measurement of high temperature fixed points

NASA Astrophysics Data System (ADS)

The National Physical Laboratory (NPL) has developed a new radiometer to measure the thermodynamic melting point temperatures of high temperature fixed points with ultra-low uncertainties. In comparison with the NPL's Absolute Radiation Thermometer (ART), the "THermodynamic Optical Radiometer" (THOR) is more portable and compact, with a much lower size-of-source effect and improved performance in other parameters such as temperature sensitivity. It has been designed for calibration as a whole instrument via the radiance method, removing the need to calibrate the individual subcomponents, as required by ART, and thereby reducing uncertainties. In addition, the calibration approach has been improved through a new integrating sphere that has been designed to have greater uniformity.

Dury, M. R.; Goodman, T. M.; Lowe, D. H.; Machin, G.; Woolliams, E. R.

2013-09-01

167

Quasi-Gaussian fixed points and factorial cumulants in nuclear multifragmentation

NASA Astrophysics Data System (ADS)

We re-analyze the conditions for the phenomenon of intermittency (self-similar fluctuations) to occur in models of multifragmentation. Analyzing two different mechanisms, the bond-percolation and the ERW (Elattari, Richert and Wagner) statistical fragmentation models, we point out a common quasi-Gaussian shape of the total multiplicity distribution in the critical range. The fixed-point property is also observed for the multiplicity of the second bin. Fluctuations are studied using scaled factorial cumulants instead of scaled factorial moments. The second-order cumulant displays the intermittency signal while higher order cumulants are equal to zero, revealing a large information redundancy in scaled factorial moments. A practical criterion is proposed to identify the Gaussian feature of light-fragment production, distinguishing between a self-similarity mechanism (ERW) and the superposition of independent sources (percolation).

Lacroix, D.; Peschanski, R.

1997-02-01

168

Development of a new radiometer for the thermodynamic measurement of high temperature fixed points

The National Physical Laboratory (NPL) has developed a new radiometer to measure the thermodynamic melting point temperatures of high temperature fixed points with ultra-low uncertainties. In comparison with the NPL's Absolute Radiation Thermometer (ART), the 'THermodynamic Optical Radiometer' (THOR) is more portable and compact, with a much lower size-of-source effect and improved performance in other parameters such as temperature sensitivity. It has been designed for calibration as a whole instrument via the radiance method, removing the need to calibrate the individual subcomponents, as required by ART, and thereby reducing uncertainties. In addition, the calibration approach has been improved through a new integrating sphere that has been designed to have greater uniformity.

Dury, M. R.; Goodman, T. M.; Lowe, D. H.; Machin, G.; Woolliams, E. R. [National Physical Laboratory, Teddington (United Kingdom)] [National Physical Laboratory, Teddington (United Kingdom)

2013-09-11

169

Epsilon expansion for multicritical fixed points and exact renormalisation group equations

The Polchinski version of the exact renormalisation group equations is applied to multicritical fixed points, which are present for dimensions between two and four, for scalar theories using both the local potential approximation and its extension, the derivative expansion. The results are compared with the epsilon expansion by showing that the nonlinear differential equations may be linearised at each multicritical point and the epsilon expansion treated as a perturbative expansion. The results for critical exponents are compared with corresponding epsilon expansion results from standard perturbation theory. The results provide a test for the validity of the local potential approximation and also the derivative expansion. An alternative truncation of the exact RG equation leads to equations which are similar to those found in the derivative expansion but which gives correct results for critical exponents to order {epsilon} and also for the field anomalous dimension to order {epsilon}{sup 2}. An exact marginal operator for the full RG equations is also constructed.

O'Dwyer, J. [Department of Applied Mathematics and Theoretical Physics, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)], E-mail: jpo23@damtp.cam.ac.uk; Osborn, H. [Department of Applied Mathematics and Theoretical Physics, Wilberforce Road, Cambridge CB3 0WA (United Kingdom)], E-mail: ho@damtp.cam.ac.uk

2008-08-15

170

Quantum-corrected drift-diffusion models: Solution fixed point map and finite element approximation

NASA Astrophysics Data System (ADS)

This article deals with the analysis of the functional iteration, denoted Generalized Gummel Map (GGM), proposed in [C. de Falco, A.L. Lacaita, E. Gatti, R. Sacco, Quantum-Corrected Drift-Diffusion Models for Transport in Semiconductor Devices, J. Comp. Phys. 204 (2) (2005) 533-561] for the decoupled solution of the Quantum Drift-Diffusion (QDD) model. The solution of the problem is characterized as being a fixed point of the GGM, which permits the establishment of a close link between the theoretical existence analysis and the implementation of a numerical tool, which was lacking in previous non-constructive proofs [N.B. Abdallah, A. Unterreiter, On the stationary quantum drift-diffusion model, Z. Angew. Math. Phys. 49 (1998) 251-275, R. Pinnau, A. Unterreiter, The stationary current-voltage characteristics of the quantum drift-diffusion model, SIAM J. Numer. Anal. 37 (1) (1999) 211-245]. The finite element approximation of the GGM is illustrated, and the main properties of the numerical fixed point map (discrete maximum principle and order of convergence) are discussed. Numerical results on realistic nanoscale devices are included to support the theoretical conclusions.

de Falco, Carlo; Jerome, Joseph W.; Sacco, Riccardo

2009-03-01

171

Quantum-corrected drift-diffusion models: Solution fixed point map and finite element approximation

This article deals with the analysis of the functional iteration, denoted Generalized Gummel Map (GGM), proposed in [C. de Falco, A.L. Lacaita, E. Gatti, R. Sacco, Quantum-Corrected Drift-Diffusion Models for Transport in Semiconductor Devices, J. Comp. Phys. 204 (2) (2005) 533-561] for the decoupled solution of the Quantum Drift-Diffusion (QDD) model. The solution of the problem is characterized as being a fixed point of the GGM, which permits the establishment of a close link between the theoretical existence analysis and the implementation of a numerical tool, which was lacking in previous non-constructive proofs [N.B. Abdallah, A. Unterreiter, On the stationary quantum drift-diffusion model, Z. Angew. Math. Phys. 49 (1998) 251-275, R. Pinnau, A. Unterreiter, The stationary current-voltage characteristics of the quantum drift-diffusion model, SIAM J. Numer. Anal. 37 (1) (1999) 211-245]. The finite element approximation of the GGM is illustrated, and the main properties of the numerical fixed point map (discrete maximum principle and order of convergence) are discussed. Numerical results on realistic nanoscale devices are included to support the theoretical conclusions.

Falco, Carlo de [School of Mathematical Sciences, Dublin City University, Glasnevin, Dublin 9 (Ireland); Jerome, Joseph W. [Department of Mathematics, Northwestern University, 2033 Sheridan Road, Evanston, IL 60208-2730 (United States); Sacco, Riccardo [Dipartimento di Matematica 'F.Brioschi', Politecnico di Milano, via Bonardi 9, 20133 Milano (Italy)], E-mail: riccardo.sacco@polimi.it

2009-03-20

172

Use of Eutectic Fixed Points to Characterize a Spectrometer for Earth Observations

NASA Astrophysics Data System (ADS)

A small palm-sized, reference spectrometer, mounted on a remote-controlled model helicopter is being developed and tested by the National Physical Laboratory (NPL) in conjunction with City University, London. The developed system will be used as a key element for field vicarious calibration of optical earth observation systems in the visible-near infrared (VNIR) region. The spectrometer is hand held, low weight, and uses a photodiode array. It has good stray light rejection and wide spectral coverage, allowing simultaneous measurements from 400 to 900 nm. The spectrometer is traceable to NPL’s primary standard cryogenic radiometer via a high-temperature metal-carbon eutectic fixed-point blackbody. Once the fixed-point temperature has been determined (using filter radiometry), the eutectic provides a high emissivity and high stability source of known spectral radiance over the emitted spectral range. All wavelength channels of the spectrometer can be calibrated simultaneously using the eutectic transition without the need for additional instrumentation. The spectrometer itself has been characterized for stray light performance and wavelength accuracy. Its long-term and transportation stability has been proven in an experiment that determined the “World’s Bluest Sky”—a process that involved 56 flights, covering 100,000 km in 72 days. This vicarious calibration methodology using a eutectic standard is presented alongside the preliminary results of an evaluation study of the spectrometer characteristics.

Salim, Saber G. R.; Fox, Nigel P.; Woolliams, Emma R.; Winkler, Rainer; Pegrum, Heather M.; Sun, Tong; Grattan, Ken T. V.

2007-12-01

173

Optimization of the thermogauge furnace for realizing high temperature fixed points

NASA Astrophysics Data System (ADS)

The thermogauge furnace was commonly used in many NMIs as a blackbody source for calibration of the radiation thermometer. It can also be used for realizing the high temperature fixed point(HTFP). According to our experience, when realizing HTFP we need the furnace provide relative good temperature uniformity to avoid the possible damage to the HTFP. To improve temperature uniformity in the furnace, the furnace tube was machined near the tube ends with a help of a simulation analysis by "ansys workbench". Temperature distributions before and after optimization were measured and compared at 1300 °C, 1700°C, 2500 °C, which roughly correspond to Co-C(1324 °C), Pt-C(1738 °C) and Re-C(2474 °C), respectively. The results clearly indicate that through machining the tube the temperature uniformity of the Thermogage furnace can be remarkably improved. A Pt-C high temperature fixed point was realized in the modified Thermogauge furnace subsequently, the plateaus were compared with what obtained using old heater, and the results were presented in this paper.

Wang, T.; Dong, W.; Liu, F.

2013-09-01

174

Optimization of the thermogauge furnace for realizing high temperature fixed points

The thermogauge furnace was commonly used in many NMIs as a blackbody source for calibration of the radiation thermometer. It can also be used for realizing the high temperature fixed point(HTFP). According to our experience, when realizing HTFP we need the furnace provide relative good temperature uniformity to avoid the possible damage to the HTFP. To improve temperature uniformity in the furnace, the furnace tube was machined near the tube ends with a help of a simulation analysis by 'ansys workbench'. Temperature distributions before and after optimization were measured and compared at 1300 °C, 1700°C, 2500 °C, which roughly correspond to Co-C(1324 °C), Pt-C(1738 °C) and Re-C(2474 °C), respectively. The results clearly indicate that through machining the tube the temperature uniformity of the Thermogage furnace can be remarkably improved. A Pt-C high temperature fixed point was realized in the modified Thermogauge furnace subsequently, the plateaus were compared with what obtained using old heater, and the results were presented in this paper.

Wang, T.; Dong, W. [National Institute of Metrology (NIM), Beijing (China)] [National Institute of Metrology (NIM), Beijing (China); Liu, F. [AVIC China Precision Engineering Institute for Aircraft Industry, Beijing (China)] [AVIC China Precision Engineering Institute for Aircraft Industry, Beijing (China)

2013-09-11

175

Acoustic resonator providing fixed points of temperature between 0.1 and 2 K

NASA Astrophysics Data System (ADS)

Below 2 K the speed of second sound in mixtures of liquid 3He and 4He first increases to a maximum of 30-40 m/s at about 1 K and then decreases again at lower temperatures to values below 15 m/s. The exact values depend on the concentration and pressure of the mixture. This can be exploited to provide fixed points in temperature by utilizing a resonator with appropriate dimensions and frequency to excite standing waves in the resonator cavity filled with helium mixture. We demonstrate that commercially mass produced quartz tuning forks can be used for this purpose. They are meant for frequency standards operating at 32 kHz. Their dimensions are typically of order 1 mm matching the wavelength of the second sound in helium mixtures at certain values of temperature. Due to the complicated geometry, we observe some 20 sharp acoustic resonances in the range 0.1ell 2 K having temperature resolution of order 1 ?K. The quartz resonators are cheap, compact, simple to implement, easy to measure with great accuracy, and, above all, they are not sensitive to magnetic field, which is a great advantage compared to fixed point devices based on superconductivity transitions. The reproducibility of the resonance pattern upon thermal cycling remains to be verified.

Salmela, Anssi; Tuoriniemi, Juha; Pentti, Elias; Sebedash, Alexander; Rysti, Juho

2009-02-01

176

Distribution of fixed-point energies of a quasiperiodic Hamiltonian flow.

Energy distributions rho(+/-)(E) for the elliptic and hyperbolic fixed points of the Hamiltonian H(x,y)= summation operator (k=0) (4) cos [x cos(2pik/5)+y sin(2pik/5)] are calculated as integrals over a one-dimensional manifold M(E) in five-dimensional space. Singular points of M(E) produce three logarithmic singularities of rho(+/-)(E), and vanishing of connected components of M(E) gives rise to three discontinuities. The strengths of the singularities and discontinuities of rho(+/-)(E) are determined analytically, and the distributions are evaluated numerically for representative points in the nonsingular intervals. The calculation provides an explicit realization of general theorems concerning the critical points of infinitely smooth functions defined on an n-dimensional torus and restricted to a k-dimensional linear subset. Formally the calculation resembles the determination of the density of states of a dynamical system with one degree of freedom on a 2-torus, but with important differences due to topology and symmetry. PMID:12780115

Lowenstein, J. H.

1994-06-01

177

NASA Astrophysics Data System (ADS)

Ambiguity resolution (AR) for a single receiver has been a popular topic in Global Positioning System (GPS) recently. Ambiguity-resolution methods for precise point positioning (PPP) have been well documented in recent years, demonstrating that it can improve the accuracy of PPP. However, users are often concerned about the reliability of ambiguity-fixed PPP solution in practical applications. If ambiguities are fixed to wrong integers, large errors would be introduced into position estimates. In this paper, we aim to assess the correct fixing rate (CFR), i.e., number of ambiguities correctly fixing to the total number of ambiguities correctly and incorrectly fixing, for PPP user ambiguity resolution on a global scale. A practical procedure is presented to evaluate the CFR of PPP user ambiguity resolution. GPS data of the first 3 days in each month of 2010 from about 390 IGS stations are used for experiments. Firstly, we use GPS data collected from about 320 IGS stations to estimate global single-differenced (SD) wide-lane and narrow-lane satellite uncalibrated phase delays (UPDs). The quality of UPDs is evaluated. We found that wide-lane UPD estimates have a rather small standard deviation (Std) between 0.003 and 0.004 cycles while most of Std of narrow-lane estimates are from 0.01 to 0.02 cycles. Secondly, many experiments have been conducted to investigate the CFR of integer ambiguity resolution we can achieve under different conditions, including reference station density, observation session length and the ionospheric activity. The results show that the CFR of PPP can exceed 98.0 % with only 1 h of observations for most user stations. No obvious correlation between the CFR and the reference station density is found. Therefore, nearly homogeneous CFR can be achieved in PPP AR for global users. At user end, higher CFR could be achieved with longer observations. The average CFR for 30-min, 1-h, 2-h and 4-h observation is 92.3, 98.2, 99.5 and 99.7 %, respectively. In order to get acceptable CFR, 1 h is a recommended minimum observation time. Furthermore, the CFR of PPP can be affected by diurnal variation and geomagnetic latitude variation in the ionosphere. During one day at the hours when rapid ionospheric variations occur or in low geomagnetic latitude regions where equatorial electron density irregularities are produced relatively frequently, a significant degradation of the CFR is demonstrated.

Zhang, Xiaohong; Li, Pan

2013-06-01

178

\\u000a The first aim of this paper is to present a useful toolbox of quasi-nonexpansive mappings for convex optimization from the\\u000a viewpoint of using their fixed point sets as constraints. Many convex optimization problems have been solved through elegant\\u000a translations into fixed point problems. The underlying principle is to operate a certain quasi-nonexpansive mapping T iteratively and generate a convergent sequence

Isao Yamada; Masahiro Yukawa; Masao Yamagishi

179

Fixed-point rubbing fault characteristic analysis of a rotor system based on contact theory

NASA Astrophysics Data System (ADS)

In this paper, fault characteristics of a single span rotor system with two discs are investigated when the rubbing between a disc and an elastic rod (a fixed limiter) occurs. First, a finite element (FE) model of the rotor system is developed, a point-point contact model is established to simulate the rotor-stator rubbing by simplifying the disc and the rod as two contact points, and then the two models are coupled by contact force. In addition, the augmented Lagrangian method is applied to deal with contact constraint conditions and the coulomb friction model is used to simulate rotor-stator frictional characteristics. The vibration features of the rotor system with rubbing are analyzed with respect to the effects of the gaps between the disc and the rod, the contact stiffnesses under three typical cases with different rotating speeds. The simulation results show that different rotor motions appear, such as period-one motion (P1), P2 and P3 with the increasing rotating speeds, which are in agreement with the experimental measurements. Besides, the gap between the disc and the rod as well as the contact stiffness has a main influence on the vibration intensity and collision rebound forms.

Ma, Hui; Shi, Chaoyang; Han, Qingkai; Wen, Bangchun

2013-07-01

180

Progress report for the CCT-WG5 high temperature fixed point research plan

An overview of the progress in High Temperature Fixed Point (HTFP) research conducted under the auspices of the CCT-WG5 research plan is reported. In brief highlights are: Provisional long term stability of HTFPs has been demonstrated. Optimum construction methods for HTFPs have been established and high quality HTFPs of Co-C, Pt-C and Re-C have been constructed for thermodynamic temperature assignment. The major sources of uncertainty in the assignment of thermodynamic temperature have been identified and quantified. The status of absolute radiometric temperature measurement has been quantified through the circulation of a set of HTFPs. The measurement campaign to assign low uncertainty thermodynamic temperatures to a selected set of HTFPs will begin in mid-2012. It is envisaged that this will be complete by 2015 leading to HTFPs becoming routine reference standards for radiometry and high temperature metrology.

Machin, G.; Woolliams, E. R. [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex,TW11 0LW (United Kingdom)] [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex,TW11 0LW (United Kingdom); Anhalt, K. [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin (Germany)] [Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, 10587 Berlin (Germany); Bloembergen, P. [National Institute of Metrology (NIM), Bei San Huan Dong Lu No. 18, Beijing, 100013 (China)] [National Institute of Metrology (NIM), Bei San Huan Dong Lu No. 18, Beijing, 100013 (China); Sadli, M. [Laboratoire Commun de Métrologie (LNE-Cnam), 61, rue du Landy, 93210 Saint-Denis, La Plaine (France)] [Laboratoire Commun de Métrologie (LNE-Cnam), 61, rue du Landy, 93210 Saint-Denis, La Plaine (France); Yamada, Y. [National Measurement Institute of Japan (NMIJ), AIST, Tsukuba, Ibaraki (Japan)] [National Measurement Institute of Japan (NMIJ), AIST, Tsukuba, Ibaraki (Japan)

2013-09-11

181

NASA Astrophysics Data System (ADS)

We develop a general procedure that allows the determination of the spectral transmittance and reflectance at normal incidence for arbitrary one-dimensional continuous materials as well as the analysis of the time-domain propagation of pulses through them. This procedure consists of a generalization of Fresnel equations, and it is supported by an iterative algorithm also developed here: the polynomial fixed-point algorithm (PFPA). We apply these theoretical results to some concrete examples, such as determining the transmittance and reflectance for an absorptionless photonic crystal, an optical rugate filter, and a photonic crystal with periodic absorption. We also analyze the time-domain propagation of ultrashort Gaussian pulses through different structures.

Perez-Molina, M.; Carretero-Lopez, Luis

2007-06-01

182

NASA Astrophysics Data System (ADS)

The fixed-point theory is first used to consider the stability for stochastic partial differential equations with delays. Some conditions for the exponential stability in pth mean as well as in sample path of mild solutions are given. These conditions do not require the monotone decreasing behavior of the delays, which is necessary in [T. Caraballo, K. Liu, Exponential stability of mild solutions of stochastic partial differential equations with delays, Stoch. Anal. Appl. 17 (1999) 743-763; Ruhollan Jahanipur, Stability of stochastic delay evolution equations with monotone nonlinearity, Stoch. Anal. Appl. 21 (2003) 161-181]. Even in this special case, our results also improve the results in [T. Caraballo, K. Liu, Exponential stability of mild solutions of stochastic partial differential equations with delays, Stoch. Anal. Appl. 17 (1999) 743-763].

Luo, Jiaowan

2008-06-01

183

Progress report for the CCT-WG5 high temperature fixed point research plan

NASA Astrophysics Data System (ADS)

An overview of the progress in High Temperature Fixed Point (HTFP) research conducted under the auspices of the CCT-WG5 research plan is reported. In brief highlights are: Provisional long term stability of HTFPs has been demonstrated. Optimum construction methods for HTFPs have been established and high quality HTFPs of Co-C, Pt-C and Re-C have been constructed for thermodynamic temperature assignment. The major sources of uncertainty in the assignment of thermodynamic temperature have been identified and quantified. The status of absolute radiometric temperature measurement has been quantified through the circulation of a set of HTFPs. The measurement campaign to assign low uncertainty thermodynamic temperatures to a selected set of HTFPs will begin in mid-2012. It is envisaged that this will be complete by 2015 leading to HTFPs becoming routine reference standards for radiometry and high temperature metrology.

Machin, G.; Anhalt, K.; Bloembergen, P.; Sadli, M.; Yamada, Y.; Woolliams, E. R.

2013-09-01

184

NASA Astrophysics Data System (ADS)

This paper reports thermal modelling that aims to establish if the measurement method - either by a radiation thermometer or by a thermocouple - significantly influences the measured temperature of the high temperature fixed points Co-C, Pd-C and Ru-C. It is clear that both measurement techniques have specific physical characteristics which may affect the temperature measured during the melting plateau. With the radiation thermometer, the radiation heat transfer is directly influenced by the environment because the back-wall is effectively viewing the cold outside environment. In the case of a thermocouple direct viewing of the outside world is blocked so radiation transport is significantly reduced; however, in the case of the thermocouple there is a different component of heat transfer, namely conduction from the thermowell walls in contact with the thermocouple along the thermocouple stem itself.

Castro, P.; Machin, G.; Pearce, J. V.

2013-09-01

185

NASA Technical Reports Server (NTRS)

Results are presented from temporally dense measurements of crustal deformation associated with the convergence of the Eurasian (EUR), Pacific, North American, and Philippine Sea (PHS) plates, carried out in April 1988 by a 10-station GPS fixed-point network established in central Japan. Using regional orbit relaxation methods, the analysis of the first 17-month data revealed significant horizontal deformation across the Suruga trough. Namely, it was found that a site in the northern tip of PHS plate moved nearly westward with a velocity of 28 +/-5 mm per year, and a site at the southeastern tip of EUR plate moved south-southwestward with a velocity of 18 +/-5 mm per year. A significant vertical uplift with a velocity of 20 mm/yr was detected at a site inland of the Tokai district located in the Akaishi uplift zone and at a site on the Hatsushima Island in Sagami Bay.

Shimada, Seiichi; Bock, Yehuda

1992-01-01

186

NASA Astrophysics Data System (ADS)

We explore the nonperturbative renormalization group flow of quantum Einstein gravity (QEG) on an infinite dimensional theory space. We consider “conformally reduced” gravity where only fluctuations of the conformal factor are quantized and employ the local potential approximation for its effective average action. The requirement of “background independence” in quantum gravity entails a partial differential equation governing the scale dependence of the potential for the conformal factor which differs significantly from that of a scalar matter field. In the infinite dimensional space of potential functions we find a Gaussian as well as a non-Gaussian fixed point which provides further evidence for the viability of the asymptotic safety scenario. The analog of the invariant cubic in the curvature which spoils perturbative renormalizability is seen to be unproblematic for the asymptotic safety of the conformally reduced theory. The scaling fields and dimensions of both fixed points are obtained explicitly and possible implications for the predictivity of the theory are discussed. Spacetime manifolds with Rd as well as Sd topology are considered. Solving the flow equation for the potential numerically we obtain examples of renormalization group trajectories inside the ultraviolet critical surface of the non-Gaussian fixed point. The quantum theories based upon some of them show a phase transition from the familiar (low energy) phase of gravity with spontaneously broken diffeomorphism invariance to a new phase of unbroken diffeomorphism invariance; the latter phase is characterized by a vanishing expectation value of the metric.

Reuter, M.; Weyer, H.

2009-07-01

187

Assessment of tungsten/rhenium thermocouples with metal-carbon eutectic fixed points up to 1500°C

Four Type A thermocouples and two Type C thermocouples were calibrated at the Au fixed point and Co-C and Pd-C eutectic fixed points. The thermocouples were exposed to 1330 °C for a total of 100 hours. The maximum drift due to the exposure was found to be 4.8 °C. The fixed-point calibration EMF of these thermocouples deviated by less than 0.86% from the temperature specified by the standards ASTM E230-2003 for Type C and GOSTR 8.585-2001 for Type A. The length of one of Type A thermocouples A52 is longer than the others by 150mm. Making use of this provision it was possible to place annealed part of A52 to the temperature gradient part of calibration arrangement every time. Therefore observed aging effect was as low as 0.5 °C compared to the other thermocouples.

Gotoh, M. [National Research Council of Canada 1200 Montreal Road, Ottawa ON. Canada K1A 0R6 (Canada)] [National Research Council of Canada 1200 Montreal Road, Ottawa ON. Canada K1A 0R6 (Canada)

2013-09-11

188

NASA Astrophysics Data System (ADS)

This publication deals with the practical challenge of describing the impurity influence on the fixed-point temperature of zinc. For this, the sum of individual estimate (SIE) approach is applied to miniaturized fixed-point cells (MFPC) filled with high-purity zinc that can be used in industrial applications. This includes comparative analyses by glow discharge mass spectroscopy as well as mass spectroscopy with inductive coupled plasma to quantify the impurity concentrations in zinc. Furthermore, the element-specific and concentration-dependent temperature deviations are presented for the fixed-point material zinc. For this, binary phase diagrams as well as thermal calculations and experimental data were analysed to extract the relevant sensitivity coefficients. Besides, results from SIE analyses of MFPCs are presented and their uncertainties are compared. On this basis, practical limits of the SIE method are identified and discussed.

Krapf, G.; Mammen, H.; Blumröder, G.; Fröhlich, T.

2012-07-01

189

In this paper, we describe an InGaAs detector based radiation thermometer (IRT) and new design of fixed-point blackbodies, including Sn, Zn, Al and Cu, for the establishment of a temperature scale from 200 °C to 1085 °C at the National Institute of Metrology of China. The construction and calibration of the IRT with the four fixed-point blackbodies are described. Characteristics of the IRT, such as the size-of-source effect, the amplifier performance and its stability are determined. The design of the four fixed-points, with 10 mm diameter of aperture and 0.9999 emissivity, is described. The uncertainty of the scale realization is elaborated.

Hao, X.; Yuan, Z.; Wang, J.; Lu, X. [Division of Thermometry and Materials Evaluation, National Institute of Metrology, Beijing, China, 100013 (China)] [Division of Thermometry and Materials Evaluation, National Institute of Metrology, Beijing, China, 100013 (China)

2013-09-11

190

NASA Astrophysics Data System (ADS)

In this paper, we describe an InGaAs detector based radiation thermometer (IRT) and new design of fixed-point blackbodies, including Sn, Zn, Al and Cu, for the establishment of a temperature scale from 200 °C to 1085 °C at the National Institute of Metrology of China. The construction and calibration of the IRT with the four fixed-point blackbodies are described. Characteristics of the IRT, such as the size-of-source effect, the amplifier performance and its stability are determined. The design of the four fixed-points, with 10 mm diameter of aperture and 0.9999 emissivity, is described. The uncertainty of the scale realization is elaborated.

Hao, X.; Yuan, Z.; Wang, J.; Lu, X.

2013-09-01

191

NASA Astrophysics Data System (ADS)

Miniature temperature fixed-point industrial platinum resistance thermometers (IPRTs) have been constructed to investigate the feasibility of a self-testable IPRT integrated with a mercury or indium fixed-point cell. The miniature cell was constructed from stainless steel with a combined small PRT sensor element inside it, and was contained within an IPRT protection tube. The reproducibilities of the freezing and melting temperatures measured using the mercury miniature cell were ±0.08 °C and ±0.63 °C, respectively. In the case of indium, only the melting temperature was taken into account, and its reproducibility was ±0.01 °C. The performance of both miniature fixed-point IPRTs was good enough to keep track of the long-term stability of the IPRTs in the order of 0.1 °C.

Kang, Kee Hoon; Kim, Yong-Gyoo; Gam, Kee Sool; Yang, Inseok

2007-09-01

192

Fixed-point algorithms for constrained ICA and their applications in fMRI data analysis.

Constrained independent component analysis (CICA) eliminates the order ambiguity of standard ICA by incorporating prior information into the learning process to sort the components intrinsically. However, the original CICA (OCICA) and its variants depend on a learning rate, which is not easy to be tuned for various applications. To solve this problem, two learning-rate-free CICA algorithms were derived in this paper using the fixed-point learning concept. A complete stability analysis was provided for the proposed methods, which also made a correction to the stability analysis given to OCICA. Variations for adding constraints either to the components or to the associated time courses were derived too. Using synthetic data, the proposed methods yielded a better stability and a better source separation quality in terms of higher signal-to-noise-ratio and smaller performance index than OCICA. For the artificially generated brain activations, the new CICAs demonstrated a better sensitivity/specificity performance than standard univariate general linear model (GLM) and standard ICA. Original CICA showed a similar sensitivity/specificity gain but failed to converge for several times. Using functional magnetic resonance imaging (fMRI) data acquired with a well-characterized sensorimotor task, the proposed CICAs yielded better sensitivity than OCICA, standard ICA and GLM in all the target functional regions in terms of either higher t values or larger suprathreshold cluster extensions using the same significance threshold. In addition, they were more stable than OCICA and standard ICA for analyzing the sensorimotor fMRI data. PMID:21908126

Wang, Ze

2011-11-01

193

Motivated by recent discussions of the string-theory landscape, we propose field-theoretic realizations of models with large numbers of vacua. These models contain multiple U(1) gauge groups, and can be interpreted as deconstructed versions of higher-dimensional gauge theory models with fluxes in the compact space. We find that the vacuum structure of these models is very rich, defined by parameter-space regions with different classes of stable vacua separated by boundaries. This allows us to explicitly calculate physical quantities such as the supersymmetry-breaking scale, the presence or absence of R-symmetries, and probabilities of stable versus unstable vacua. Furthermore, we find that this landscape picture evolves with energy, allowing vacua to undergo phase transitions as they cross the boundaries between different regions in the landscape. Surprisingly, we show that this landscape flow approaches an infrared fixed point, suggesting that it may not be necessary to determine all of the parameters of the ultraviolet theory in order to deduce relevant features of the low-energy phenomenology.

Dienes, Keith R. [Department of Physics, University of Arizona, Tucson, AZ 85721 (United States); Dudas, Emilian [Centre de Physique Theorique, Ecole Polytechnique, F-91128, Palaiseau Cedex (France); LPT, Bat. 210, Univ. Paris-Sud, F-91405, Orsay Cedex (France); Gherghetta, Tony [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

2005-12-02

194

Realization of the WC-C peritectic fixed point at NIM and NMIJ

Three WC-C peritectic fixed point cells, constructed from different sources of tungsten with different nominal purities, were measured at NIM and NMIJ. The three cells were constructed at NMIJ by NIM and NMIJ staffs, and T{sub 90} values of the three cells were measured at NMIJ during the period 31 Aug. to 25 Dec. 2009. Thereafter, the three cells were then transported to NIM, and T{sub 90} values of these cells were measured from 7 Dec. 2011 to 9 Jan. 2012. The results showed that T{sub 90} values of the three cells measured at the two institutes agreed within 0.4 °C with the combined scale comparison uncertainty of 1.7 °C (k= 2). The main component of the uncertainty is not the uncertainty due to impurities of the cells but the scale uncertainty and the stability of the measurement system. From these results it can be concluded that the WC-C cell is stable enough to provide new means of international high-temperature scale comparison above 3000 K.

Wang, T.; Bai, C.; Yuan, Z.; Dong, W.; Lu, X. [National Institute of Metrology (NIM), Beijing (China)] [National Institute of Metrology (NIM), Beijing (China); Sasajima, N.; Yamada, Y.; Ara, C. [National Metrology Institute of Japan, AIST (NMIJ, AIST), Tsukuba (Japan)] [National Metrology Institute of Japan, AIST (NMIJ, AIST), Tsukuba (Japan)

2013-09-11

195

NASA Astrophysics Data System (ADS)

In the modern world of automation, biological signals, especially Electroencephalogram (EEG) and Electrocardiogram (ECG), are gaining wide attention as a source of biometric information. Earlier studies have shown that EEG and ECG show versatility with individuals and every individual has distinct EEG and ECG spectrum. EEG (which can be recorded from the scalp due to the effect of millions of neurons) may contain noise signals such as eye blink, eye movement, muscular movement, line noise, etc. Similarly, ECG may contain artifact like line noise, tremor artifacts, baseline wandering, etc. These noise signals are required to be separated from the EEG and ECG signals to obtain the accurate results. This paper proposes a technique for the removal of eye blink artifact from EEG and ECG signal using fixed point or FastICA algorithm of Independent Component Analysis (ICA). For validation, FastICA algorithm has been applied to synthetic signal prepared by adding random noise to the Electrocardiogram (ECG) signal. FastICA algorithm separates the signal into two independent components, i.e. ECG pure and artifact signal. Similarly, the same algorithm has been applied to remove the artifacts (Electrooculogram or eye blink) from the EEG signal.

Mishra, Puneet; Singla, Sunil Kumar

2013-01-01

196

Fixed-point Algorithms for Constrained ICA and their Applications in fMRI Data Analysis

Constrained independent component analysis (CICA) eliminates the order ambiguity of standard ICA by incorporating prior information into the learning process to sort the components intrinsically. However, the original CICA (OCICA) and its variants depend on a learning rate, which is not easy to be tuned for various applications. To solve this problem, two learning-rate free CICA algorithms were derived in this paper using the fixed-point learning concept. A complete stability analysis was provided for the proposed methods, which also made a correction to the stability analysis given to OCICA. Variations for adding constraints either to the components or the associated time courses were derived too. Using synthetic data, the proposed methods yielded a better stability and a better source separation quality in terms of higher SNR and smaller performance index (PI) than OCICA. For the artificially generated brain activations, the new CICAs demonstrated a better sensitivity/specificity performance than standard univariate general linear model (GLM) and standard ICA. OCICA showed a similar sensitivity/specficity gain but failed to converge for several times. Using fMRI data acquired with a well-characterized sensorimotor task, the proposed CICAs yielded better sensitivity than OCICA, standard ICA, and GLM in all the target functional regions in terms of either higher t-values or larger suprathreshold cluster extensions using the same significance threshold. In addition, they were more stable than OCICA and standard ICA for analyzing the sensorimotor fMRI data.

Wang, Ze

2011-01-01

197

Realization of the WC-C peritectic fixed point at NIM and NMIJ

NASA Astrophysics Data System (ADS)

Three WC-C peritectic fixed point cells, constructed from different sources of tungsten with different nominal purities, were measured at NIM and NMIJ. The three cells were constructed at NMIJ by NIM and NMIJ staffs, and T90 values of the three cells were measured at NMIJ during the period 31 Aug. to 25 Dec. 2009. Thereafter, the three cells were then transported to NIM, and T90 values of these cells were measured from 7 Dec. 2011 to 9 Jan. 2012. The results showed that T90 values of the three cells measured at the two institutes agreed within 0.4 °C with the combined scale comparison uncertainty of 1.7 °C (k = 2). The main component of the uncertainty is not the uncertainty due to impurities of the cells but the scale uncertainty and the stability of the measurement system. From these results it can be concluded that the WC-C cell is stable enough to provide new means of international high-temperature scale comparison above 3000 K.

Wang, T.; Sasajima, N.; Yamada, Y.; Bai, C.; Yuan, Z.; Dong, W.; Ara, C.; Lu, X.

2013-09-01

198

3D transient fixed point mesh adaptation for time-dependent problems: Application to CFD simulations

NASA Astrophysics Data System (ADS)

This paper deals with the adaptation of unstructured meshes in three dimensions for transient problems with an emphasis on CFD simulations. The classical mesh adaptation scheme appears inappropriate when dealing with such problems. Hence, another approach based on a new mesh adaptation algorithm and a metric intersection in time procedure, suitable for capturing and track such phenomena, is proposed. More precisely, the classical approach is generalized by inserting a new specific loop in the main adaptation loop in order to solve a transient fixed point problem for the mesh-solution couple. To perform the anisotropic metric intersection operation, we apply the simultaneous reduction of the corresponding quadratic form. Regarding the adaptation scheme, an anisotropic geometric error estimate based on a bound of the interpolation error is proposed. The resulting computational metric is then defined using the Hessian of the solution. The mesh adaptation stage (surface and volume) is based on the generation, by global remeshing, of a unit mesh with respect to the prescribed metric. A 2D model problem is used to illustrate the difficulties encountered. Then, 2D and 3D complexes and representative examples are presented to demonstrate the efficiency of this method.

Alauzet, F.; Frey, P. J.; George, P. L.; Mohammadi, B.

2007-03-01

199

Supersymmetric renormalisation group fixed points and third generation fermion mass predictions

We present a supersymmetric renormalization group fixed point determination of the third generation fermion masses, in which the large mass ratio between the top and bottom quarks is attributed to a hierarchy in the vacuum expectation values of the two Higgs doublets. Above a supersymmetry breaking scale, M{sub s}, we use the minimal supersymmetric standard model with a transition at M{sub s} to the standard model with only one Higgs- doublet effective. The mass predictions result from renormalization group evolution of large Yukawa couplings at M{sub x} {approximately} 1016 GeV. Averaging over a wide range of these couplings, not subject to any symmetry requirements, gives m{sub t} = 184.3{plus_minus}6.8 GeV, m{sub b} = 4.07{plus_minus}0.33 GeV, m{sub {tau}} = 1.78{plus_minus}0.33 GeV and a light Higgs mass m{sub h}o = 121.8{plus_minus}4.3 GeV for M{sub s} = 1 TeV and {alpha}{sub s} (M{sub z}) = 0.125.

Froggatt, C.D.; Moorhouse, R.G. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Knowles, I.G. [Argonne National Lab., IL (United States)

1992-09-01

200

A configurable floating-point coprocessor by a FPGA is designed to enhance the computational capability of the digital platform based on the fixed-point DSP, with which the platform will be competent to implement intensively computational tasks. Detailed design procedures of the coprocessor are presented. A new division algorithm is proposed by combining the lookup-table algorithm and multiplicative algorithm in order to

Haibing Hu; Tianjun Jin; Xianmiao Zhang; Zhengyu Lu; Zhaoming Qian

2006-01-01

201

Analysis of gene network robustness based on saturated fixed point attractors.

The analysis of gene network robustness to noise and mutation is important for fundamental and practical reasons. Robustness refers to the stability of the equilibrium expression state of a gene network to variations of the initial expression state and network topology. Numerical simulation of these variations is commonly used for the assessment of robustness. Since there exists a great number of possible gene network topologies and initial states, even millions of simulations may be still too small to give reliable results. When the initial and equilibrium expression states are restricted to being saturated (i.e., their elements can only take values 1 or -1 corresponding to maximum activation and maximum repression of genes), an analytical gene network robustness assessment is possible. We present this analytical treatment based on determination of the saturated fixed point attractors for sigmoidal function models. The analysis can determine (a) for a given network, which and how many saturated equilibrium states exist and which and how many saturated initial states converge to each of these saturated equilibrium states and (b) for a given saturated equilibrium state or a given pair of saturated equilibrium and initial states, which and how many gene networks, referred to as viable, share this saturated equilibrium state or the pair of saturated equilibrium and initial states. We also show that the viable networks sharing a given saturated equilibrium state must follow certain patterns. These capabilities of the analytical treatment make it possible to properly define and accurately determine robustness to noise and mutation for gene networks. Previous network research conclusions drawn from performing millions of simulations follow directly from the results of our analytical treatment. Furthermore, the analytical results provide criteria for the identification of model validity and suggest modified models of gene network dynamics. The yeast cell-cycle network is used as an illustration of the practical application of this analytical treatment. PMID:24650364

Li, Genyuan; Rabitz, Herschel

2014-01-01

202

Analysis of gene network robustness based on saturated fixed point attractors

The analysis of gene network robustness to noise and mutation is important for fundamental and practical reasons. Robustness refers to the stability of the equilibrium expression state of a gene network to variations of the initial expression state and network topology. Numerical simulation of these variations is commonly used for the assessment of robustness. Since there exists a great number of possible gene network topologies and initial states, even millions of simulations may be still too small to give reliable results. When the initial and equilibrium expression states are restricted to being saturated (i.e., their elements can only take values 1 or ?1 corresponding to maximum activation and maximum repression of genes), an analytical gene network robustness assessment is possible. We present this analytical treatment based on determination of the saturated fixed point attractors for sigmoidal function models. The analysis can determine (a) for a given network, which and how many saturated equilibrium states exist and which and how many saturated initial states converge to each of these saturated equilibrium states and (b) for a given saturated equilibrium state or a given pair of saturated equilibrium and initial states, which and how many gene networks, referred to as viable, share this saturated equilibrium state or the pair of saturated equilibrium and initial states. We also show that the viable networks sharing a given saturated equilibrium state must follow certain patterns. These capabilities of the analytical treatment make it possible to properly define and accurately determine robustness to noise and mutation for gene networks. Previous network research conclusions drawn from performing millions of simulations follow directly from the results of our analytical treatment. Furthermore, the analytical results provide criteria for the identification of model validity and suggest modified models of gene network dynamics. The yeast cell-cycle network is used as an illustration of the practical application of this analytical treatment.

2014-01-01

203

NASA Astrophysics Data System (ADS)

We obtain a common fixed point for two pairs of self-maps on a complete metric space, one of which is reciprocally continuous and compatible, while the other weakly compatible, where all the four maps satisfy a generalized inequality. Our result is a significant generalization of that of Singh and Mishra.

Phaneendra, T.; Swatmaram

2012-10-01

204

NASA Astrophysics Data System (ADS)

we give some new fixed point theorems for semi-closed 1-set-contractive operators and apply He's variational iteration method to solve some integral equations (see [3]). We extend some conclusion and these methods are important meanings which are different from the recent works.

Chen, Ning; Tian, Baodan; Chen, Jiqian

205

We present a fixed-point iterative method for solving systems of nonlinear equations. The convergence theorem of the proposed method is proved under suitable conditions. In addition, some numerical results are also reported in the paper, which confirm the good theoretical properties of our approach.

Huang, Na

2014-01-01

206

A lumped model of neural activity in neocortex is studied to identify regions of multi-stability of both steady states and periodic solutions. Presence of both steady states and periodic solutions is considered to correspond with epileptogenesis. The model, which consists of two delay differential equations with two fixed time lags is mainly studied for its dependency on varying connection strength between populations. Equilibria are identified, and using linear stability analysis, all transitions are determined under which both trivial and non-trivial fixed points lose stability. Periodic solutions arising at some of these bifurcations are numerically studied with a two-parameter bifurcation analysis.

2012-01-01

207

APPROACHING THE TIPPING POINT CLIMATE RISKS, FAITH AND POLITICAL ACTION

Scientific and media reports have become enthralled by the apocalyptic overtones of climatic 'tipping points'. These are thresholds after which a relatively small shift in the Earth system (e.g. melting Arctic perma-frost) has a big, sudden impact on the overall system. Related is the prospect of runaway or 'irreversible' global warming. But it has also revived an interest in its

Stefan Skrimshire

2008-01-01

208

Preliminary sketch of possible Fixed Point transformations for use in adaptive control

In this paper a further step towards a novel approach to adaptive nonlinear control developed at Budapest Tech in the past few years is reported. Its main advantage in comparison with the complicated Lyapunov function based techniques is that it is based on simple geometric considerations on the basis of which the control task can be formulated as a fixed

J. K. Tar; J. F. Bito; L. Nadai; J. A. T. Machado

2008-01-01

209

NASA Astrophysics Data System (ADS)

The results of LO fixed point QCD (FP-QCD) analysis of the CCFR data for the nucleon structure function xF3(x, Q2) are presented. The predictions of FP-QCD, in which the Callan—Symanzik ?-function admits a second-order ultraviolet zero at ?=?0 are in good agreement with the data. Constraints for the possible values of the ?-function parameter b regulating how fast ?s(Q2) tends to its asymptotic value ?0?0 are found from the data. The corresponding values of ?0 are also determined. Having in mind our recent “first-order fixed point” QCD fit to the same data we conclude that despite the high precision and the large (x, Q2) kinematic range of the CCFR data they cannot discriminate between QCD and FP-QCD predictions for xF3(x, Q2).

Sidorov, Aleksander V.; Stamenov, Dimiter B.

210

Effect of intravenous ketanserin on the human action potential duration at fixed heart rate

In this study any changes in action potential duration or Q-T interval due to acute doses of ketanserin were monitored. The effect of a bolus dose (10 or 20 mg) followed by an infusion (10 or 20 mg over 20 minutes) of ketanserin on the Q-T interval and action potential duration was studied in six patients undergoing routine cardiac catheterization.

Angela J. Drake-Holland; Mark I. M. Noble; Sara Pugh; Christopher Mills

1988-01-01

211

A vertical cobalt-carbon (Co-C) eutectic fixed point cell was constructed at PTB to demonstrate its use for improvement of the calibration of noble-metal thermocouples at temperatures above 1100 °C. The melting and freezing temperatures of the Co-C eutectic were measured in different high-temperature furnaces at PTB and INMETRO (Brazil) to show its stability by using a Pt\\/Pd thermocouple. The reproducibility

F. Edler; A. C. Baratto

2005-01-01

212

Influence of the Opening of a Blackbody Cavity Measured at the Ag and Cu ITS-90 Fixed Points

NASA Astrophysics Data System (ADS)

The International Temperature Scale of 1990 blackbody fixed points are commonly composed of a graphite crucible containing a pure metal enclosing a radiating blackbody cavity. The shape of the cavity is determined to behave as much as possible as a perfect blackbody; however, the opening from which the radiance is measured induces radiative losses. The measured temperature is therefore underestimated by a few tens of millikelvins at 1000°C, compared to that of a perfect blackbody. The difference is due, on the one hand, to the drop of emissivity caused by the opening, and on the other hand, to the temperature drop between the solid/liquid interface and the inner wall of the cavity, observed by the radiation thermometer. The temperature drop is generally estimated by modeling the emissivity and the temperature difference across the cavity wall. This approach is relevant as long as the temperature distribution along the cavity and the graphite properties are known, but in many cases, the lack of data does not allow precise determination of the corrections. The corrections for the temperature drop and emissivity drop, which both depend on the cavity opening, can be determined experimentally with a low uncertainty by measuring the temperature of a fixed point for different cavity openings. To be significant, the measurement requires a source stable within a few millikelvins. In this study, this constraint has been solved by changing the cavity opening during the phase transition of the fixed point, with a rotating wheel supporting apertures of different dimensions. Measurements have been performed at the Ag and Cu fixed points during the freezing plateaus. Experimental results are presented and compared to those obtained by modeling.

Bourson, F.; Sadli, M.; Rougié, B.; Briaudeau, S.; Kozlova, O.

2014-05-01

213

This paper is devoted to study the existence of periodic solutions of the second-order equation x?=f(t,x), where f is a Carathéodory function, by combining some new properties of Green's function together with Krasnoselskii fixed point theorem on compression and expansion of cones. As applications, we get new existence results for equations with jumping nonlinearities as well as equations with a

Pedro J. Torres

2003-01-01

214

Small copper fixed-point cells of the hybrid type to be used in place of normal larger cells

NASA Astrophysics Data System (ADS)

Two small cells for the realization of the fixed point of copper were constructed and investigated at INRIM. They are of the same hybrid design generally adopted for the eutectic high-temperature fixed-point cells, namely a structure with a sacrificial graphite sleeve and a layer of flexible carbon-carbon composite sheet (C/C sheet). Because of the largely different design with respect to the cells normally adopted for the construction of pure metal fixed points, they were compared and characterized with respect to the normal cells used at INRIM for the ITS-90 realization. Two different furnaces were used to compare hybrid and normal cells. One of the hybrid cells was also used in different configurations, i.e. without the C/C sheet and with two layers of sheet. The cells were compared with different operative conditions, i.e. temperature settings of the furnaces for inducing the freeze, and repeatability and reproducibility were investigated. Freezing temperature and shape of the plateaux obtained under the different conditions were analysed. As expected the duration of the plateaux obtained with the hybrid cells is considerably shorter than with the normal cell, but this does not affect the results in terms of freezing temperature. Measurements with the modified cell showed that the use of a double C/C sheet may improve both repeatability and reproducibility of the plateaux.

Battuello, M.; Girard, F.; Florio, M.

2012-10-01

215

Using integrated miniature fixed-point cells, a measuring uncertainty of < 1 K can be reached under operat- ing condi tions in the superheated steam range of power plants by a periodic recalibration of the thermocouples, with operating times of > 20000 h. The fixed-point materials used for a temperature range from 500 o C to 650 o C are techni-

Frank Bernhard; Dirk Boguhn; Silke Augustin; Helge Mammen; Andrej Donin

2003-01-01

216

The EuroSITES network: Integrating and enhancing fixed-point open ocean observatories around Europe

NASA Astrophysics Data System (ADS)

EuroSITES is a 3 year (2008-2011) EU collaborative project (3.5MEuro) with the objective to integrate and enhance the nine existing open ocean fixed point observatories around Europe (www.eurosites.info). These observatories are primarily composed of full depth moorings and make multidisciplinary in situ observations within the water column as the European contribution to the global array OceanSITES (www.oceansites.org). In the first 18 months, all 9 observatories have been active and integration has been significant through the maintenance and enhancement of observatory hardware. Highlights include the enhancement of observatories with sensors to measure O2, pCO2, chlorophyll, and nitrate in near real-time from the upper 1000 m. In addition, some seafloor missions are also actively supported. These include seafloor platforms currently deployed in the Mediterranean, one for tsunami detection and one to monitor fluid flow related to seismic activity and slope stability. Upcoming seafloor science missions in 2010 include monitoring benthic biological communities and associated biogeochemistry as indicators of climate change in both the Northeast Atlantic and Mediterranean. EuroSITES also promotes the development of innovative sensors and samplers in order to progress capability to measure climate-relevant properties of the ocean. These include further developing current technologies for autonomous long-term monitoring of oxygen consumption in the mesopelagic, pH and mesozooplankton abundance. Many of these science missions are directly related to complementary activities in other European projects such as EPOCA, HYPOX and ESONET. In 2010 a direct collaboration including in situ field work will take place between ESONET and EuroSITES. The demonstration mission MODOO (funded by ESONET) will be implemented in 2010 at the EuroSITES PAP observatory. Field work will include deployment of a seafloor lander system with various sensors which will send data to shore in real time via the EuroSITES water column infrastructure. EuroSITES Data management is led by NOCS, UK with CORIOLIS, France as one of the Global Data assembly centre (GDAC) for both EuroSITES and OceanSITES. EuroSITES maintains the OceanSITES and GEO philosophy of open access to data in near real-time. With a common data policy and standardised data formats (OceanSITES NetCDF) EuroSITES is increasing the potential users of in situ ocean datasets and the societal benefit of these data. For instance, CORIOLIS is central to the ever increasing contribution of EuroSITES as an upstream data provider to the GMES project MyOcean (both real-time and delayed-mode data). Outreach and knowledge transfer of EuroSITES activities and results are also a key component to the project with a dedicated outreach website, Fact Sheet, cruise diaries and educational tools being developed in the first 18 months. In 2010 a film will be released to represent the network and this will be distributed to a wide audience through the European network of aquaria and at other outreach events. In addition, the EuroSITES project and it's relevance to global ocean observation initiatives continues to be actively promoted at both scientific and non-specialist meetings and events. By the end of EuroSITES in April 2011, the 9 core ocean observatories will be well integrated. Each observatory will have enhanced infrastructure to include both physical and biogeoechemical sensors. Science missions in the ocean interior and seafloor/subseafloor will have progressed European ocean observational capability significantly. Collaborations will have taken place or will be at an advanced stage of planning with related European and international projects including ESONET FP6 NoE and the NSF funded Ocean Observatories Initiative (OOI) (400M over 5 years). EuroSITES will continue to develop it's contribution to the ocean component of the Group on Earth Observations (GEO) through task AR-09-03c 'Global Ocean Observing Systems' and related societal benefit areas.

Lampitt, Richard S.; Larkin, Kate E.; EuroSITES Consortium

2010-05-01

217

This Corrective Action Decision Document (CADD) identifies and rationalizes the U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office's selection of a recommended corrective action alternative appropriate to facilitate the closure of Corrective Action Unit (CAU) 516: Septic Systems and Discharge Points, Nevada Test Site (NTS), Nevada, under the Federal Facility Agreement and Consent Order. Located in Areas 3, 6, and 22 on the NTS, CAU 516 includes six Corrective Action Sites (CASs) consisting of two septic systems, a sump and piping, a clean-out box and piping, dry wells, and a vehicle decontamination area. Corrective action investigation activities were performed from July 22 through August 14, 2003, with supplemental sampling conducted in late 2003 and early 2004. The potential exposure pathways for any contaminants of concern (COCs) identified during the development of the DQOs at CAU 516 gave rise to the following objectives: (1) prevent or mitigate exposure to media containing COCs at concentrations exceeding PALs as defined in the corrective action investigation plan; and (2) prevent the spread of COCs beyond each CAS. The following alternatives have been developed for consideration at CAU 516: Alternative 1 - No Further Action; Alternative 2 - Clean Closure; and Alternative 3 - Closure in Place with Administrative Controls. Alternative 1, No Further Action, is the preferred corrective action for two CASs (06-51-02 and 22-19-04). Alternative 2, Clean Closure, is the preferred corrective action for four CASs (03-59-01, 03-59-02, 06-51-01, and 06-51-03). The selected alternatives were judged to meet all requirements for the technical components evaluated, as well as meeting all applicable state and federal regulations for closure of the site and will further eliminate the contaminated media at CAU 516.

U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office

2004-04-28

218

Two-stage fixed-bed gasifier with selectable middle gas off-take point

A two-stage fixed bed coal gasifier wherein an annular region is in registry with a gasification zone underlying a devolatilization zone for extracting a side stream of high temperature substantially tar-free gas from the gasifier. A vertically displaceable skirt means is positioned within the gasifier to define the lower portion of the annular region so that vertical displacement of the skirt means positions the inlet into the annular region in a selected location within or in close proximity to the gasification zone for providing a positive control over the composition of the side stream gas.

Strickland, Larry D. (Morgantown, WV); Bissett, Larry A. (Morgantown, WV)

1992-01-01

219

We study the Ising model in a hierarchical small-world network by renormalization group analysis and find a phase transition between an ordered phase and a critical phase, which is driven by the coupling strength of the shortcut edges. Unlike ordinary phase transitions, which are related to unstable renormalization fixed points (FPs), the singularity in the ordered phase of the present model is governed by the FP that coincides with the stable FP of the ordered phase. The weak stability of the FP yields peculiar criticalities, including logarithmic behavior. On the other hand, the critical phase is related to a nontrivial FP, which depends on the coupling strength and is continuously connected to the ordered FP at the transition point. We show that this continuity indicates the existence of a finite correlation-length-like quantity inside the critical phase, which diverges upon approaching the transition point. PMID:23030852

Nogawa, Tomoaki; Hasegawa, Takehisa; Nemoto, Koji

2012-09-01

220

NASA Astrophysics Data System (ADS)

In order to improve the performance of precise point positioning (PPP), this paper presents a new data processing scheme to shorten the convergence time and the observation time required for a reliable ambiguity-fixing. In the new scheme, L1 and L2 raw observations are used and the slant ionospheric delays are treated as unknown parameters. The empirical spatial and temporal constraints and the ionospheric delays derived from a real-time available ionospheric model are all considered as pseudo-observations into the estimation for strengthening the solution. Furthermore, we develop a real-time computational procedure for generating uncalibrated phase delays (UPDs) on L1 and L2 frequencies. The PPP solution is first carried out on all reference stations based on the proposed scheme, undifferenced float ambiguities on L1 and L2 frequencies can be directly obtained from the new scheme. The L1 and L2 UPDs are then generated and broadcasted to users in real-time. This data product and also the performance of the new PPP scheme are evaluated. Our results indicate that the new processing scheme considering ionospheric characteristics can reduce the convergence time by about 30 % for float kinematic solutions. The observation time for a reliable ambiguity-fixing is shortened by 25 % compared to that of the traditional ambiguity-fixed kinematic solution. When the new method is used for static reference stations, the observation time for ambiguity-fixing is about 10 min in static mode and only 5 min if the coordinates are fixed to well-known values.

Li, Xingxing; Ge, Maorong; Zhang, Hongping; Wickert, Jens

2013-05-01

221

Routes to chaos in the Hopf-saddle-node bifurcation for fixed points of 3D-diffeomorphisms

NASA Astrophysics Data System (ADS)

Dynamical phenomena are studied near a Hopf-saddle-node bifurcation of fixed points of 3D-diffeomorphisms. The interest lies in the neighbourhood of weak resonances of the complex conjugate eigenvalues. The 1 : 5 case is chosen here because it has the lowest order among the weak resonances, and therefore it is likely to have a most visible influence on the bifurcation diagram. A model map is obtained by a natural construction, through perturbation of the flow of a Poincaré-Takens normal form vector field. Global bifurcations arise in connection with a pair of saddle-focus fixed points: homoclinic tangencies occur near a sphere-like heteroclinic structure formed by the 2D stable and unstable manifolds of the saddle points. Strange attractors occur for nearby parameter values and three routes are described. One route involves a sequence of quasi-periodic period doublings of an invariant circle where loss of reducibility also takes place during the process. A second route involves intermittency due to a quasi-periodic saddle-node bifurcation of an invariant circle. Finally a route involving heteroclinic phenomena is discussed. Multistability occurs in several parameter subdomains: we analyse the structure of the basins for a case of coexistence of a strange and a quasi-periodic attractor and for coexistence of two strange attractors. By construction, the phenomenology of the model map is expected in generic families of 3D diffeomorphisms. In memoriam: Floris Takens.

Vitolo, Renato; Broer, Henk; Simó, Carles

2010-08-01

222

This Corrective Action Decision Document (CADD) has been prepared for Corrective Action Unit (CAU) 423, Building 03-60 Underground Discharge Point (UDP) in accordance with the Federal Facility Agreement and Consent Order (FFACO) of 1996 that was agreed to by the US Department of Energy, Nevada Operations Office (DOE/NV); the Nevada Division of Environmental Protection (NDEP); and the U.S Department of Defense (FFACO, 1996). The CADD provides or references the specific information necessary to recommend a preferred corrective action for the single Corrective Action Site (CAS), 03-02-002-0308, within CAU 423. Corrective Action Unit 423 is located at the Tonopah Test Range (TTR), Nevada. The TTR is approximately 255 kilometers (km) (140 miles[mi]) northwest of Las Vegas, Nevada. The UDP is approximately 73 meters (m) (240 feet [ft]) northwest of the northwest corner of Building 03-60, the Auto Maintenance Shop. Corrective Action Unit 423 is comprised of the UDP and an associated discharge line extending from Building 03-60. The UDP received waste oil products from the Auto Maintenance Shop, a light-duty fleet maintenance shop in the Area 3 compound, from 1965 to 1989 or 1990 (DOE/NV, 1997).

DOE /NV

1999-06-19

223

NASA Astrophysics Data System (ADS)

Of the various types of passive engine mounts, hydraulic engine mounts (HEMs) have the best noise, vibration and harshness (NVH) performance. Based on the third type HEM, which has an inertia track, decoupler and disturbing plate, the influences of the three hydraulic mechanisms, the length of the inertia track or the diameter of the orifice on the dynamic properties were studied experimentally. The working principles of the hydraulic mechanisms and the relationship between the dynamic properties of the three type HEMs were revealed clearly. It was discovered that the frequency-variant dynamic properties of HEMs with an inertia track or an orifice have excitation amplitude-invariant fixed points. Based on the theory of engineering hydromechanics, a nonlinear lumped parameter model (LPM) for an HEM with an inertia track was established, and an analytical solution was obtained in which the fixed point of dynamic stiffness in-phase was discovered theoretically. According to the phenomena of fixed points and the constant value of dynamic stiffness in-phase at higher bands, a new parameter identification method (PIM) was presented, which is clear in theory and is time and cost savings, the identified results are reliable. The results show that the fluid flow through an orifice can be replaced by a fluid flow through an equivalent length of inertia track. After this, a PIM for the fluid-flow local loss factor was developed. The identified results and the numerical simulations show that the reason the disturbing plate can keep the dynamic stiffness lower at higher bands is that the disturbing plate can sharply increase the quadratic fluid damping due to larger local loss, and then the resonance of the fluid flow through the decoupler channel or orifice is greatly attenuated. This conclusion is a useful attempt to explain the working principle of the disturbing plate.

Fan, Ranglin; Lu, Zhenhua

2007-09-01

224

Control of transient chaos in tent maps near crisis.??I.??Fixed point targeting

Combinatorial techniques are applied to the symbolic dynamics representing tran- sient chaotic behaviour in tent maps in order to solve the problem of OGY control to the non-trivial xed point occurring in such maps. This approach allows 'pre-image overlap' to be treated exactly. Closed forms for both the probability of control being achieved and the average number of iterations to

D. K. Arrowsmith

2000-01-01

225

The distributions of interisland gaps and captures zones for islands nucleated on a one-dimensional substrate during submonolayer deposition are considered using a novel retrospective view. This provides an alternative perspective on why scaling occurs in this continuously evolving system. Distributional fixed-point equations for the gaps are derived both with and without a mean-field approximation for nearest neighbor gap-size correlation. Solutions to the equations show that correct consideration of fragmentation bias justifies the mean-field approach, which can be extended to provide closed-from equations for the capture zones. Our results compare favorably to Monte Carlo data for both point and extended islands using a range of critical island size i=0,1,2,3. We also find satisfactory agreement with theoretical models based on more traditional fragmentation theory approaches. PMID:23214792

Mulheran, P A; O'Neill, K P; Grinfeld, M; Lamb, W

2012-11-01

226

Fixed-point theorems for a controlled withdrawal of the convexity of the values of a set-valued map

The question of the extent of the possible weakening of the convexity condition for the values of set-valued maps in the classical fixed-point theorems of Kakutani, Bohnenblust-Karlin, and Gliksberg is discussed. For an answer, one associates with each closed subset P of a Banach space a numerical function {alpha}{sub P}:(0,{infinity}){yields}[0,{infinity}), which is called the function of non-convexity of P. The closer {alpha}{sub P} is to zero, the 'more convex' is P. The equality {alpha}{sub P}{identical_to}0 is equivalent to the convexity of P. Results on selections, approximations, and fixed points for set-valued maps F of finite- and infinite-dimensional paracompact sets are established in which the equality {alpha}{sub F(x)}{identical_to}0 is replaced by conditions of the kind: {sup {alpha}}{sub F(x)} is less than 1{sup .} Several formalizations of the last condition are compared and the topological stability of constraints of this type is shown.

Semenov, P V [Moscow Pedagogical University, Moscow (Russian Federation)

1998-04-30

227

NASA Astrophysics Data System (ADS)

This paper outlines measurements made at the National Research Council Canada (NRC) of the thermodynamic melting temperatures of Co-C, Pt-C and Re-C fixed points that have been part of the high-temperature fixed-point research plan of Working Group 5 of the Consultative Committee for Thermometry (CCT-WG5) to assign melting temperatures to those fixed points. This document will outline the equipment used, describe the scheme used to calibrate a pyrometer with traceability to a cryogenic electrical substitution radiometer, and detail the method of measuring the fixed points. It will then report the uncertainties in the measurements and the results. A brief description of the improvements that we plan to implement to the scheme to reduce the uncertainties for future measurements will be given. The thermodynamic temperatures determined for the three fixed points are: 1597.776 K with an expanded uncertainty of 0.36 K, 2011.390 K with an expanded uncertainty of 0.55 K, and 2748.056 K with an expanded uncertainty of 0.95 K, for the Co-C, Pt-C and Re-C fixed points, respectively (all expanded uncertainties assume a 95% confidence interval and a Gaussian distribution).

Todd, A. D. W.; Woods, D. J.

2013-02-01

228

Corrective Action Unit (CAU) 516, Septic Systems and Discharge Points, is listed in the ''Federal Facility Agreement and Consent Order'' (FFACO) of 1996 (FFACO, 1996). CAU 516 consists of six Corrective Action Sites (CASs) located in Areas 3, 6, and 22 of the Nevada Test Site (NTS), which is located approximately 65 miles northwest of Las Vegas, Nevada (Figure 1). CAU 516 is comprised of the following six CASs: (1) 03-59-01 Building 3C-36 Septic System; (2) 03-59-02 Building 3C-45 Septic System; (3) 06-51-01 Sump and Piping; (4) 06-51-02 Clay Pipe and Debris; (5) 06-51-03 Clean-Out Box and Piping; and (6) 22-19-04 Vehicle Decontamination Area. Details on site history and site characterization results for CAU 516 are provided in the approved Corrective Action Investigation Plan (CAIP), (U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSA/NSO], 2003), and the approved Corrective Action Decision Document (CADD) (NNSA/NSO, 2004).

BECHTEL NEVADA; U.S. DEPARTMENT OF ENERGY, NATIONAL NUCLEAR SECURITY ADMINISTRATION NEVADA SITE OFFICE

2005-08-01

229

NASA Astrophysics Data System (ADS)

We use scaling and renormalization-group techniques to analyze the leading nonanalyticities in a Fermi liquid. We show that a physically motivated scaling hypothesis reproduces the results known from perturbation theory for the density of states, the density-of-states fluctuations, the specific heat, the spin susceptibility, and the nematic magnetic susceptibility. We also discuss the absence of nonanalytic terms in the density susceptibility. We then use a recent effective field theory for clean electron systems to derive the scaling hypothesis by means of renormalization-group techniques. This shows that the exponents (although not the prefactors) of the nonanalyticities that were previously derived by means of perturbative techniques are indeed exact, and can be understood as the leading corrections to scaling at the stable Fermi-liquid fixed point.

Belitz, D.; Kirkpatrick, T. R.

2014-01-01

230

NASA Astrophysics Data System (ADS)

We consider the problem of a heavy particle in a double well potential (DWP) interacting with an electron bath. Under general assumptions, we map the problem to a three-color logarithmic gas model, where the size of the core of the charged particles is proportional to the tunneling time, ?tun, of the heavy particle between the two wells. For times larger than ?tun this model is equivalent to the anisotropic two-channel Kondo (2CK) model in a transverse field. This allows us to establish a relationship between the microscopic parameters of DWP and the 2CK problem. We show that the strong coupling fixed point of the 2CK model can never be reached for the DWP problem, in agreement with the results of Kagan and Prokof'ev [Sov. Phys. JETP 69, 836 (1989)] and Aleiner et al. [Phys. Rev. Lett. 86, 2629 (2001)].

Aleiner, I. L.; Controzzi, D.

2002-07-01

231

In the real world, tools used for manipulation are pivoted with specialized tips for specific functions including grasping and cutting. Manipulating deformable virtual objects with them involves maintaining extended contact, which is difficult due to the variations in applied force. Our method consists in selecting a fixed set of points on the jaws of a pivoted tool, and placing them either equidistant or according to the geometry of the tool. Vertex and triangle proximities are calculated for each of the interacting deformable objects for collision detection. This method was successfully tested in a surgical simulation scenario where a deformable omental fat model was grasped and retracted while maintaining full contact with the pivoted tool tip at all times. PMID:21335856

Sankaranarayanan, Ganesh; Lu, Zhonghua; De, Suvranu

2011-01-01

232

The U.S Geological Survey, in cooperation with the Wisconsin Department of Natural Resources (WDNR) and in collaboration with the Root River Municipal Stormwater Permit Group monitored eight urban source areas representing six types of source areas in or near Madison, Wis. in an effort to improve characterization of particle-size distributions in urban stormwater by use of fixed-point sample collection methods. The types of source areas were parking lot, feeder street, collector street, arterial street, rooftop, and mixed use. This information can then be used by environmental managers and engineers when selecting the most appropriate control devices for the removal of solids from urban stormwater. Mixed-use and parking-lot study areas had the lowest median particle sizes (42 and 54 (u or mu)m, respectively), followed by the collector street study area (70 (u or mu)m). Both arterial street and institutional roof study areas had similar median particle sizes of approximately 95 (u or mu)m. Finally, the feeder street study area showed the largest median particle size of nearly 200 (u or mu)m. Median particle sizes measured as part of this study were somewhat comparable to those reported in previous studies from similar source areas. The majority of particle mass in four out of six source areas was silt and clay particles that are less than 32 (u or mu)m in size. Distributions of particles ranging from 500 (u or mu)m were highly variable both within and between source areas. Results of this study suggest substantial variability in data can inhibit the development of a single particle-size distribution that is representative of stormwater runoff generated from a single source area or land use. Continued development of improved sample collection methods, such as the depth-integrated sample arm, may reduce variability in particle-size distributions by mitigating the effect of sediment bias inherent with a fixed-point sampler.

Selbig, William R.; Bannerman, Roger T.

2011-01-01

233

NASA Astrophysics Data System (ADS)

Perturbative QCD (pQCD) running coupling a(Q2) (??s(Q2)/?) is expected to get modified at low spacelike momenta 0

Cveti?, Gorazd

2014-02-01

234

This Corrective Action Decision Document has been prepared for the Area 3 Building 03-60 Underground Discharge Point (Corrective Action Unit 423) in accordance with the Federal Facility Agreement and Consent Order of 1996 (FFACO, 1996). Corrective Action Unit 423 is located at the Tonopah Test Range and is comprised of Corrective Action Site 03-02-002-0308. The purpose of this Corrective Action Decision Document is to identify and provide a rationale for the selection of a recommended corrective action alternative for Corrective Action Unit 423. The scope of this Correction Action Decision Document consists of the following: ? Develop corrective action objectives. ? Identify corrective action alternative screening criteria. ? Develop corrective action alternatives. ? Perform detailed and comparative evaluations of the corrective action alternatives in relation to the corrective action objectives and screening criteria. ? Recommend and justify a preferred corrective action alternative for the Corrective Action Unit. In January 1998, a corrective action investigation was performed as set forth in the Corrective Action Investigation Plan for Corrective Action Unit No. 423: Building 03-60 Underground Discharge Point, Tonopah Test Range, Nevada (DOE/NV, 1997). A hydrocarbon plume was found to emanate from near the bottom of the Underground Discharge Point to the west. The plume encompasses approximately 65 square meters (700 square feet). The highest total petroleum hydrocarbon level detected was 2,400 milligrams per kilogram. No other contaminants were detected above preliminary action levels. Details of the investigation can be found in Appendix A of this document. Based on the potential exposure pathways identified during the Data Quality Objectives process, the following corrective action objectives have been identified for Corrective Action Unit 423: ? Prevent or mitigate human exposure to subsurface soil containing contaminants of concern. ? Prevent adverse impacts to groundwater quality. Based on the review of existing data, future land use assumption, and current operations at the Tonopah Test Range, the following alternatives were developed for consideration at the Building 03-60 Underground Discharge Point: ? Alternative 1 - No Action ? Alternative 2 - Closure in Place with Administrative Controls ? Alternative 3 - Partial Excavation, Disposal, and Administrative Controls ? Alternative 4 - In Situ Bioremediation The corrective action alternatives were evaluated based on four general corrective action standards and five remedy selection decision factors. Based on the results of this evaluation, the preferred alternative for Corrective Action Unit 423 is Alternative 2, Closure in Place with Administrative Controls. The preferred corrective action alternative was evaluated on technical merit, focusing on performance, reliability, feasibility, and safety. The alternative was judged to meet all requirements for the technical components evaluated. The alternative also meets all applicable state and federal regulations for closure of the site and will reduce potential future exposure pathways to the contaminated soils.

NONE

1998-06-01

235

Four-point vertices from the 2PI and 4PI effective actions

NASA Astrophysics Data System (ADS)

We consider a symmetric scalar theory with quartic coupling in two and three dimensions and compare the self-consistent four-point vertex obtained from the four-particle-irreducible effective action with the Bethe-Salpeter 4-vertex from the two-particle-irreducible effective action. At zero external momenta the two vertices agree well with each other when the coupling strength is small, but differences between them become more and more pronounced as the coupling strength is increased. We also study the momentum dependence of the two vertices and show that for certain momentum configurations they are almost identical but differ for general momentum arguments.

Carrington, M. E.; Fu, Wei-Jie; Mikula, P.; Pickering, D.

2014-01-01

236

Corrective Action Unit (CAU) 556, Dry Wells and Surface Release Points, is located in Areas 6 and 25 of the Nevada Test Site, 65 miles northwest of Las Vegas, Nevada. Corrective Action Unit 556 is comprised of four corrective action sites (CASs) listed below: •06-20-04, National Cementers Dry Well •06-99-09, Birdwell Test Hole •25-60-03, E-MAD Stormwater Discharge and Piping •25-64-01, Vehicle Washdown and Drainage Pit These sites are being investigated because existing information on the nature and extent of potential contamination is insufficient to evaluate and recommend corrective action alternatives. Additional information will be obtained by conducting a corrective action investigation before evaluating corrective action alternatives and selecting the appropriate corrective action for each CAS. The results of the field investigation will support a defensible evaluation of viable corrective action alternatives that will be presented in the Corrective Action Decision Document.

Grant Evenson

2007-02-01

237

Asymptotically free four-Fermi theory in 4 dimensions at the z=3 Lifshitz-like fixed point

NASA Astrophysics Data System (ADS)

We show that a Nambu-Jona-Lasinio type four-fermion coupling at the z=3 Lifshitz-like fixed point in 3+1 dimensions is asymptotically free and generates a mass scale dynamically. This result is nonperturbative in the limit of a large number of fermion species. The theory is ultraviolet complete and at low energies exhibits Lorentz invariance as an emergent spacetime symmetry. Many of our results generalize to z=d in odd d spatial dimensions; z=d=1 corresponds to the Gross-Neveu model. The above mechanism of mass generation has potential applications to the fermion mass problem and to dynamical electroweak symmetry breaking. We present a scenario in which a composite Higgs field arises from a condensate of these fermions, which then couples to quarks and leptons of the standard model. Such a scenario could eliminate the need for the Higgs potential and the associated hierarchy problem. We also show that the axial anomaly formula at z=3 coincides with the usual one in the relativistic domain.

Dhar, Avinash; Mandal, Gautam; Wadia, Spenta R.

2009-11-01

238

NASA Astrophysics Data System (ADS)

A new method of filling of high-temperature fixed-point cells based on metal-carbon eutectics and peritectics is suggested and tested. In this method a metal and carbon powder mixture is introduced not directly into the crucible, but into an additional container located just above the crucible. The mixture melts inside the container, and the already molten eutectic drops through a small hole in the bottom of the container and fills the crucible drop by drop. The method can be used to obtain a uniform ingot without porous or foundry cavities, to minimize the risk of contamination, and to avoid some other disadvantages. The method was applied to fabricate Re-C and WC-C cells using 5N purity materials. The cells demonstrated a good plateau shape with melting ranges of 0.2 K and 80 mK for Re-C and WC-C, respectively. The Re-C cell was compared with a cell built at NMIJ and showed good agreement with a difference of melting temperatures of only 45 mK.

Khlevnoy, B. B.; Grigoryeva, I. A.; Ibragimov, N. A.

2011-08-01

239

NASA Astrophysics Data System (ADS)

Critical phenomena of amorphous magnets with N order parameters are studied via the renormalized field theory and the replica method. Investigated model has amorphous properties only for N >= 2 and consists of two terms: the random exchange interactions and a term realizing random easy axes. Three coupling constants and two critical indices ? and ? are calculated up to O(?2)[? =4 -d(d: space dimensionality)]. A fixed point of O(sqrt?) for N = 1 (Ising) agrees with the stable Khmel'nitzkii fixed point. In the case N = 2(XY) or N = 3(Heisenberg), there is no stable fixed point, so that no second-order phase transition occurs. For N > Nc = 3.9123 + (0.57 ± 0.03) ?, one more stable (although unphysical) fixed point emerges. In the limit N ? ?, random easy axes give no change unless the intensity of random easy axes increases by the same power of N as N ? ?. It is also pointed out that obtained ? functions are applicable to the two-loop calculations for the problem of the non-Abelian gauge field with scalar coupling (Higgs model).

Oku, M.

1983-12-01

240

NASA Astrophysics Data System (ADS)

The silver and copper fixed-point blackbody sources of NPL were directly compared with those of LNE-Cnam using an IKE LP3 and an IKE LP5 at three wavelengths (650 nm, 795 nm and 903 nm). The two silver fixed points and the two copper fixed points were in excellent agreement with each other, with a difference of 11 mK for the silver and within 16 mK for the copper, with an expanded measurement uncertainty of between 10 mK and 20 mK depending on the pyrometer used. The temperature interval between the silver and copper freezing points was also measured using combinations of all four fixed points. The results with the NPL LP3 gave a value for the silver-copper temperature interval of 122.89 °C with an expanded uncertainty of 30 mK those with the LNE-Cnam LP5 gave a temperature interval of 122.87 °C also with an expanded uncertainty of 30 mK this compares with the ITS-90 value of 122.84 °C.

McEvoy, H. C.; Sadli, M.; Bourson, F.; Briaudeau, S.; Rougié, B.

2013-12-01

241

NASA Astrophysics Data System (ADS)

Ongoing work to improve the uniformity of vertically mounted furnaces, manufactured by Carbolite (e.g., Type TZF12/75—three-zone furnace capable of 1200 °C, with 75 mm inner bore) along the axis and across the working tube and/or equalizing block is reported. This involves adjusting the size of the end zones, the position of the control thermometers, and the use of cascade-control methods. Means regularly used at NPL to reduce electrical noise in some commercially available ac furnaces through a reduction in the voltage used to “fire” the heaters, and better use of thyristor controllers (by extending their cycle time) are described. The need to shield the controllers from local magnetic fields is described. With these measures, the electrical noise from ac furnaces can approach that of dc furnaces, without the large cost of a dc power supply. The application of new data analysis techniques (Allan deviation) will be shown to improve the representation of uninterrupted fixed-point traces (as used in ingot verification rather than PRT calibration). Reduction of statistical noise on the temperature measurements has been achieved for data on the freezing plateau by determining the statistically optimum averaging time. This shows that the statistical uncertainty in the determination of the temperature of a particular freezing plateau is less than 25 ?K and that noise (drift) from other sources, possibly due to variations in room temperature, starts to become appreciable over periods longer than a few tens of minutes. The measurement of freezing and melting plateaux at this level is aided by the introduction of new ASL-F900 bridge(s), and quieter/larger standard resistor baths.

Head, D. I.; Gray, J.; de Podesta, M.

2009-02-01

242

National Technical Information Service (NTIS)

This paper analyzes the problem of global asymptotic stability of delta-operator formulated discrete-time systems implemented in fixed-point arithmetic. It is shown that the free response of such a system tends to produce period one limit cycles if conven...

K. Premaratne P. H. Bauer

1994-01-01

243

We study the generalized Ulam-Hyers stability, the well-posedness, and the limit shadowing of the fixed point problem for new type of generalized contraction mapping, the so-called ?-?-contraction mapping. Our results in this paper are generalized and unify several results in the literature as the result of Geraghty (1973) and the Banach contraction principle. PMID:24592174

Sintunavarat, Wutiphol

2014-01-01

244

We introduce an iterative process for finding an element of a common fixed point of a finite family of Bregman weak relatively nonexpansive mappings. Our theorems improve and unify most of the results that have been proved for this important class of nonlinear operators. PMID:24757423

Zegeye, Habtu; Shahzad, Naseer

2014-01-01

245

NASA Astrophysics Data System (ADS)

On reflexive real Banach spaces, a fixed point theorem in weak topology for successively recurrent system of fuzzy-set-valued nonlinear mapping equations and its application to ring nonlinear network systems are theoretically discussed in detail. An arbitrarily-level likelihood signal estimation is established, here.

Horiuchi, Kazuo

246

We study the generalized Ulam-Hyers stability, the well-posedness, and the limit shadowing of the fixed point problem for new type of generalized contraction mapping, the so-called ?-?-contraction mapping. Our results in this paper are generalized and unify several results in the literature as the result of Geraghty (1973) and the Banach contraction principle.

2014-01-01

247

We introduce an iterative process for finding an element of a common fixed point of a finite family of Bregman weak relatively nonexpansive mappings. Our theorems improve and unify most of the results that have been proved for this important class of nonlinear operators.

2014-01-01

248

We consider the effective spin Hamiltonian describing a mixture of two species of pseudo-spin-(1/2) Bose gases with interspecies spin exchange. First we analyze the stability of the fixed points of the corresponding classical dynamics, of which the signature is found in quantum dynamics with a disentangled initial state. Focusing on the case without an external potential, we find all the ground states by taking into account quantum fluctuations around the classical ground state in each parameter regime. The nature of entanglement and its relation with classical bifurcation is investigated. When the total spins of the two species are unequal, the maximal entanglement at the parameter point of classical bifurcation is possessed by the excited state corresponding to the classical fixed point which bifurcates, rather than by the ground state.

Wu Rukuan [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China); Department of Physics, Zhejiang Normal University, Jinhua 321004 (China); Shi Yu [State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433 (China)

2011-12-15

249

Techniques are recommended for comparisons, at the highest levels of accuracy, of fixed-point cells of the defining fixed points, excluding the vapour-pressure points, of the ITS-90, which are used for contact thermometry. The authors are the members of Working Group 1 of the Consultative Committee for Thermometry (CCT) of the Comité International des Poids et Mesures, dealing with Defining Fixed

B. W. Mangum; P. Bloembergen; M. V. Chattle; B. Fellmuth; P. Marcarino; A. I. Pokhodun

1999-01-01

250

The demands of modern radiation thermometry and radiometry are being satisfied by a large variety of high-precision unique BB sources (both fixed-point and variable temperature) designed for a wide range of temperature from 100 K to 3500 K. The paper contains a detailed review of low-, medium- and high-temperature precision blackbodies developed at VNIIOFI as the basis of the spectral

V. I. Sapritsky; B. B. Khlevnoy; S. A. Ogarev; V. E. Privalsky; M. L. Samoylov; M. K. Sakharov; A. A. Bourdakin; A. S. Panfilov

2006-01-01

251

ERIC Educational Resources Information Center

Against the background of Swedish preschool's historical and traditional functions in Swedish society, this article focuses on some of the choice points and their implications for professional and organisational development in preschool. By combining feminist pragmatism and feminist action research, some analytical points are made regarding the…

Gillberg, Claudia

2011-01-01

252

NASA Technical Reports Server (NTRS)

Detail calculations are presented of the shifts in stick-fixed neutral point of the Republic XF-12 airplane due to the windmilling propellers and to the fuselage. The results of these calculations differ somewhat from those previously made for this airplane by Republic Aviation Corporation personnel under the direction of Langley flight division personnel. Due to these differences the neutral point for the airplane is predicted to be 37.8 percent mean aerodynamic chord, instead of 40.8 percent mean aerodynamic chord as previously reported.

White, M. D.

1944-01-01

253

This Corrective Action Investigation Plan (CAIP) contains the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Sites Office's (NNSA/NSO's) approach to collect the data necessary to evaluate corrective action alternatives appropriate for the closure of Corrective Action Unit (CAU) 516, Septic Systems and Discharge Points, Nevada Test Site (NTS), Nevada, under the Federal Facility Agreement and Consent Order. CAU 516 consists of six Corrective Action Sites: 03-59-01, Building 3C-36 Septic System; 03-59-02, Building 3C-45 Septic System; 06-51-01, Sump Piping, 06-51-02, Clay Pipe and Debris; 06-51-03, Clean Out Box and Piping; and 22-19-04, Vehicle Decontamination Area. Located in Areas 3, 6, and 22 of the NTS, CAU 516 is being investigated because disposed waste may be present without appropriate controls, and hazardous and/or radioactive constituents may be present or migrating at concentrations and locations that could potentially pose a threat to human health and the environment. Existing information and process knowledge on the expected nature and extent of contamination of CAU 516 are insufficient to select preferred corrective action alternatives; therefore, additional information will be obtained by conducting a corrective action investigation. The results of this field investigation will support a defensible evaluation of corrective action alternatives in the corrective action decision document. Record of Technical Change No. 1 is dated 3/2004.

U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Sites Office

2003-04-28

254

NASA Astrophysics Data System (ADS)

The kinetic energy of barotropic flow coupled to an infinitely massive rotating sphere by an unresolved complex torque mechanism is approximated by a discrete spin lattice model of fluid vorticity on a rotating sphere, analogous to a one-step renormalized Ising model on a sphere with global interactions. The constrained energy functional is a function of spin spin coupling and spin coupling with the rotation of the sphere. A mean field approximation similar to the Curie Weiss theory, modeled after that used by Bragg and Williams to treat a 2D Ising model of ferromagnetism, is used to find the barotropic vorticity states at thermal equilibrium for a given temperature and rotational frequency of the sphere. A fixed point equation for the most probable barotropic flow state is one of the main results. This provides a crude model of super- and sub-rotating planetary atmospheres in which the barotropic flow can be considered to be the vertically averaged rotating stratified atmosphere and where a key order parameter is the changeable amount of angular momentum in the barotropic fluid. Using the crudest two domains partition of the resulting fixed point equation, we find that in positive temperatures associated with low-energy flows, for fixed planetary spin larger than ?>0 there is a continuous transition from a disordered state in higher temperatures to a counter-rotating solid-body flow state in lower positive temperatures. The most probable state is a weakly counter-rotating mixed state for all positive temperatures when planetary spin is smaller than ?. For sufficiently large spins ?>2?, there is a single smooth change from slightly pro-rotating mixed states to a strongly pro-rotating ordered state as the negative value of T increases (or decreases in absolute value). But for smaller spins ?<2? there is a transition from a predominantly mixed state (for T?-1) to a pro-rotating state at ?(?)<0 plus a second ?c?, for which the fixed point equation has three fixed points when ?fixed points because it has the highest free energy—at negative temperatures the thermodynamically stable state is the one with the maximum free energy. In the non-rotating case (?=0) the most probable state changes from a mixed state for all positive and large absolute-valued negative temperatures to an ordered state of solid-body flow at small absolute-valued negative temperatures through a standard symmetry-breaking second-order phase transition. The predictions of this model for the non-rotating problem and the rotating problem agree with the predictions of the simple mean field model and the spherical model. This model differs from previous mean field theories for quasi-2D turbulence in not fixing angular momentum nor relative enstrophy—a property which increases its applicability to coupled fluid sphere systems and by extension to 2D turbulent flows in complex domains such as no-slip square boundaries where only the total circulation is fixed—as opposed to classical statistical equilibrium models such as the vortex gas model and Miller Robert theories that fix all the vorticity moments. Furthermore, this Bragg mean field theory is well-defined for all positive and negative temperatures unlike the classical energy enstrophy theories.

Lim, Chjan C.; Singh Mavi, Rajinder

2007-07-01

255

We examined elbow muscle activities and movement kinematics to determine how subjects combine elementary control actions in performing movements with one and two trajectory segments. In reaching, subjects made a rapid elbow flexion to a visual target before stabilizing the limb with either a low or a higher level of elbow flexor/extensor coactivity (CoA), which was cued by target diameter. Cursor diameter provided real-time biofeedback of actual muscle CoA. In reversing, the limb was to reverse direction within the target and return to the origin with minimal CoA. We previously reported that subjects overshoot the goal when attempting a reversal after first having learned to reach accurately to the same target. Here we test the hypothesis that this hypermetria results because reversals co-opt the initial feedforward control action from the preceding trained reach, thereby failing to account for task-dependent changes in limb impedance induced by differences in flexor/extensor coactivity as the target is acquired (higher in reaching than reversing). Instructed increases in elbow CoA began mid-reach, thus increasing elbow impedance and reducing transient oscillations present in low CoA movments. Flexor EMG alone increased at movement onset. Test reversals incorporated the initial agonist activity of previous reaches but not the increased coactivity at the target, thus leading to overshoot. Moreover, we observed elevated coactivity in reversals upon returning to the origin even though coactivity in reaching was centered at the goal target. These findings refute the idea that the brain necessarily invokes distinct unitary control actions for reaches and reversals made to the same target. Instead, reaches and reversals share a common control action that initiates trajectories toward their target and another later control action that terminates movement and stabilizes the limb about its final resting posture, which differs in the two tasks.

Ghez, Claude; Asnani, Supriya

2011-01-01

256

This Corrective Action Decision Document (CADD) has been prepared for Corrective Action Unit (CAU) 516, Septic Systems and Discharge Points, Nevada Test Site, Nevada, in accordance with the ''Federal Facility Agreement and Consent Order'' (1996). Corrective Action Unit 516 is comprised of the following Corrective Action Sites (CASs): (1) 03-59-01 - Bldg 3C-36 Septic System; (2) 03-59-02 - Bldg 3C-45 Septic System; (3) 06-51-01 - Sump and Piping; (4) 06-51-02 - Clay Pipe and Debris; (5) 06-51-03 - Clean Out Box and Piping; and (7) 22-19-04 - Vehicle Decontamination Area. The purpose of this CADD is to identify and provide the rationale for the recommendation of an acceptable corrective action alternative for each CAS within CAU 516. Corrective action investigation activities were performed between July 22 and August 14, 2003, as set forth in the Corrective Action Investigation Plan. Supplemental sampling was conducted in late 2003 and early 2004.

Alfred N. Wickline

2004-04-01

257

Many recent experiments make use of a quantum point contact (QPC) as a qubit readout (e.g., of a double quantum dot (DQD) qubit). It has long been realized that QPC current fluctuations can give rise to inelastic back-action effects on the DQD [1] [2]. In contrast, the role of QPC charge fluctuations in generating inelastic back-action has not been fully

Carolyn Young; Aashish Clerk

2009-01-01

258

NASA Astrophysics Data System (ADS)