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Sample records for two-level systems subject

  1. Darboux transformation for two-level system

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.; Baldiotti, M.; Gitman, D.; Shamshutdinova, V. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil)

    2005-06-01

    We develop the Darboux procedure for the case of the two-level system. In particular, it is demonstrated that one can construct the Darboux intertwining operator that does not violate the specific structure of the equations of the two-level system, transforming only one real potential into another real potential. We apply the obtained Darboux transformation to known exact solutions of the two-level system. Thus, we find three classes of new solutions for the two-level system and the corresponding new potentials that allow such solutions. (Abstract Copyright [2005], Wiley Periodicals, Inc.)

  2. Experimental Hamiltonian identification for controlled two-level systems

    International Nuclear Information System (INIS)

    Schirmer, S.G.; Kolli, A.; Oi, D.K.L.

    2004-01-01

    We present a strategy to empirically determine the internal and control Hamiltonians for an unknown two-level system (black box) subject to various (piecewise constant) control fields when direct readout by measurement is limited to a single, fixed observable

  3. Two-level systems driven by large-amplitude fields

    Science.gov (United States)

    Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.

    2009-03-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.

  4. Two-level systems driven by large-amplitude fields

    International Nuclear Information System (INIS)

    Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.; Nori, Franco

    2007-01-01

    We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems

  5. Stationary states of two-level open quantum systems

    International Nuclear Information System (INIS)

    Gardas, Bartlomiej; Puchala, Zbigniew

    2011-01-01

    A problem of finding stationary states of open quantum systems is addressed. We focus our attention on a generic type of open system: a qubit coupled to its environment. We apply the theory of block operator matrices and find stationary states of two-level open quantum systems under certain conditions applied on both the qubit and the surrounding.

  6. The geometric phase in two-level atomic systems

    International Nuclear Information System (INIS)

    Tian Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Randall Babbitt, Wm.

    2004-01-01

    We report the observation of the geometric phase in a closed two-level atomic system using stimulated photon echoes. The two-level system studied consists of the two-electronic energy levels ( 3 H 4 and 3 H 6 ) of Tm 3+ doped in YAG crystal. When a two-level atom at an arbitrary superposition state is excited by a pair of specially designed laser pulses, the excited state component gains a relative phase with respect to the ground state component. We identified the phase shift to be of pure geometric nature. The dynamic phase associated to the driving Hamiltonian is unchanged. The experiment results of the phase change agree with the theory to the extent of the measurement limit

  7. Mixing phases of unstable two-level systems

    International Nuclear Information System (INIS)

    Sokolov, V.V.; Brentano, P. von.

    1993-01-01

    An unstable two-level system decaying into an arbitrary number of channels is considered. It is shown that the mixing phases of the two overlapping resonances can be expressed in the terms of their partial widths and one additional universal mixing parameter. Some applications to a doublet of 2 + resonances in 8 Be and to the ρ-ω systems are considered. 18 refs

  8. Perturbation Theory for Open Two-Level Nonlinear Quantum Systems

    International Nuclear Information System (INIS)

    Zhang Zhijie; Jiang Dongguang; Wang Wei

    2011-01-01

    Perturbation theory is an important tool in quantum mechanics. In this paper, we extend the traditional perturbation theory to open nonlinear two-level systems, treating decoherence parameter γ as a perturbation. By this virtue, we give a perturbative solution to the master equation, which describes a nonlinear open quantum system. The results show that for small decoherence rate γ, the ratio of the nonlinear rate C to the tunneling coefficient V (i.e., r = C/V) determines the validity of the perturbation theory. For small ratio r, the perturbation theory is valid, otherwise it yields wrong results. (general)

  9. Atomistic study of two-level systems in amorphous silica

    Science.gov (United States)

    Damart, T.; Rodney, D.

    2018-01-01

    Internal friction is analyzed in an atomic-scale model of amorphous silica. The potential energy landscape of more than 100 glasses is explored to identify a sample of about 700 two-level systems (TLSs). We discuss the properties of TLSs, particularly their energy asymmetry and barrier as well as their deformation potential, computed as longitudinal and transverse averages of the full deformation potential tensors. The discrete sampling is used to predict dissipation in the classical regime. Comparison with experimental data shows a better agreement with poorly relaxed thin films than well relaxed vitreous silica, as expected from the large quench rates used to produce numerical glasses. The TLSs are categorized in three types that are shown to affect dissipation in different temperature ranges. The sampling is also used to discuss critically the usual approximations employed in the literature to represent the statistical properties of TLSs.

  10. Two-level tunneling systems in amorphous alumina

    Science.gov (United States)

    Lebedeva, Irina V.; Paz, Alejandro P.; Tokatly, Ilya V.; Rubio, Angel

    2014-03-01

    The decades of research on thermal properties of amorphous solids at temperatures below 1 K suggest that their anomalous behaviour can be related to quantum mechanical tunneling of atoms between two nearly equivalent states that can be described as a two-level system (TLS). This theory is also supported by recent studies on microwave spectroscopy of superconducting qubits. However, the microscopic nature of the TLS remains unknown. To identify structural motifs for TLSs in amorphous alumina we have performed extensive classical molecular dynamics simulations. Several bistable motifs with only one or two atoms jumping by considerable distance ~ 0.5 Å were found at T=25 K. Accounting for the surrounding environment relaxation was shown to be important up to distances ~ 7 Å. The energy asymmetry and barrier for the detected motifs lied in the ranges 0.5 - 2 meV and 4 - 15 meV, respectively, while their density was about 1 motif per 10 000 atoms. Tuning of motif asymmetry by strain was demonstrated with the coupling coefficient below 1 eV. The tunnel splitting for the symmetrized motifs was estimated on the order of 0.1 meV. The discovered motifs are in good agreement with the available experimental data. The financial support from the Marie Curie Fellowship PIIF-GA-2012-326435 (RespSpatDisp) is gratefully acknowledged.

  11. SUBJECT «NUMBER SYSTEMS» IN TWO-LEVELED FORMAT PREPARATION TEACHERS OF MATHEMATICS

    Directory of Open Access Journals (Sweden)

    V. I. Igoshin

    2017-01-01

    Full Text Available The aim of this article is to analyze the format of a two-leveled training – bachelor and master – future teachers of mathematics from the point of view of the content of mathematical material, which is to develop prospective teachers of mathematics at those two levels, shaping their professional competence.Methods. The study involves the theoretical methods: the analysis of pedagogical and methodical literature, normative documents; historical, comparative and logical analysis of the content of pedagogical mathematical education; forecasting, planning and designing of two-leveled methodical system of training of future teachers of mathematics.Results and scientific novelty. The level differentiation of the higher education system requires developing the appropriate curricula for undergraduate and graduate programs. The fundamental principle must be the principle of continuity – the magister must continue to deepen and broaden knowledge and skills, along with competences acquired, developed and formed on the undergraduate level. From these positions, this paper examines the course «Number Systems» – the most important in terms of methodology course for future mathematics teachers, and shows what content should be filled with this course at the undergraduate level and the graduate level. At the undergraduate level it is proposed to study classical number systems – natural, integer, rational, real and complex. Further extensions of the number systems are studied at the graduate level. The theory of numeric systems is presented as a theory of algebraic systems, arising at the intersection of algebra and mathematical logic. Here we study algebras over a field, division algebra over a field, an alternative algebra with division over the field, Jordan algebra, Lie algebra. Comprehension of bases of the theory of algebras by the master of the «mathematical education» profile will promote more conscious

  12. Franson Interference Generated by a Two-Level System

    Science.gov (United States)

    Peiris, M.; Konthasinghe, K.; Muller, A.

    2017-01-01

    We report a Franson interferometry experiment based on correlated photon pairs generated via frequency-filtered scattered light from a near-resonantly driven two-level semiconductor quantum dot. In contrast to spontaneous parametric down-conversion and four-wave mixing, this approach can produce single pairs of correlated photons. We have measured a Franson visibility as high as 66%, which goes beyond the classical limit of 50% and approaches the limit of violation of Bell's inequalities (70.7%).

  13. Minimum time control of a pair of two-level quantum systems with opposite drifts

    International Nuclear Information System (INIS)

    Romano, Raffaele; D’Alessandro, Domenico

    2016-01-01

    In this paper we solve two equivalent time optimal control problems. On one hand, we design the control field to implement in minimum time the SWAP (or equivalent) operator on a two-level system, assuming that it interacts with an additional, uncontrollable, two-level system. On the other hand, we synthesize the SWAP operator simultaneously, in minimum time, on a pair of two-level systems subject to opposite drifts. We assume that it is possible to perform three independent control actions, and that the total control strength is bounded. These controls either affect the dynamics of the target system, under the first perspective, or, simultaneously, the dynamics of both systems, in the second view. We obtain our results by using techniques of geometric control theory on Lie groups. In particular, we apply the Pontryagin maximum principle, and provide a complete characterization of singular and nonsingular extremals. Our analysis shows that the problem can be formulated as the motion of a material point in a central force, a well known system in classical mechanics. Although we focus on obtaining the SWAP operator, many of the ideas and techniques developed in this work apply to the time optimal implementation of an arbitrary unitary operator. (paper)

  14. Risk Analysis of a Two-Level Supply Chain Subject to Misplaced Inventory

    Directory of Open Access Journals (Sweden)

    Lijing Zhu

    2017-06-01

    Full Text Available Misplaced inventory is prevalent in retail stores and may lead to the overall poor performance of the supply chain. We explore the impact of misplaced inventory on a two-level supply chain, which consists of a risk-neutral supplier and a risk-averse retailer. The supplier decides the wholesale price to maximize her profit, whereas the retailer decides the order quantity to maximize his utility. Under the Conditional Value-at-Risk (CVaR criterion, we formulate the problem as a Stackelberg game model and obtain the equilibrium solutions in three cases: (i information asymmetry about inventory errors exists; (ii the retailer shares information about inventory errors with the supplier; and (iii in order to reduce misplaced inventory, the supply chain deploys Radio-Frequency Identification (RFID technology. The benefits of information sharing and RFID implementation are explored. A revenue and cost sharing contract is proposed to coordinate the supply chain and to allocate the cost savings from RFID implementation among supply chain participants. Finally, we provide managerial insights for risk-averse decision makers that are considering investing in the RFID technology.

  15. Comprehensive solutions to the Bloch equations and dynamical models for open two-level systems

    Science.gov (United States)

    Skinner, Thomas E.

    2018-01-01

    The Bloch equation and its variants constitute the fundamental dynamical model for arbitrary two-level systems. Many important processes, including those in more complicated systems, can be modeled and understood through the two-level approximation. It is therefore of widespread relevance, especially as it relates to understanding dissipative processes in current cutting-edge applications of quantum mechanics. Although the Bloch equation has been the subject of considerable analysis in the 70 years since its inception, there is still, perhaps surprisingly, significant work that can be done. This paper extends the scope of previous analyses. It provides a framework for more fully understanding the dynamics of dissipative two-level systems. A solution is derived that is compact, tractable, and completely general, in contrast to previous results. Any solution of the Bloch equation depends on three roots of a cubic polynomial that are crucial to the time dependence of the system. The roots are typically only sketched out qualitatively, with no indication of their dependence on the physical parameters of the problem. Degenerate roots, which modify the solutions, have been ignored altogether. Here the roots are obtained explicitly in terms of a single real-valued root that is expressed as a simple function of the system parameters. For the conventional Bloch equation, a simple graphical representation of this root is presented that makes evident the explicit time dependence of the system for each point in the parameter space. Several intuitive, visual models of system dynamics are developed. A Euclidean coordinate system is identified in which any generalized Bloch equation is separable, i.e., the sum of commuting rotation and relaxation operators. The time evolution in this frame is simply a rotation followed by relaxation at modified rates that play a role similar to the standard longitudinal and transverse rates. These rates are functions of the applied field, which

  16. Excitation transfer in two two-level systems coupled to an oscillator

    International Nuclear Information System (INIS)

    Hagelstein, P L; Chaudhary, I U

    2008-01-01

    We consider a generalization of the spin-boson model in which two different two-level systems are coupled to an oscillator, under conditions where the oscillator energy is much less than the two-level system energies, and where the oscillator is highly excited. We find that the two-level system transition energy is shifted, producing a Bloch-Siegert shift in each two-level system similar to what would be obtained if the other were absent. At resonances associated with energy exchange between a two-level system and the oscillator, the level splitting is about the same as would be obtained in the spin-boson model at a Bloch-Siegert resonance. However, there occur resonances associated with the transfer of excitation between one two-level system and the other, an effect not present in the spin-boson model. We use a unitary transformation leading to a rotated system in which terms responsible for the shift and splittings can be identified. The level splittings at the anticrossings associated with both energy exchange and excitation transfer resonances are accounted for with simple two-state models and degenerate perturbation theory using operators that appear in the rotated Hamiltonian

  17. Controlling the optical bistability and multistability in a two-level pumped-probe system

    International Nuclear Information System (INIS)

    Mahmoudi, Mohammad; Sahrai, Mostafa; Masoumeh Mousavi, Seyede

    2010-01-01

    We study the behavior of the optical bistability (OB) and multistability (OM) in a two-level pumped-probe atomic system by means of a unidirectional ring cavity. We show that the optical bistability in a two-level atomic system can be controlled by adjusting the intensity of the pump field and the detuning between two fields. We find that applying the pumping field decreases the threshold of the optical bistability.

  18. Resonant retuning of Rabi oscillations in a two-level system

    International Nuclear Information System (INIS)

    Leonov, A.V.; Feranchuk, I.D.

    2009-01-01

    The evolution of a two-level system in a single-mode quantum field is considered beyond the rotating wave approximation. The existence of quasi-degenerate energy levels is shown to influence the essential characteristics of temporal and amplitude Rabi oscillations of the system in a resonant manner. (authors)

  19. Excitation of graphene plasmons as an analogy with the two-level system

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiahui [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Lv, Bo, E-mail: lb19840313@126.com [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China); Li, Rujiang [College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027 (China); Ma, Ruyu; Chen, Wan; Meng, Fanyi [Microwave and Electromagnetic Laboratory, Harbin Institute of Technology, No. 92, Xidazhi Street, Nangang District, Harbin City, Heilongjiang Province (China)

    2016-02-15

    The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

  20. Excitation of graphene plasmons as an analogy with the two-level system

    International Nuclear Information System (INIS)

    Fu, Jiahui; Lv, Bo; Li, Rujiang; Ma, Ruyu; Chen, Wan; Meng, Fanyi

    2016-01-01

    The excitation of graphene plasmons (GPs) is presented as an interaction between the GPs and the incident electromagnetic field. In this Letter, the excitation of GPs in a plasmonic system is interpreted as an analogy with the two-level system by taking the two-coupled graphene-covered gratings as an example. Based on the equivalent circuit theory, the excitation of GPs in the graphene-covered grating is equivalent to the resonance of an oscillator. Thus, according to the governing equation, the electric currents at the resonant frequencies for two-coupled graphene-covered gratings correspond to the energy states in a two-level system. In addition, the excitation of GPs in different two-coupled graphene-covered gratings is numerically studied to validate our theoretical model. Our work provides an intuitive understanding of the excitation of GPs using an analogy with the two-level system. - Highlights: • The excitation of graphene plasmons (GPs) in graphene-covered grating is equivalent to the resonance of an oscillator. • We establish the equivalent circuit of two-level system to analyze the resonant character. • The excitation of GPs in different two-coupled graphene-covered gratings are numerically studied to validate our theoretical model.

  1. Exact Solution of the Two-Level System and the Einstein Solid in the Microcanonical Formalism

    Science.gov (United States)

    Bertoldi, Dalia S.; Bringa, Eduardo M.; Miranda, E. N.

    2011-01-01

    The two-level system and the Einstein model of a crystalline solid are taught in every course of statistical mechanics and they are solved in the microcanonical formalism because the number of accessible microstates can be easily evaluated. However, their solutions are usually presented using the Stirling approximation to deal with factorials. In…

  2. Crossing rule for a PT-symmetric two-level time-periodic system

    International Nuclear Information System (INIS)

    Moiseyev, Nimrod

    2011-01-01

    For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

  3. Non-zero temperature two-mode squeezing for time-dependent two-level systems

    International Nuclear Information System (INIS)

    Aliaga, J.; Gruver, J.L.; Proto, A.N.; Cerdeira, H.A.

    1994-01-01

    A Maximum Entropy Principle density matrix method, valid for systems with temperature different from zero, is presented making it possible two-mode squeezed states in two-level systems with relevant operators and Hamiltonian connected with O(3,2). A method which allows one to relate the appearance of squeezing to the relevant operators, included in order to define the density matrix of the system is given. (author). 14 refs, 1 fig

  4. The simulation of the non-Markovian behaviour of a two-level system

    Science.gov (United States)

    Semina, I.; Petruccione, F.

    2016-05-01

    Non-Markovian relaxation dynamics of a two-level system is studied with the help of the non-linear stochastic Schrödinger equation with coloured Ornstein-Uhlenbeck noise. This stochastic Schrödinger equation is investigated numerically with an adapted Platen scheme. It is shown, that the memory effects have a significant impact to the dynamics of the system.

  5. Minimax terminal approach problem in two-level hierarchical nonlinear discrete-time dynamical system

    Energy Technology Data Exchange (ETDEWEB)

    Shorikov, A. F., E-mail: afshorikov@mail.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002, Russia Institute of Mathematics and Mechanics, Ural Branch of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation)

    2015-11-30

    We consider a discrete–time dynamical system consisting of three controllable objects. The motions of all objects are given by the corresponding vector nonlinear or linear discrete–time recurrent vector relations, and control system for its has two levels: basic (first or I level) that is dominating and subordinate level (second or II level) and both have different criterions of functioning and united a priori by determined informational and control connections defined in advance. For the dynamical system in question, we propose a mathematical formalization in the form of solving a multistep problem of two-level hierarchical minimax program control over the terminal approach process with incomplete information and give a general scheme for its solving.

  6. Experiences of building a medical data acquisition system based on two-level modeling.

    Science.gov (United States)

    Li, Bei; Li, Jianbin; Lan, Xiaoyun; An, Ying; Gao, Wuqiang; Jiang, Yuqiao

    2018-04-01

    Compared to traditional software development strategies, the two-level modeling approach is more flexible and applicable to build an information system in the medical domain. However, the standards of two-level modeling such as openEHR appear complex to medical professionals. This study aims to investigate, implement, and improve the two-level modeling approach, and discusses the experience of building a unified data acquisition system for four affiliated university hospitals based on this approach. After the investigation, we simplified the approach of archetype modeling and developed a medical data acquisition system where medical experts can define the metadata for their own specialties by using a visual easy-to-use tool. The medical data acquisition system for multiple centers, clinical specialties, and diseases has been developed, and integrates the functions of metadata modeling, form design, and data acquisition. To date, 93,353 data items and 6,017 categories for 285 specific diseases have been created by medical experts, and over 25,000 patients' information has been collected. OpenEHR is an advanced two-level modeling method for medical data, but its idea to separate domain knowledge and technical concern is not easy to realize. Moreover, it is difficult to reach an agreement on archetype definition. Therefore, we adopted simpler metadata modeling, and employed What-You-See-Is-What-You-Get (WYSIWYG) tools to further improve the usability of the system. Compared with the archetype definition, our approach lowers the difficulty. Nevertheless, to build such a system, every participant should have some knowledge in both medicine and information technology domains, as these interdisciplinary talents are necessary. Copyright © 2018 Elsevier B.V. All rights reserved.

  7. Rapid characterization of microscopic two-level systems using Landau-Zener transitions in a superconducting qubit

    International Nuclear Information System (INIS)

    Tan, Xinsheng; Yu, Haifeng; Yu, Yang; Han, Siyuan

    2015-01-01

    We demonstrate a fast method to detect microscopic two-level systems in a superconducting phase qubit. By monitoring the population leak after sweeping the qubit bias flux, we are able to measure the two-level systems that are coupled with the qubit. Compared with the traditional method that detects two-level systems by energy spectroscopy, our method is faster and more sensitive. This method supplies a useful tool to investigate two-level systems in solid-state qubits

  8. Dynamics of quantum Fisher information in a two-level system coupled to multiple bosonic reservoirs

    Science.gov (United States)

    Wang, Guo-You; Guo, You-Neng; Zeng, Ke

    2015-11-01

    We consider the optimal parameter estimation for a two-level system coupled to multiple bosonic reservoirs. By using quantum Fisher information (QFI), we investigate the effect of the Markovian reservoirs’ number N on QFI in both weak and strong coupling regimes for a two-level system surrounded by N zero-temperature reservoirs of field modes initially in the vacua. The results show that the dynamics of QFI non-monotonically decays to zero with revival oscillations at some time in the weak coupling regime depending on the reservoirs’ parameters. Furthermore, we also present the relations between the QFI flow, the flows of energy and information, and the sign of the decay rate to gain insight into the physical processes characterizing the dynamics. Project supported by the Hunan Provincial Innovation Foundation for Postgraduate, China (Grant No. CX2014B194) and the Scientific Research Foundation of Hunan Provincial Education Department, China (Grant No. 13C039).

  9. Feedback controlled dephasing and population relaxation in a two-level system

    International Nuclear Information System (INIS)

    Wang Jin

    2009-01-01

    This Letter presents the maximum achievable stability and purity that can be obtained in a two-level system with both dephasing and population relaxation processes by using homodyne-mediated feedback control. An analytic formula giving the optimal amplitudes of the driving and feedback for the steady-state is also presented. Experimental examples are used to show the importance of controlling the dephasing process.

  10. Effective Hamiltonians, two level systems, and generalized Maxwell-Bloch equations

    International Nuclear Information System (INIS)

    Sczaniecki, L.

    1981-02-01

    A new method is proposed involving a canonical transformation leading to the non-secular part of time-independent perturbation calculus. The method is used to derive expressions for effective Shen-Walls Hamiltonians which, taken in the two-level approximation and on the inclusion of non-Hamiltonian terms into the dynamics of the system, lead to generalized Maxwell-Bloch equations. The rotating wave approximation is written anew within the framework of our formalism. (author)

  11. Understanding of phase modulation in two-level systems through inverse scattering

    International Nuclear Information System (INIS)

    Hasenfeld, A.; Hammes, S.L.; Warren, W.S.

    1988-01-01

    Analytical and numerical calculations describe the effects of shaped radiation pulses on two-level systems in terms of quantum-mechanical scattering. Previous results obtained in the reduced case of amplitude modulation are extended to the general case of simultaneous amplitude and phase modulation. We show that an infinite family of phase- and amplitude-modulated pulses all generate rectangular inversion profiles. Experimental measurements also verify the theoretical analysis

  12. Aspects of two-level systems under external time-dependent fields

    Energy Technology Data Exchange (ETDEWEB)

    Bagrov, V.G.; Wreszinski, W.F. [Tomsk State University and Tomsk Institute of High Current Electronics (Russian Federation); Barata, J.C.A.; Gitman D.M. [Universidade de Sao Paulo, Instituto de Fisica (Brazil)]. E-mails: jbarata@fma.if.usp.br; gitman@fma.if.usp.br

    2001-12-14

    The dynamics of two-level systems in time-dependent backgrounds is under consideration. We present some new exact solutions in special backgrounds decaying in time. On the other hand, following ideas of Feynman et al, we discuss in detail the possibility of reducing the quantum dynamics to a classical Hamiltonian system. This, in particular, opens the possibility of directly applying powerful methods of classical mechanics (e.g. KAM methods) to study the quantum system. Following such an approach, we draw conclusions of relevance for 'quantum chaos' when the external background is periodic or quasi-periodic in time. (author)

  13. Renormalization of correlations in a quasiperiodically forced two-level system: quadratic irrationals

    International Nuclear Information System (INIS)

    Mestel, B D; Osbaldestin, A H

    2004-01-01

    Generalizing from the case of golden mean frequency to a wider class of quadratic irrationals, we extend our renormalization analysis of the self-similarity of correlation functions in a quasiperiodically forced two-level system. We give a description of all piecewise-constant periodic orbits of an additive functional recurrence generalizing that present in the golden mean case. We establish a criterion for periodic orbits to be globally bounded, and also calculate the asymptotic height of the main peaks in the correlation function

  14. On Two-Level State-Dependent Routing Polling Systems with Mixed Service

    Directory of Open Access Journals (Sweden)

    Guan Zheng

    2015-01-01

    Full Text Available Based on priority differentiation and efficiency of the system, we consider an N+1 queues’ single-server two-level polling system which consists of one key queue and N normal queues. The novel contribution of the present paper is that we consider that the server just polls active queues with customers waiting in the queue. Furthermore, key queue is served with exhaustive service and normal queues are served with 1-limited service in a parallel scheduling. For this model, we derive an expression for the probability generating function of the joint queue length distribution at polling epochs. Based on these results, we derive the explicit closed-form expressions for the mean waiting time. Numerical examples demonstrate that theoretical and simulation results are identical and the new system is efficient both at key queue and normal queues.

  15. Detuning-induced stimulated Raman adiabatic passage in dense two-level systems

    Science.gov (United States)

    Deng, Li; Lin, Gongwei; Niu, Yueping; Gong, Shangqing

    2018-05-01

    We investigate the coherence generation in dense two-level systems under detuning-induced stimulated Raman adiabatic passage (D-STIRAP). In the dense two-level system, the near dipole-dipole (NDD) interaction should be taken into consideration. With the increase in the strength of the NDD interaction, it is found that a switchlike transition of the generated coherence from maximum value to zero appears. Meanwhile, the adiabatic condition of the D-STIRAP is destroyed in the presence of the NDD interaction. In order to avoid the sudden decrease in the generated coherence and maintain the maximum value, we can use stronger detuning pulse or pump pulse, between which increasing the intensity of the detuning pulse is of more efficiency. Except for taking advantage of such maximum coherence in the high density case into areas like enhancing the four-wave mixing process, we also point out that the phenomenon of the coherence transition can be applied as an optical switch.

  16. Amplification without inversion, fast light and optical bistability in a duplicated two-level system

    International Nuclear Information System (INIS)

    Ebrahimi Zohravi, Lida; Vafafard, Azar; Mahmoudi, Mohammad

    2014-01-01

    The optical properties of a weak probe field in a duplicated two-level system are investigated in multi-photon resonance (MPR) condition and beyond it. It is shown that by changing the relative phase of applied fields, the absorption switches to the amplification without inversion in MPR condition. By applying the Floquet decomposition to the equations of motion beyond MPR condition, it is shown that the phase-dependent behavior is valid only in MPR condition. Moreover, it is demonstrated that the group velocity of light pulse can be controlled by the intensity of the applied fields and the gain-assisted superluminal light propagation (fast light) is obtained in this system. In addition, the optical bistability (OB) behavior of the system is studied beyond MPR condition. We apply an indirect incoherent pumping field to the system and it is found that the group velocity and OB behavior of the system can be controlled by the incoherent pumping rate. - Highlights: • We studied the optical properties of DTL system under MPR condition and beyond it. • By changing the relative phase, the absorption switches to the amplification without inversion in MPR condition. • The gain-assisted superluminal light propagation (fast light) is obtained in this system. • The optical bistability (OB) behavior of the system is studied beyond MPR condition. • The incoherent pumping rate has a major role in controlling the group velocity and OB behavior of the system

  17. Two Level Versus Matrix Converters Performance in Wind Energy Conversion Systems Employing DFIG

    Science.gov (United States)

    Reddy, Gongati Pandu Ranga; Kumar, M. Vijaya

    2017-10-01

    Wind power capacity has received enormous growth during past decades. With substantial development of wind power, it is expected to provide a fifth of world's electricity by the end of 2030. In wind energy conversion system, the power electronic converters play an important role. This paper presents the two level and matrix converters performance in wind energy conversion system employing Doubly Fed Induction Generator (DFIG). The DFIG is a wound rotor induction generator. Because of the advantages of the DFIG over other generators it is being used for most of the wind applications. This paper also discusses control of converters using the space vector pulse width modulation technique. The MATLAB/SIMULINK ® software is used to study the performance of the converters.

  18. Dynamical Evolution of an Effective Two-Level System with {\\mathscr{P}}{\\mathscr{T}} Symmetry

    Science.gov (United States)

    Du, Lei; Xu, Zhihao; Yin, Chuanhao; Guo, Liping

    2018-05-01

    We investigate the dynamics of parity- and time-reversal (PT ) symmetric two-energy-level atoms in the presence of two optical and a radio-frequency (rf) fields. The strength and relative phase of fields can drive the system from unbroken to broken PT symmetric regions. Compared with the Hermitian model, Rabi-type oscillation is still observed, and the oscillation characteristics are also adjusted by the strength and relative phase in the region of unbroken PT symmetry. At exception point (EP), the oscillation breaks down. To better understand the underlying properties we study the effective Bloch dynamics and find the emergence of the z components of the fixed points is the feature of the PT symmetry breaking and the projections in x-y plane can be controlled with high flexibility compared with the standard two-level system with PT symmetry. It helps to study the dynamic behavior of the complex PT symmetric model.

  19. Faithful state transfer between two-level systems via an actively cooled finite-temperature cavity

    Science.gov (United States)

    Sárkány, Lőrinc; Fortágh, József; Petrosyan, David

    2018-03-01

    We consider state transfer between two qubits—effective two-level systems represented by Rydberg atoms—via a common mode of a microwave cavity at finite temperature. We find that when both qubits have the same coupling strength to the cavity field, at large enough detuning from the cavity mode frequency, quantum interference between the transition paths makes the swap of the excitation between the qubits largely insensitive to the number of thermal photons in the cavity. When, however, the coupling strengths are different, the photon-number-dependent differential Stark shift of the transition frequencies precludes efficient transfer. Nevertheless, using an auxiliary cooling system to continuously extract the cavity photons, we can still achieve a high-fidelity state transfer between the qubits.

  20. Dynamical model of coherent circularly polarized optical pulse interactions with two-level quantum systems

    International Nuclear Information System (INIS)

    Slavcheva, G.; Hess, O.

    2005-01-01

    We propose and develop a method for theoretical description of circularly (elliptically) polarized optical pulse resonant coherent interactions with two-level atoms. The method is based on the time-evolution equations of a two-level quantum system in the presence of a time-dependent dipole perturbation for electric dipole transitions between states with total angular-momentum projection difference (ΔJ z =±1) excited by a circularly polarized electromagnetic field [Feynman et al., J. Appl. Phys. 28, 49 (1957)]. The adopted real-vector representation approach allows for coupling with the vectorial Maxwell's equations for the optical wave propagation and thus the resulting Maxwell pseudospin equations can be numerically solved in the time domain without any approximations. The model permits a more exact study of the ultrafast coherent pulse propagation effects taking into account the vector nature of the electromagnetic field and hence the polarization state of the optical excitation. We demonstrate self-induced transparency effects and formation of polarized solitons. The model represents a qualitative extension of the well-known optical Maxwell-Bloch equations valid for linearly polarized light and a tool for studying coherent quantum control mechanisms

  1. Transmission-line resonators for the study of individual two-level tunneling systems

    Science.gov (United States)

    Brehm, Jan David; Bilmes, Alexander; Weiss, Georg; Ustinov, Alexey V.; Lisenfeld, Jürgen

    2017-09-01

    Parasitic two-level tunneling systems (TLS) emerge in amorphous dielectrics and constitute a serious nuisance for various microfabricated devices, where they act as a source of noise and decoherence. Here, we demonstrate a new test bed for the study of TLS in various materials which provides access to properties of individual TLS as well as their ensemble response. We terminate a superconducting transmission-line resonator with a capacitor that hosts TLS in its dielectric. By tuning TLS via applied mechanical strain, we observe the signatures of individual TLS strongly coupled to the resonator in its transmission characteristics and extract the coupling components of their dipole moments and energy relaxation rates. The strong and well-defined coupling to the TLS bath results in pronounced resonator frequency fluctuations and excess phase noise, through which we can study TLS ensemble effects such as spectral diffusion, and probe theoretical models of TLS interactions.

  2. Dynamics of a quantum two-level system under the action of phase-diffusion field

    Energy Technology Data Exchange (ETDEWEB)

    Sobakinskaya, E.A. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Pankratov, A.L., E-mail: alp@ipm.sci-nnov.ru [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Vaks, V.L. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation)

    2012-01-09

    We study a behavior of quantum two-level system, interacting with noisy phase-diffusion field. The dynamics is shown to split into two regimes, determined by the coherence time of the phase-diffusion field. For both regimes we present a model of quantum system behavior and discuss possible applications of the obtained effect for spectroscopy. In particular, the obtained analytical formula for the macroscopic polarization demonstrates that the phase-diffusion field does not affect the absorption line shape, which opens up an intriguing possibility of noisy spectroscopy, based on broadband sources with Lorentzian line shape. -- Highlights: ► We study dynamics of quantum system interacting with noisy phase-diffusion field. ► At short times the phase-diffusion field induces polarization in the quantum system. ► At long times the noise leads to polarization decay and heating of a quantum system. ► Simple model of interaction is derived. ► Application of the described effects for spectroscopy is discussed.

  3. A Two-Level Task Scheduler on Multiple DSP System for OpenCL

    Directory of Open Access Journals (Sweden)

    Li Tian

    2014-04-01

    Full Text Available This paper addresses the problem that multiple DSP system does not support OpenCL programming. With the compiler, runtime, and the kernel scheduler proposed, an OpenCL application becomes portable not only between multiple CPU and GPU, but also between embedded multiple DSP systems. Firstly, the LLVM compiler was imported for source-to-source translation in which the translated source was supported by CCS. Secondly, two-level schedulers were proposed to support efficient OpenCL kernel execution. The DSP/BIOS is used to schedule system level tasks such as interrupts and drivers; however, the synchronization mechanism resulted in heavy overhead during task switching. So we designed an efficient second level scheduler especially for OpenCL kernel work-item scheduling. The context switch process utilizes the 8 functional units and cross path links which was superior to DSP/BIOS in the aspect of task switching. Finally, dynamic loading and software managed CACHE were redesigned for OpenCL running on multiple DSP system. We evaluated the performance using some common OpenCL kernels from NVIDIA, AMD, NAS, and Parboil benchmarks. Experimental results show that the DSP OpenCL can efficiently exploit the computing resource of multiple cores.

  4. A distributed monitoring system for photovoltaic arrays based on a two-level wireless sensor network

    Science.gov (United States)

    Su, F. P.; Chen, Z. C.; Zhou, H. F.; Wu, L. J.; Lin, P. J.; Cheng, S. Y.; Li, Y. F.

    2017-11-01

    In this paper, a distributed on-line monitoring system based on a two-level wireless sensor network (WSN) is proposed for real time status monitoring of photovoltaic (PV) arrays to support the fine management and maintenance of PV power plants. The system includes the sensing nodes installed on PV modules (PVM), sensing and routing nodes installed on combiner boxes of PV sub-arrays (PVA), a sink node and a data management centre (DMC) running on a host computer. The first level WSN is implemented by the low-cost wireless transceiver nRF24L01, and it is used to achieve single hop communication between the PVM nodes and their corresponding PVA nodes. The second level WSN is realized by the CC2530 based ZigBee network for multi-hop communication among PVA nodes and the sink node. The PVM nodes are used to monitor the PVM working voltage and backplane temperature, and they send the acquired data to their PVA node via the nRF24L01 based first level WSN. The PVA nodes are used to monitor the array voltage, PV string current and environment irradiance, and they send the acquired and received data to the DMC via the ZigBee based second level WSN. The DMC is designed using the MATLAB GUIDE and MySQL database. Laboratory experiment results show that the system can effectively acquire, display, store and manage the operating and environment parameters of PVA in real time.

  5. Dynamical properties of a two-level system with arbitrary nonlinearities

    Indian Academy of Sciences (India)

    nication, information processing and quantum computing, such as in the investigation of quantum teleportation ... They con- sidered a two-level atom interacting with an undamped cavity initially in a coherent state. ... Because concurrence pro-.

  6. Acoustic interactions between inversion symmetric and asymmetric two-level systems

    International Nuclear Information System (INIS)

    Churkin, A; Schechter, M; Barash, D

    2014-01-01

    Amorphous solids, as well as many disordered lattices, display remarkable universality in their low temperature acoustic properties. This universality is attributed to the attenuation of phonons by tunneling two-level systems (TLSs), facilitated by the interaction of the TLSs with the phonon field. TLS-phonon interaction also mediates effective TLS–TLS interactions, which dictates the existence of a glassy phase and its low energy properties. Here we consider KBr:CN, the archetypal disordered lattice showing universality. We calculate numerically, using conjugate gradients method, the effective TLS–TLS interactions for inversion symmetric (CN flips) and asymmetric (CN rotations) TLSs, in the absence and presence of disorder, in two and three dimensions. The observed dependence of the magnitude and spatial power law of the interaction on TLS symmetry, and its change with disorder, characterizes TLS–TLS interactions in disordered lattices in both extreme and moderate dilutions. Our results are in good agreement with the two-TLS model, recently introduced to explain long-standing questions regarding the quantitative universality of phonon attenuation and the energy scale of ≈1–3 K below which universality is observed. (paper)

  7. Quasiparticle-induced decoherence of microscopic two-level-systems in superconducting qubits

    Energy Technology Data Exchange (ETDEWEB)

    Bilmes, Alexander; Lisenfeld, Juergen; Zanker, Sebastian; Weiss, Georg; Ustinov, Alexey V. [PHI, KIT, Karlsruhe (Germany); Marthaler, Michael; Schoen, Gerd [TFP, KIT, Karlsruhe (Germany)

    2016-07-01

    Parasitic Two-Level-Systems (TLS) are one of the main sources of decoherence in superconducting nano-scale devices such as SQUIDs, resonators and quantum bits (qubits), although the TLS' microscopic nature remains unclear. We use a superconducting phase qubit to detect TLS contained within the tunnel barrier of the qubit's Al/AlOx/Al Josephson junction. If the TLS transition frequency lies within the 6-10 GHz range, we can coherently drive it by resonant microwave pulses and access its quantum state by utilizing the strong coupling to the qubit. Our previous measurements of TLS coherence in dependence of the temperature indicate that quasiparticles (QPs), which diffuse from the superconducting Al electrodes into the oxide layer, may give rise to TLS energy loss and dephasing. Here, we probe the TLS-QP interaction using a reliable method of in-situ QP injection via an on-chip dc-SQUID that is pulse-biased beyond its switching current. The QP density is calibrated by measuring associated characteristic changes to the qubit's energy relaxation rate. We will present experimental data which show the QP-induced TLS decoherence in good agreement to theoretical predictions.

  8. Crises-induced intermittencies in a coherently driven system of two-level atoms

    International Nuclear Information System (INIS)

    Pando L, C.L.; Perez, G.; Cerdeira, H.A.

    1993-04-01

    We study the coherent dynamics of a thin layer of two-level atoms driven by an external coherent field and a phase conjugated mirror (PCM). Since the variables of the system are defined on the Bloch sphere, the third dimension is provided by the temporal modulation of the Rabi frequencies, which are induced by a PCM which reflects an electric field with a carrier frequency different from the incident one. We show that as the PCM gain coefficient is changed period doubling leading to chaos occurs. We find crises of attractor merging and attractor widening types related to homoclinic and heteroclinic tangencies respectively. For the attractor merging crises we find the critical exponent for the characteristic time of intermittency versus the control parameter which is given by the gain coefficient of the PCM. We show that during the crises of attractor widening type, another crisis due to attractor destruction occurs as the control parameter is changed. The latter is due to the collision of the old attractor with its basin boundary when a new attractor is created. This new attractor is stable only in a very small interval in the neighborhood of this second crisis. (author). 31 refs, 15 figs

  9. Two levels decision system for efficient planning and implementation of bioenergy production

    International Nuclear Information System (INIS)

    Ayoub, Nasser; Martins, Ricardo; Wang, Kefeng; Seki, Hiroya; Naka, Yuji

    2007-01-01

    When planning bioenergy production from biomass, planners should take into account each and every stakeholder along the biomass supply chains, e.g. biomass resources suppliers, transportation, conversion and electricity suppliers. Also, the planners have to consider social concerns, environmental and economical impacts related with establishing the biomass systems and the specific difficulties of each country. To overcome these problems in a sustainable manner, a robust decision support system is required. For that purpose, a two levels general Bioenergy Decision System (gBEDS) for bioenergy production planning and implementation was developed. The core part of the gBEDS is the information base, which includes the basic bioenergy information and the detailed decision information. Basic bioenergy information include, for instance, the geographical information system (GIS) database, the biomass materials' database, the biomass logistic database and the biomass conversion database. The detailed decision information considers the parameters' values database with their default values and the variables database, values obtained by simulation and optimization. It also includes a scenario database, which is used for demonstration to new users and also for case based reasoning by planners and executers. Based on the information base, the following modules are included to support decision making: the simulation module with graph interface based on the unit process (UP) definition and the genetic algorithms (GAs) methods for optimal decisions and the Matlab module for applying data mining methods (fuzzy C-means clustering and decision trees) to the biomass collection points, to define the location of storage and bioenergy conversion plants based on the simulation and optimization model developed of the whole life cycle of bioenergy generation. Furthermore, Matlab is used to set up a calculation model with crucial biomass planning parameters (e.g. costs, CO 2 emissions), over

  10. Analysis of Two-Level Support Systems with Time-Dependent Overflow - A Banking Application

    DEFF Research Database (Denmark)

    Barth, Wolfgang; Manitz, Michael; Stolletz, Raik

    2010-01-01

    In this paper, we analyze the performance of call centers of financial service providers with two levels of support and a time-dependent overflow mechanism. Waiting calls from the front-office queue flow over to the back office if a waiting-time limit is reached and at least one back-office agent...

  11. Open quantum systems and the two-level atom interacting with a single mode of the electromagnetic field

    International Nuclear Information System (INIS)

    Sandulescu, A.; Stefanescu, E.

    1987-07-01

    On the basis of Lindblad theory of open quantum systems we obtain new optical equations for the system of two-level atom interacting with a single mode of the electromagnetic field. The conventional Block equations in a generalized form with field phases are obtained in the hypothesis that all the terms are slowly varying in the rotating frame.(authors)

  12. Method and system for in vivo measurement of bone tissue using a two level energy source

    Science.gov (United States)

    Cameron, J. R.; Judy, P. F. (Inventor)

    1976-01-01

    Methods and apparatus are provided for radiologically determining the bone mineral content of living human bone tissue independently of the concurrent presence of adipose and other soft tissues. A target section of the body of the subject is irradiated with a beam of penetrative radiations of preselected energy to determine the attenuation of such beam with respect to the intensity of each of two radiations of different predetermined energy levels. The resulting measurements are then employed to determine bone mineral content.

  13. Quantum driving protocols for a two-level system: From generalized Landau-Zener sweeps to transitionless control

    DEFF Research Database (Denmark)

    Malossi, Nicola; Bason, Mark George; Viteau, Matthieu

    2013-01-01

    We present experimental results on the preparation of a desired quantum state in a two-level system with the maximum possible fidelity using driving protocols ranging from generalizations of the linear Landau-Zener protocol to transitionless driving protocols that ensure perfect following of the ...

  14. Method and system for in vivo measurement of bone tissue using a two level energy source

    International Nuclear Information System (INIS)

    Fletcher, J.C.; Cameron, J.R.; Judy, P.F.

    1976-01-01

    Methods and apparatus are provided for radiologically determining the bone mineral content of living human bone tissue independently of the concurrent presence of adipose and other soft tissues. A target section of the body of the subject is irradiated with a beam of penetrative radiations of preselected energy to determine the attenuation of such beam with respect to the intensity of each of two radiations of different predetermined energy levels. The resulting measurements are then employed to determine bone mineral content according to the following relationship: I = (I 0 ) exp [(μBM/sup M/BM) - (μST/sup M/ST)] wherein I 0 is the unattentuated intensity of the radiations in the beam, μ is the mass attenuation coefficient, M is mass in g/cm 2

  15. Organization of the two-level memory in the image processing system on scanning measuring projectors

    International Nuclear Information System (INIS)

    Sychev, A.Yu.

    1977-01-01

    Discussed are the problems of improving the efficiency of the system for processing pictures taken in bubble chambers with the use of scanning measuring projectors. The system comprises 20 to 30 pro ectors linked with the ICL-1903A computer provided with a mainframe memory, 64 kilobytes in size. Because of the insufficient size of a mainframe memory, a part of the programs and data is located in a second-level memory, i.e. in an external memory. The analytical model described herein is used to analyze the effect of the memory organization on the characteristics of the system. It is shown that organization of pure procedures and introduction of the centralized control of the tWo-leVel memory result in substantial improvement of the efficiency of the picture processing system

  16. Optimization of Two-Level Disassembly/Remanufacturing/Assembly System with an Integrated Maintenance Strategy

    Directory of Open Access Journals (Sweden)

    Zouhour Guiras

    2018-04-01

    Full Text Available With an increase of environmental pressure on economic activities, reverse flow is increasingly important. It seeks to save resources, eliminate waste, and improve productivity. This paper investigates the optimization of the disassembly, remanufacturing and assembly system, taking into account assembly-disassembly system degradation. An analytical model is developed to consider disassembly, remanufacturing of used/end-of-life product and assembly of the finished product. The finished product is composed of remanufactured and new components. A maintenance policy is sequentially integrated to reduce the system unavailability. The aim of this study is to help decision-makers, under certain conditions, choose the most cost-effective process for them to satisfy the customer as well as to adapt to the potential risk that can perturb the disassembly-assembly system. A heuristic is developed to determine the optimal ordered date of the used end-of-life product as well as the optimum release dates of new external components. The results reveal that considering some remanufacturing and purchase components costs, the proposed model is more economical in comparison with a model without remanufactured parts. Numerical results are provided to illustrate the impact of the variation of the ordering cost and quality of the used end-of-life product on the system profitability. Finally, the risk due to system repair periods is discussed, which has an impact on managerial decision-making.

  17. Information systems performance evaluation, introducing a two-level technique: Case study call centers

    Directory of Open Access Journals (Sweden)

    Hesham A. Baraka

    2015-03-01

    The objective of this paper was to introduce a new technique that can support decision makers in the call centers industry to evaluate, and analyze the performance of call centers. The technique presented is derived from the research done on measuring the success or failure of information systems. Two models are mainly adopted namely: the Delone and Mclean model first introduced in 1992 and the Design Reality Gap model introduced by Heeks in 2002. Two indices are defined to calculate the performance of the call center; the success index and the Gap Index. An evaluation tool has been developed to allow call centers managers to evaluate the performance of their call centers in a systematic analytical approach; the tool was applied on 4 call centers from different areas, simple applications such as food ordering, marketing, and sales, technical support systems, to more real time services such as the example of emergency control systems. Results showed the importance of using information systems models to evaluate complex systems as call centers. The models used allow identifying the dimensions for the call centers that are facing challenges, together with an identification of the individual indicators in these dimensions that are causing the poor performance of the call center.

  18. On irreversible evolutions of two-level systems approaching coherent and squeezed states

    International Nuclear Information System (INIS)

    Jurco, B.; Tolar, J.

    1988-01-01

    The concepts of completely positive quantum dynamical semigroups and SU(2)-related generalized coherence and squeezing are used to investigate conditions for Markovian evolutions leading to coherent, intelligent, minimum-uncertainty and squeezed asymptotic stationary states in a 2-level system. (author). 10 refs

  19. Two-Level Control for Fast Electrical Vehicle Charging Stations with Multi Flywheel Energy Storage System

    DEFF Research Database (Denmark)

    SUN, BO; Dragicevic, Tomislav; Vasquez, Juan Carlos

    2015-01-01

    This paper applies a hierarchical control for a fast charging station (FCS) composed of paralleled PWM rectifier and dedicated paralleled multiple flywheel energy storage systems (FESSs), in order to mitigate peak power shock on grid caused by sudden connection of electrical vehicle (EV) chargers...

  20. Adiabatic passage for a lossy two-level quantum system by a complex time method

    International Nuclear Information System (INIS)

    Dridi, G; Guérin, S

    2012-01-01

    Using a complex time method with the formalism of Stokes lines, we establish a generalization of the Davis–Dykhne–Pechukas formula which gives in the adiabatic limit the transition probability of a lossy two-state system driven by an external frequency-chirped pulse-shaped field. The conditions that allow this generalization are derived. We illustrate the result with the dissipative Allen–Eberly and Rosen–Zener models. (paper)

  1. Minimax approach problem with incomplete information for the two-level hierarchical discrete-time dynamical system

    Energy Technology Data Exchange (ETDEWEB)

    Shorikov, A. F. [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002, Russia and Institute of Mathematics and Mechanics, Ural Division of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation)

    2014-11-18

    We consider a discrete-time dynamical system consisting of three controllable objects. The motions of all objects are given by the corresponding vector linear or convex discrete-time recurrent vector relations, and control system for its has two levels: basic (first or I level) that is dominating and subordinate level (second or II level) and both have different criterions of functioning and united a priori by determined informational and control connections defined in advance. For the dynamical system in question, we propose a mathematical formalization in the form of solving a multistep problem of two-level hierarchical minimax program control over the terminal approach process with incomplete information and give a general scheme for its solution.

  2. Geometric phase for a two-level system in photonic band gab crystal

    Science.gov (United States)

    Berrada, K.

    2018-05-01

    In this work, we investigate the geometric phase (GP) for a qubit system coupled to its own anisotropic and isotropic photonic band gap (PBG) crystal environment without Born or Markovian approximation. The qubit frequency affects the GP of the qubit directly through the effect of the PBG environment. The results show the deviation of the GP depends on the detuning parameter and this deviation will be large for relatively large detuning of atom frequency inside the gap with respect to the photonic band edge. Whereas for detunings outside the gap, the GP of the qubit changes abruptly to zero, exhibiting collapse phenomenon of the GP. Moreover, we find that the GP in the isotropic PBG photonic crystal is more robust than that in the anisotropic PBG under the same condition. Finally, we explore the relationship between the variation of the GP and population in terms of the physical parameters.

  3. Modelling thermionic emission by using a two-level mechanical system

    International Nuclear Information System (INIS)

    Battaglia, O.R.

    2008-01-01

    The Boltzmann factor is at the basis of a great amount of thermodynamic and statistical physics, both classical and quantum. It describes the behaviour of natural systems that exchange energy with the environment. However, why does the expression have that specific form? The Feynman Lectures on Physics justifies it heuristically by referencing to the exponential atmosphere example. Thermodynamics textbooks usually give a more or less complete explanation that mainly involves a mathematical analysis, where it is hard to see the logic flow. Moreover, the necessary mathematics is not at the level of high school or college students' preparation. Here we present an experiment and a simulation at deriving the Boltzmann factor expression and illustrating the fundamental concepts and principles of statistical mechanics. Experiments and simulations are used in order to visualise the mechanism involved; the experiments use easily available laboratory equipment, and simulations are developed in Net Logo, a software environment that, besides having a really friendly interface, allows the user to easily interact with the algorithm, as well as to modify it.

  4. Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields

    Energy Technology Data Exchange (ETDEWEB)

    Puthumpally-Joseph, Raiju; Charron, Eric [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Sukharev, Maxim [Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University, Mesa, Arizona 85212 (United States)

    2016-04-21

    We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.

  5. Entropy as a measure of the noise extent in a two-level quantum feedback controlled system

    Institute of Scientific and Technical Information of China (English)

    Wang Tao-Bo; Fang Mao-Fa; Hu Yao-Hua

    2007-01-01

    By introducing the von Neumann entropy as a measure of the extent of noise, this paper discusses the entropy evolution in a two-level quantum feedback controlled system. The results show that the feedback control can induce the reduction of the degree of noise, and different control schemes exhibit different noise controlling ability, the extent of the reduction also related with the position of the target state on the Bloch sphere. It is shown that the evolution of entropy can provide a real time noise observation and a systematic guideline to make reasonable choice of control strategy.

  6. Comparison of PI and PR current controllers applied on two-level VSC-HVDC transmission system

    DEFF Research Database (Denmark)

    Manoloiu, A.; Pereria, H.A.; Teodorescu, Remus

    2015-01-01

    This paper analyzes differences between αβ and dq reference frames regarding the control of two-level VSC-HVDC current loop and dc-link voltage outer loop. In the first part, voltage feedforward effect is considered with PI and PR controllers. In the second part, the feedforward effect is removed...... and the PR gains are tuned to keep the dynamic performance. Also, the power feedforward is removed and the outer loop PI controller is tuned in order to maintain the system dynamic performance. The paper is completed with simulation results, which highlight the advantages of using PR controller....

  7. Experimental study of magnetocaloric effect in the two-level quantum system KTm(MoO4)2

    Science.gov (United States)

    Tarasenko, R.; Tkáč, V.; Orendáčová, A.; Orendáč, M.; Valenta, J.; Sechovský, V.; Feher, A.

    2018-05-01

    KTm(MoO4)2 belongs to the family of binary alkaline rare-earth molybdates. This compound can be considered to be an almost ideal quantum two-level system at low temperatures. Magnetocaloric properties of KTm(MoO4)2 single crystals were investigated using specific heat and magnetization measurement in the magnetic field applied along the easy axis. Large conventional magnetocaloric effect (-ΔSM ≈ 10.3 J/(kg K)) was observed in the magnetic field of 5 T in a relatively wide temperature interval. The isothermal magnetic entropy change of about 8 J/(kgK) has been achieved already for the magnetic field of 2 T. Temperature dependence of the isothermal entropy change under different magnetic fields is in good agreement with theoretical predictions for a quantum two-level system with Δ ≈ 2.82 cm-1. Investigation of magnetocaloric properties of KTm(MoO4)2 suggests that the studied system can be considered as a good material for magnetic cooling at low temperatures.

  8. Optimal control of quantum gates and suppression of decoherence in a system of interacting two-level particles

    International Nuclear Information System (INIS)

    Grace, Matthew; Brif, Constantin; Rabitz, Herschel; Walmsley, Ian A; Kosut, Robert L; Lidar, Daniel A

    2007-01-01

    Methods of optimal control are applied to a model system of interacting two-level particles (e.g., spin-half atomic nuclei or electrons or two-level atoms) to produce high-fidelity quantum gates while simultaneously negating the detrimental effect of decoherence. One set of particles functions as the quantum information processor, whose evolution is controlled by a time-dependent external field. The other particles are not directly controlled and serve as an effective environment, coupling to which is the source of decoherence. The control objective is to generate target one- and two-qubit unitary gates in the presence of strong environmentally-induced decoherence and under physically motivated restrictions on the control field. The quantum-gate fidelity, expressed in terms of a novel state-independent distance measure, is maximized with respect to the control field using combined genetic and gradient algorithms. The resulting high-fidelity gates demonstrate the feasibility of precisely guiding the quantum evolution via optimal control, even when the system complexity is exacerbated by environmental coupling. It is found that the gate duration has an important effect on the control mechanism and resulting fidelity. An analysis of the sensitivity of the gate performance to random variations in the system parameters reveals a significant degree of robustness attained by the optimal control solutions

  9. Design of a Two-level Adaptive Multi-Agent System for Malaria Vectors driven by an ontology

    Directory of Open Access Journals (Sweden)

    Etang Josiane

    2007-07-01

    Full Text Available Abstract Background The understanding of heterogeneities in disease transmission dynamics as far as malaria vectors are concerned is a big challenge. Many studies while tackling this problem don't find exact models to explain the malaria vectors propagation. Methods To solve the problem we define an Adaptive Multi-Agent System (AMAS which has the property to be elastic and is a two-level system as well. This AMAS is a dynamic system where the two levels are linked by an Ontology which allows it to function as a reduced system and as an extended system. In a primary level, the AMAS comprises organization agents and in a secondary level, it is constituted of analysis agents. Its entry point, a User Interface Agent, can reproduce itself because it is given a minimum of background knowledge and it learns appropriate "behavior" from the user in the presence of ambiguous queries and from other agents of the AMAS in other situations. Results Some of the outputs of our system present a series of tables, diagrams showing some factors like Entomological parameters of malaria transmission, Percentages of malaria transmission per malaria vectors, Entomological inoculation rate. Many others parameters can be produced by the system depending on the inputted data. Conclusion Our approach is an intelligent one which differs from statistical approaches that are sometimes used in the field. This intelligent approach aligns itself with the distributed artificial intelligence. In terms of fight against malaria disease our system offers opportunities of reducing efforts of human resources who are not obliged to cover the entire territory while conducting surveys. Secondly the AMAS can determine the presence or the absence of malaria vectors even when specific data have not been collected in the geographical area. In the difference of a statistical technique, in our case the projection of the results in the field can sometimes appeared to be more general.

  10. Quantum correlations between each two-level system in a pair of atoms and general coherent fields

    Directory of Open Access Journals (Sweden)

    S. Abdel-Khalek

    Full Text Available The quantitative description of the quantum correlations between each two-level system in a two-atom system and the coherent fields initially defined in a coherent state in the framework of power-law potentials (PLPCSs is considered. Specifically, we consider two atoms locally interacting with PLPCSs and take into account the different terms of interactions, the entanglement and quantum discord are studied including the time-dependent coupling and photon transition effects. Using the monogamic relation between the entanglement of formation and quantum discord in tripartite systems, we show that the control and preservation of the different kinds of quantum correlations greatly benefit from the combination of the choice of the physical quantities. Finally, we explore the link between the dynamical behavior of quantum correlations and nonclassicality of the fields with and without atomic motion effect. Keywords: Quantum correlations, Monogamic relation, Coherent states, Power-law potentials, Wehrl entropy

  11. Dynamics of a Landau-Zener transitions in a two-level system driven by a dissipative environment

    Science.gov (United States)

    Ateuafack, M. E.; Diffo, J. T.; Fai, L. C.

    2016-02-01

    The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.

  12. Dynamics of a Landau–Zener transitions in a two-level system driven by a dissipative environment

    Energy Technology Data Exchange (ETDEWEB)

    Ateuafack, M.E., E-mail: esouamath@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Diffo, J.T., E-mail: diffojaures@yahoo.com [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon); Department of Physics, Higher Teachers' Training College, The University of Maroua, PO Box 55 Maroua (Cameroon); Fai, L.C., E-mail: corneliusfai@yahoo.fr [Mesoscopic and Multilayer Structures Laboratory, Department of Physics, Faculty of Science, University of Dschang (Cameroon)

    2016-02-15

    The paper investigates the effects of a two-level quantum system coupled to transversal and longitudinal dissipative environment. The time-dependent phase accumulation, LZ transition probability and entropy in the presence of fast-ohmic, sub-ohmic and super-ohmic quantum noise are derived. Analytical results are obtained in terms of temperature, dissipation strength, LZ parameter and bath cutoff frequency. The bath is observed to modify the standard occupation difference by a decaying random phase factor and also produces dephasing during the transfer of population. The dephasing characteristics or the initial non-zero decoherence rate are observed to increase in time with the bath temperature and depend on the system-bath coupling strength and cutoff frequency. These parameters are found to strongly affect the memory and thus tailor the coherence process of the system.

  13. A Two-Level Sensorless MPPT Strategy Using SRF-PLL on a PMSG Wind Energy Conversion System

    Directory of Open Access Journals (Sweden)

    Amina Echchaachouai

    2017-01-01

    Full Text Available In this paper, a two-level sensorless Maximum Power Point Tracking (MPPT strategy is presented for a variable speed Wind Energy Conversion System (WECS. The proposed system is composed of a wind turbine, a direct-drive Permanent Magnet Synchronous Generator (PMSG and a three phase controlled rectifier connected to a DC load. The realised generator output power maximization analysis justifies the use of the Field Oriented Control (FOC giving the six Pulse Width Modulation (PWM signals to the active rectifier. The generator rotor speed and position required by the FOC and the sensorless MPPT are estimated using a Synchronous Reference Frame Phase Locked Loop (SRF-PLL. The MPPT strategy used consists of two levels, the first level is a power regulation loop and the second level is an extremum seeking bloc generating the coefficient gathering the turbine characteristics. Experimental results validated on a hardware test setup using a DSP digital board (dSPACE 1104 are presented. Figures illustrating the estimated speed and angle confirm that the SRF-PLL is able to give an estimated speed and angle which closely follow the real ones. Also, the power at the DC load and the power at the generator output indicate that the MPPT gives optimum extracted power. Finally, other results show the effectiveness of the adopted approach in real time applications.

  14. Transverse magnetic field effect on the giant Goos–Hänchen shifts based on a degenerate two-level system

    Science.gov (United States)

    Nasehi, R.

    2018-06-01

    We study the effect of the Goos–Hänchen (GH) shifts through a cavity with degenerate two-level systems in the line of . For this purpose, we focus on the transverse magnetic field (TMF) in a Floquet frame to obtain the giant GH shifts. Physically, the collisional effects of TMF lead to increasing the population trapping in the ground state. However, we demonstrate that the population trapping generates the large negative or positive GH shifts and simultaneously switches from superluminal to subluminal (or vice versa). Also, we investigate the other optical properties such as the longitudinal magnetic field (LMF), which plays an important role in the control of the GH shifts and leads to the generation of new subsystems. In the next step, we evaluate the GH shifts beyond the multi-photon resonance condition by the control of TMF. Moreover, we compute the appearance of negative and positive GH shifts by setting the width of the incident Gaussian beams in the presence of a multi-photon resonance condition. Our results show that superluminal or subluminal light propagation can be simultaneously controlled by adjusting the rates of the TMF and LMF. The significant effects of these factors on the degenerate two-level systems provide different applications such as slow light, optical switches and quantum information storage.

  15. Quantum phase transition in a coupled two-level system embedded in anisotropic three-dimensional photonic crystals.

    Science.gov (United States)

    Shen, H Z; Shao, X Q; Wang, G C; Zhao, X L; Yi, X X

    2016-01-01

    The quantum phase transition (QPT) describes a sudden qualitative change of the macroscopic properties mapped from the eigenspectrum of a quantum many-body system. It has been studied intensively in quantum systems with the spin-boson model, but it has barely been explored for systems in coupled spin-boson models. In this paper, we study the QPT with coupled spin-boson models consisting of coupled two-level atoms embedded in three-dimensional anisotropic photonic crystals. The dynamics of the system is derived exactly by means of the Laplace transform method, which has been proven to be equivalent to the dissipationless non-Markovian dynamics. Drawing on methods for analyzing the ground state, we obtain the phase diagrams through two exact critical equations and two QPTs are found: one QPT is that from the phase without one bound state to the phase with one bound state and another is that from one phase with the bound state having one eigenvalue to another phase where the bound state has two eigenvalues. Our analytical results also suggest a way of control to overcome the effect of decoherence by engineering the spectrum of the reservoirs to approach the non-Markovian regime and to form the bound state of the whole system for quantum devices and quantum statistics.

  16. Quantum driving of a two level system: quantum speed limit and superadiabatic protocols – an experimental investigation

    International Nuclear Information System (INIS)

    Malossi, N; Arimondo, E; Ciampini, D; Mannella, R; Bason, M G; Viteau, M; Morsch, O

    2013-01-01

    A fundamental requirement in quantum information processing and in many other areas of science is the capability of precisely controlling a quantum system by preparing a quantum state with the highest fidelity and/or in the fastest possible way. Here we present an experimental investigation of a two level system, characterized by a time-dependent Landau-Zener Hamiltonian, aiming to test general and optimal high-fidelity control protocols. The experiment is based on a Bose-Einstein condensate (BEC) loaded into an optical lattice, then accelerated, which provides a high degree of control over the experimental parameters. We implement generalized Landau-Zener sweeps, comparing them with the well-known linear Landau-Zener sweep. We drive the system from an initial state to a final state with fidelity close to unity in the shortest possible time (quantum brachistochrone), thus reaching the ultimate speed limit imposed by quantum mechanics. On the opposite extreme of the quantum control spectrum, the aim is not to minimize the total transition time but to maximize the adiabaticity during the time-evolution, the system being constrained to the adiabatic ground state at any time. We implement such transitionless superadiabatic protocols by an appropriate transformation of the Hamiltonian parameters. This transformation is general and independent of the physical system.

  17. Statistical Analysis of the Figure of Merit of a Two-Level Thermoelectric System: A Random Matrix Approach

    KAUST Repository

    Abbout, Adel

    2016-08-05

    Using the tools of random matrix theory we develop a statistical analysis of the transport properties of thermoelectric low-dimensional systems made of two electron reservoirs set at different temperatures and chemical potentials, and connected through a low-density-of-states two-level quantum dot that acts as a conducting chaotic cavity. Our exact treatment of the chaotic behavior in such devices lies on the scattering matrix formalism and yields analytical expressions for the joint probability distribution functions of the Seebeck coefficient and the transmission profile, as well as the marginal distributions, at arbitrary Fermi energy. The scattering matrices belong to circular ensembles which we sample to numerically compute the transmission function, the Seebeck coefficient, and their relationship. The exact transport coefficients probability distributions are found to be highly non-Gaussian for small numbers of conduction modes, and the analytical and numerical results are in excellent agreement. The system performance is also studied, and we find that the optimum performance is obtained for half-transparent quantum dots; further, this optimum may be enhanced for systems with few conduction modes.

  18. Statistical Analysis of the Figure of Merit of a Two-Level Thermoelectric System: A Random Matrix Approach

    KAUST Repository

    Abbout, Adel; Ouerdane, Henni; Goupil, Christophe

    2016-01-01

    Using the tools of random matrix theory we develop a statistical analysis of the transport properties of thermoelectric low-dimensional systems made of two electron reservoirs set at different temperatures and chemical potentials, and connected through a low-density-of-states two-level quantum dot that acts as a conducting chaotic cavity. Our exact treatment of the chaotic behavior in such devices lies on the scattering matrix formalism and yields analytical expressions for the joint probability distribution functions of the Seebeck coefficient and the transmission profile, as well as the marginal distributions, at arbitrary Fermi energy. The scattering matrices belong to circular ensembles which we sample to numerically compute the transmission function, the Seebeck coefficient, and their relationship. The exact transport coefficients probability distributions are found to be highly non-Gaussian for small numbers of conduction modes, and the analytical and numerical results are in excellent agreement. The system performance is also studied, and we find that the optimum performance is obtained for half-transparent quantum dots; further, this optimum may be enhanced for systems with few conduction modes.

  19. Optomechanically induced transparency in multi-cavity optomechanical system with and without one two-level atom.

    Science.gov (United States)

    Sohail, Amjad; Zhang, Yang; Zhang, Jun; Yu, Chang-Shui

    2016-06-28

    We analytically study the optomechanically induced transparency (OMIT) in the N-cavity system with the Nth cavity driven by pump, probing laser fields and the 1st cavity coupled to mechanical oscillator. We also consider that one atom could be trapped in the ith cavity. Instead of only illustrating the OMIT in such a system, we are interested in how the number of OMIT windows is influenced by the cavities and the atom and what roles the atom could play in different cavities. In the resolved sideband regime, we find that, the number of cavities precisely determines the maximal number of OMIT windows. It is interesting that, when the two-level atom is trapped in the even-labeled cavity, the central absorptive peak (odd N) or dip (even N) is split and forms an extra OMIT window, but if the atom is trapped in the odd-labeled cavity, the central absorptive peak (odd N) or dip (even N) is only broadened and thus changes the width of the OMIT windows rather than induces an extra window.

  20. Cavity quantum electrodynamics using a near-resonance two-level system: Emergence of the Glauber state

    Energy Technology Data Exchange (ETDEWEB)

    Sarabi, B.; Ramanayaka, A. N. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Burin, A. L. [Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Wellstood, F. C. [Department of Physics, University of Maryland, College Park, Maryland 20742 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States); Osborn, K. D. [Laboratory for Physical Sciences, College Park, Maryland 20740 (United States); Joint Quantum Institute, University of Maryland, College Park, Maryland 20742 (United States)

    2015-04-27

    Random tunneling two-level systems (TLSs) in dielectrics have been of interest recently because they adversely affect the performance of superconducting qubits. The coupling of TLSs to qubits has allowed individual TLS characterization, which has previously been limited to TLSs within (thin) Josephson tunneling barriers made from aluminum oxide. Here, we report on the measurement of an individual TLS within the capacitor of a lumped-element LC microwave resonator, which forms a cavity quantum electrodynamics (CQED) system and allows for individual TLS characterization in a different structure and material than demonstrated with qubits. Due to the reduced volume of the dielectric (80 μm{sup 3}), even with a moderate dielectric thickness (250 nm), we achieve the strong coupling regime as evidenced by the vacuum Rabi splitting observed in the cavity spectrum. A TLS with a coherence time of 3.2 μs was observed in a film of silicon nitride as analyzed with a Jaynes-Cummings spectral model, which is larger than seen from superconducting qubits. As the drive power is increased, we observe an unusual but explicable set of continuous and discrete crossovers from the vacuum Rabi split transitions to the Glauber (coherent) state.

  1. Phase-controlled all-optical switching based on coherent population oscillation in a two-level system

    International Nuclear Information System (INIS)

    Liao, Ping; Yu, Song; Luo, Bin; Shen, Jing; Gu, Wanyi; Guo, Hong

    2011-01-01

    We theoretically propose a scheme of phase-controlled all-optical switching due to the effect of degenerate four-wave mixing (FWM) and coherent population oscillation (CPO) in a two-level system driven by a strong coupling field and two weak symmetrically detuned fields. The results show that the phase of the FWM field can be utilized to switch between constructive and destructive interference, which can lead to the transmission or attenuation of the probe field and thus switch the field on or off. We also find the intensity of the coupling field and the propagation distance have great influence on the performance of the switching. In our scheme, due to the quick response in semiconductor systems, a fast all-optical switching can be realized at low light level. -- Highlights: ► We study a new all-optical switching based on coherent population oscillation. ► The phase of the FWM field can be utilized to switch the probe field on or off. ► A fast and low-light-level switching can be realized in semiconductors.

  2. Dissipative two-level system under strong ac driving: A combination of Floquet and Van Vleck perturbation theory

    International Nuclear Information System (INIS)

    Hausinger, Johannes; Grifoni, Milena

    2010-01-01

    We study the dissipative dynamics of a two-level system (TLS) exposed to strong ac driving. By combining Floquet theory with Van Vleck perturbation theory in the TLS tunneling matrix element, we diagonalize the time-dependent Hamiltonian and provide corrections to the renormalized Rabi frequency of the TLS, which are valid for both a biased and unbiased TLS and go beyond the known high-frequency and rotating-wave results. In order to mimic environmental influences on the TLS, we couple the system weakly to a thermal bath and solve analytically the corresponding Floquet-Bloch-Redfield master equation. We give a closed expression for the relaxation and dephasing rates of the TLS and discuss their behavior under variation of the driving amplitude. Further, we examine the robustness of coherent destruction of tunneling (CDT) and driving-induced tunneling oscillations (DITO). We show that also for a moderate driving frequency an almost complete suppression of tunneling can be achieved for short times and demonstrate the sensitiveness of DITO to a change of the external parameters.

  3. Quantum theory of phonon-mediated decoherence and relaxation of two-level systems in a structured electromagnetic reservoir

    Science.gov (United States)

    Roy, Chiranjeeb

    In this thesis we study the role of nonradiative degrees of freedom on quantum optical properties of mesoscopic quantum dots placed in the structured electromagnetic reservoir of a photonic crystal. We derive a quantum theory of the role of acoustic and optical phonons in modifying the optical absorption lineshape, polarization dynamics, and population dynamics of a two-level atom (quantum dot) in the "colored" electromagnetic vacuum of a photonic band gap (PBG) material. This is based on a microscopic Hamiltonian describing both radiative and vibrational processes quantum mechanically. Phonon sidebands in an ordinary electromagnetic reservoir are recaptured in a simple model of optical phonons using a mean-field factorization of the atomic and lattice displacement operators. Our formalism is then used to treat the non-Markovian dynamics of the same system within the structured electromagnetic density of states of a photonic crystal. We elucidate the extent to which phonon-assisted decay limits the lifetime of a single photon-atom bound state and derive the modified spontaneous emission dynamics due to coupling to various phonon baths. We demonstrate that coherent interaction with undamped phonons can lead to enhanced lifetime of a photon-atom bound state in a PBG by (i) dephasing and reducing the transition electric dipole moment of the atom and (ii) reducing the quantum mechanical overlap of the state vectors of the excited and ground state (polaronic shift). This results in reduction of the steady-state atomic polarization but an increase in the fractionalized upper state population in the photon-atom bound state. We demonstrate, on the other hand, that the lifetime of the photon-atom bound state in a PBG is limited by the lifetime of phonons due to lattice anharmonicities (break-up of phonons into lower energy phonons) and purely nonradiative decay. We demonstrate how these additional damping effects limit the extent of the polaronic (Franck-Condon) shift of

  4. On the deviation from the sech2 superradiant emission law in a two-level atomic system

    International Nuclear Information System (INIS)

    Goncalves, A.E.

    1990-01-01

    The atomic superradiant emission is treated in the single particle mean field approximation. A single particle Hamiltonian, which represents a dressed two-level atom in a radiation field, can be obtained and it is verified that it describes the transient regime of the emission process. While the line shape emission for a bare atom follows the sech 2 law, for the dressed atom the line shape deviates appreciably from this law and it is verified that the deviation depends crucially on the ratio of the dynamic frequency shift to the transition frequency. This kind of deviation is observed in experimental results. (Author) [pt

  5. Effects of phase memory in spectroscopy of test field of two level system at small frequencies of collisions

    International Nuclear Information System (INIS)

    Parkhomenko, A.I.; Shalagin, A.M.

    2006-01-01

    One studied theoretically spectrum of absorption (intensification) of a weak sounding field by two-level atoms moving in a strong resonance laser field and colliding with buffer gas atoms. The analysis was performed for the case of small frequencies of collisions in contrast to the Doppler width of absorption line (gas low pressure) with regard to the arbitrary variation of a radiation induced dipole moment phase at elastic collisions of gas particles. The effects of phase memory are found to result in very strong quantitative and qualitative transformation of a test field spectrum even in case of infrequent collisions when the well-known Dike mechanism of manifestation of phase memory effects (elimination of the Doppler widening due to limitation of spatial motion of particles by collisions) does not work. Strong influence of phase memory effects on spectral resonances at gas low pressure results from the fact that phase retaining collisions change dependence on velocity of the partial index of refraction n(v) (index of refraction for particles moving with v velocity) [ru

  6. Quantum physics. The bottom-up approach. From the simple two-level system to irreducible representations

    International Nuclear Information System (INIS)

    Dubbers, Dirk; Stoeckmann, Hans-Juergen

    2013-01-01

    Helps in a compact form to reach good understanding of quantum physics. Shows important analogies between problems across different disciplines. Concise and accurate, written in a readable and lively style. Concentrates on the simplest quantum system which still displays the basic features of quantum theory. Chapters end with a general outlook on multi-level systems. Results are applied to a multitude of topics in modern science, from particle physics and quantum optics to time standards and magnetic resonance imaging. This concise tutorial provides the bachelor student and the practitioner with a short text on quantum physics that allows them to understand a wealth of quantum phenomena based on a compact, well readable, yet still concise and accurate description of nonrelativistic quantum theory. This ''quadrature of the circle'' is achieved by concentrating first on the simplest quantum system that still displays all basic features of quantum theory, namely, a system with only two quantized energy levels. For most readers it is very helpful to understand such simple systems before slowly proceeding to more demanding topics like particle entanglement, quantum chaos, or the use of irreducible tensors. This tutorial does not intend to replace the standard textbooks on quantum mechanics, but will help the average student to understand them, often for the first time.

  7. Quantum physics the bottom-up approach : from the simple two-level system to irreducible representations

    CERN Document Server

    Dubbers, Dirk

    2013-01-01

    This concise tutorial provides the bachelor student and the practitioner with a short text on quantum physics that allows them to understand a wealth of quantum phenomena based on a compact, well readable, yet still concise and accurate description of nonrelativistic quantum theory. This “quadrature of the circle” is achieved by concentrating first on the simplest quantum system that still displays all basic features of quantum theory, namely, a system with only two quantized energy levels. For most readers it is very helpful to understand such simple systems before slowly proceeding to more demanding topics like particle entanglement, quantum chaos, or the use of irreducible tensors. This tutorial does not intend to replace the standard textbooks on quantum mechanics, but will help the average student to understand them, often for the first time.

  8. Problem of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks

    International Nuclear Information System (INIS)

    Shorikov, A. F.

    2015-01-01

    This article discusses a discrete-time dynamical system consisting of a set a controllable objects (region and forming it municipalities). The dynamics each of these is described by the corresponding vector nonlinear discrete-time recurrent vector equations and its control system consist from two levels: basic (control level I) that is dominating and subordinate level (control level II). Both levels have different criterions of functioning and united a priori by determined informational and control connections defined in advance. In this paper we study the problem of optimization of guaranteed result for program control by the final state of regional social and economic system in the presence of risks. For this problem we proposed in this work an economical and mathematical model of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks and the general scheme for its solving

  9. Problem of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks

    Energy Technology Data Exchange (ETDEWEB)

    Shorikov, A. F., E-mail: afshorikov@mail.ru [Ural Federal University, 19 S. Mira, Ekaterinburg, 620002, Russia Institute of Mathematics and Mechanics, Ural Branch of Russian Academy of Sciences, 16 S. Kovalevskaya, Ekaterinburg, 620990 (Russian Federation)

    2015-11-30

    This article discusses a discrete-time dynamical system consisting of a set a controllable objects (region and forming it municipalities). The dynamics each of these is described by the corresponding vector nonlinear discrete-time recurrent vector equations and its control system consist from two levels: basic (control level I) that is dominating and subordinate level (control level II). Both levels have different criterions of functioning and united a priori by determined informational and control connections defined in advance. In this paper we study the problem of optimization of guaranteed result for program control by the final state of regional social and economic system in the presence of risks. For this problem we proposed in this work an economical and mathematical model of two-level hierarchical minimax program control the final state of regional social and economic system in the presence of risks and the general scheme for its solving.

  10. No-go theorem for one-way quantum computing on naturally occurring two-level systems

    International Nuclear Information System (INIS)

    Chen Jianxin; Chen Xie; Duan Runyao; Ji Zhengfeng; Zeng Bei

    2011-01-01

    The ground states of some many-body quantum systems can serve as resource states for the one-way quantum computing model, achieving the full power of quantum computation. Such resource states are found, for example, in spin-(5/2) and spin-(3/2) systems. It is, of course, desirable to have a natural resource state in a spin-(1/2), that is, qubit system. Here, we give a negative answer to this question for frustration-free systems with two-body interactions. In fact, it is shown to be impossible for any genuinely entangled qubit state to be a nondegenerate ground state of any two-body frustration-free Hamiltonian. What is more, we also prove that every spin-(1/2) frustration-free Hamiltonian with two-body interaction always has a ground state that is a product of single- or two-qubit states. In other words, there cannot be any interesting entanglement features in the ground state of such a qubit Hamiltonian.

  11. Integration of supercapacitive storage in renewable energy system to compare the response of two level and five level inverter with RL type load

    Science.gov (United States)

    Jana, Suman; Biswas, Pabitra Kumar; Das, Upama

    2018-04-01

    The analytical and simulation-based study in this presented paper shows a comparative report between two level inverter and five-level inverter with the integration of Supercapacitive storage in Renewable Energy system. Sometime dependent numerical models are used to measure the voltage and current response of two level and five level inverter in MATLAB Simulink based environment. In this study supercapacitive sources, which are fed by solar cells are used as input sources to experiment the response of multilevel inverter with integration of su-percapacitor as a storage device of Renewable Energy System. The RL load is used to compute the time response in MATLABSimulink based environment. With the simulation results a comparative study has been made of two different level types of inverters. Two basic types of inverter are discussed in the study with reference to their electrical behavior. It is also simulated that multilevel inverter can convert stored energy within supercapacitor which is extracted from Renewable Energy System.

  12. Generation and amplification of a high-order sideband induced by two-level atoms in a hybrid optomechanical system

    Science.gov (United States)

    Liu, Zeng-Xing; Xiong, Hao; Wu, Ying

    2018-01-01

    It is quite important to enhance and control the optomechanically induced high-order sideband generation to achieve low-power optical comb and high-sensitivity sensing with an integrable structure. Here we present and analyze a proposal for enhancement and manipulation of optical nonlinearity and high-order sideband generation in a hybrid atom-cavity optomechanical system that is coherently driven by a bichromatic input field consisting of a control field and a probe field and that works beyond the perturbative regime. Our numerical analysis with experimentally achievable parameters confirms that robust high-order sideband generation and typical spectral structures with nonperturbative features can be created even under weak driven fields. The dependence of the high-order sideband generation on the atomic parameters are also discussed in detail, including the decay rate of the atoms and the coupling parameter between the atoms and the cavity field. We show that the cutoff order as well as the amplitude of the higher-order sidebands can be well tuned by the atomic coupling strength and the atomic decay rate. The proposed mechanism of enhancing optical nonlinearity is quite general and can be adopted to optomechanical systems with different types of cavity.

  13. Bridging the Gap Between the Social and the Technical: The Enrolment of Socio-Technical Information Architects to Cope with the Two-Level Model of EPR Systems.

    Science.gov (United States)

    Pedersen, Rune

    2017-01-01

    This is a project proposal derived from an urge to re-define the governance of ICT in healthcare towards regional and national standardization of the patient pathways. The focus is on a two-levelled approach for governing EPR systems where the clinicians' model structured variables and patient pathways. The overall goal is a patient centric EPR portfolio. This paper define and enlighten the need for establishing the socio- technical architect role necessary to obtain the capabilities of a modern structured EPR system. Clinicians are not capable to moderate between the technical and the clinical.

  14. Relaxation dynamics of a driven two-level system coupled to a Bose-Einstein condensate: application to quantum dot-dipolar exciton gas hybrid systems.

    Science.gov (United States)

    Kovalev, Vadim M; Tse, Wang-Kong

    2017-11-22

    We develop a microscopic theory for the relaxation dynamics of an optically pumped two-level system (TLS) coupled to a bath of weakly interacting Bose gas. Using Keldysh formalism and diagrammatic perturbation theory, expressions for the relaxation times of the TLS Rabi oscillations are derived when the boson bath is in the normal state and the Bose-Einstein condensate (BEC) state. We apply our general theory to consider an irradiated quantum dot coupled with a boson bath consisting of a two-dimensional dipolar exciton gas. When the bath is in the BEC regime, relaxation of the Rabi oscillations is due to both condensate and non-condensate fractions of the bath bosons for weak TLS-light coupling and pre dominantly due to the non-condensate fraction for strong TLS-light coupling. Our theory also shows that a phase transition of the bath from the normal to the BEC state strongly influences the relaxation rate of the TLS Rabi oscillations. The TLS relaxation rate is approximately independent of the pump field frequency and monotonically dependent on the field strength when the bath is in the low-temperature regime of the normal phase. Phase transition of the dipolar exciton gas leads to a non-monotonic dependence of the TLS relaxation rate on both the pump field frequency and field strength, providing a characteristic signature for the detection of BEC phase transition of the coupled dipolar exciton gas.

  15. New Aspects of Field Entropy Squeezing as an Indicator for Mixed State Entanglement in an Effective Two-Level System with Stark Shift

    Institute of Scientific and Technical Information of China (English)

    S.Abdel-Khalek; M.M.A.Ahmed; A-S F.Obada

    2011-01-01

    We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic field,initially prepared in a coherent state.Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested.The temporal evolution of the negativity,Wehrl entropy,Wehrl phase distribution and field entropy squeezing are investigated.The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy,Wehrl phase distribution and field entropy squeezing.%We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic Reid, initially prepared in a coherent state. Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested. The temporal evolution of the negativity, Wehrl entropy, Wehrl phase distribution and field entropy squeezing are investigated. The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy, Wehrl phase distribution and field entropy squeezing.

  16. Power and polarization dependences of ultra-narrow electromagnetically induced absorption (EIA) spectra of 85 Rb atoms in degenerate two-level system

    Science.gov (United States)

    Qureshi, Muhammad Mohsin; Rehman, Hafeez Ur; Noh, Heung-Ryoul; Kim, Jin-Tae

    2016-05-01

    We have investigated ultra-narrow EIA spectral features with respect to variations of polarizations and powers of pump laser beam in a degenerate two-level system of the transition of 85 Rb D2 transition line. Polarizations of the probe laser beam in two separate experiments were fixed at right circular and horizontal linear polarizations, respectively while the polarizations of the pump lasers were varied from initial polarizations same as the probe laser beams to orthogonal to probe polarizations. One homemade laser combined with AOMs was used to the pump and probe laser beams instead of two different lasers to overcome broad linewidths of the homemade lasers. Theoretically, probe absorption coefficients have been calculated from optical Bloch equations of the degenerate two level system prepared by a pump laser beam. In the case of the circular polarization, EIA signal was obtained as expected theoretically although both pump and probe beams have same polarization. The EIA signal become smaller as power increases and polarizations of the pump and probe beams were same. When the polarization of the pump beam was linear polarization, maximum EIA signal was obtained theoretically and experimentally. Experimental EIA spectral shapes with respect to variations of the pump beam polarization shows similar trends as the theoretical results.

  17. Optimal Design of Integrated Systems Health Management (ISHM) Systems for improving safety in NASA's Exploration Vehicles: A Two-Level Multidisciplinary Design Approach

    Science.gov (United States)

    Mehr, Ali Farhang; Tumer, Irem; Barszcz, Eric

    2005-01-01

    Integrated Vehicle Health Management (ISHM) systems are used to detect, assess, and isolate functional failures in order to improve safety of space systems such as Orbital Space Planes (OSPs). An ISHM system, as a whole, consists of several subsystems that monitor different components of an OSP including: Spacecraft, Launch Vehicle, Ground Control, and the International Space Station. In this research, therefore, we propose a new methodology to design and optimize ISHM as a distributed system with multiple disciplines (that correspond to different subsystems of OSP safety). A paramount amount of interest has been given in the literature to the multidisciplinary design optimization of problems with such architecture (as will be reviewed in the full paper).

  18. Modeling the dynamics of multipartite quantum systems created departing from two-level systems using general local and non-local interactions

    Science.gov (United States)

    Delgado, Francisco

    2017-12-01

    Quantum information is an emergent area merging physics, mathematics, computer science and engineering. To reach its technological goals, it is requiring adequate approaches to understand how to combine physical restrictions, computational approaches and technological requirements to get functional universal quantum information processing. This work presents the modeling and the analysis of certain general type of Hamiltonian representing several physical systems used in quantum information and establishing a dynamics reduction in a natural grammar for bipartite processing based on entangled states.

  19. Reliability of structural systems subject to fatigue

    International Nuclear Information System (INIS)

    Rackwitz, R.

    1984-01-01

    Concepts and computational procedures for the reliability calculation of structural systems subject to fatigue are outlined. Systems are dealt with by approximately computing componential times to first failure. So-called first-order reliability methods are then used to formulate dependencies between componential failures and to evaluate the system failure probability. (Author) [pt

  20. Reduction of Subjective and Objective System Complexity

    Science.gov (United States)

    Watson, Michael D.

    2015-01-01

    Occam's razor is often used in science to define the minimum criteria to establish a physical or philosophical idea or relationship. Albert Einstein is attributed the saying "everything should be made as simple as possible, but not simpler". These heuristic ideas are based on a belief that there is a minimum state or set of states for a given system or phenomena. In looking at system complexity, these heuristics point us to an idea that complexity can be reduced to a minimum. How then, do we approach a reduction in complexity? Complexity has been described as a subjective concept and an objective measure of a system. Subjective complexity is based on human cognitive comprehension of the functions and inter relationships of a system. Subjective complexity is defined by the ability to fully comprehend the system. Simplifying complexity, in a subjective sense, is thus gaining a deeper understanding of the system. As Apple's Jonathon Ive has stated," It's not just minimalism or the absence of clutter. It involves digging through the depth of complexity. To be truly simple, you have to go really deep". Simplicity is not the absence of complexity but a deeper understanding of complexity. Subjective complexity, based on this human comprehension, cannot then be discerned from the sociological concept of ignorance. The inability to comprehend a system can be either a lack of knowledge, an inability to understand the intricacies of a system, or both. Reduction in this sense is based purely on a cognitive ability to understand the system and no system then may be truly complex. From this view, education and experience seem to be the keys to reduction or eliminating complexity. Objective complexity, is the measure of the systems functions and interrelationships which exist independent of human comprehension. Jonathon Ive's statement does not say that complexity is removed, only that the complexity is understood. From this standpoint, reduction of complexity can be approached

  1. Extended Cognitive System and Epistemic Subject

    Directory of Open Access Journals (Sweden)

    Trybulec Barbara

    2015-03-01

    Full Text Available The concept of an extended cognitive system is central to contemporary studies of cognition. In the paper I analyze the place of the epistemic subject within the extended cognitive system. Is it extended as well? In answering this question I focus on the differences between the first and the second wave of arguments for the extended mind thesis. I argue that the position of Cognitive Integration represented by Richard Menary is much more intuitive and fruitful in analyses of cognition and knowledge than the early argument formulated by Andy Clark and David Chalmers. Cognitive Integration is compatible with virtue epistemology of John Greco’s agent reliabilism. The epistemic subject is constituted by its cognitive character composed of an integrated set of cognitive abilities and processes. Some of these processes are extended, they are a manipulation of external informational structures and, as such, they constitute epistemic practices. Epistemic practices are normative; to conduct them correctly the epistemic subject needs to obey epistemic norms embedded in the cultural context. The epistemic subject is not extended because of the casual coupling with external informational artifacts which extend his mind from inside the head and into the world. Rather, cognitive practices constitute the subject’s mind, they transform his cognitive abilities, and this is what makes the mind and epistemic subject “extended”.

  2. The Subject Analysis of Payment Systems Characteristics

    Directory of Open Access Journals (Sweden)

    Korobeynikova Olga Mikhaylovna

    2015-09-01

    Full Text Available The article deals with the analysis of payment systems aimed at identifying the categorical terminological apparatus, proving their specific features and revealing the impact of payment systems on the state of money turnover. On the basis of the subject analysis, the author formulates the definitions of a payment system (characterized by increasing speed of effecting payments, by the reduction of costs, by high degree of payments convenience for subjects of transactions, by security of payments, by acceptable level of risks and by social efficiency, a national payment system, and a local payment system (characterized by the growth of economic and social efficiency of systems participants, by the process of money turnover optimization on the basis of saving transaction costs and increasing speed of money flows within the local payment systems. According to the economic levels, the payment systems are divided to macrosystems (national payment systems, mezosystems (payment systems localized on the operational and territorial basis, microsystems (payments by individual economic subjects. The establishment of qualitative features of payment systems, which is a basis of the author’s terminological interpretation, gave a possibility to reveal the cause-effect relations of payment systems influence on the state of money turnover in the involved subjects, and on the economy as a whole. The result of the present research consists in revealing the payment systems influence on the state of money turnover which is significant: at the state and regional level – in the optimization of budget and inter-budgetary relations, in acceleration of the money turnover, in deceleration of the money supply and inflation rate, in reduced need in money emission; at the level of economic entities – in accelerating the money turnover and accounts receivable, in the reduction of debit and credit loans, in the growth of profit (turnover; at the household level – in

  3. A Hybrid System for Subjectivity Analysis

    Directory of Open Access Journals (Sweden)

    Samir Rustamov

    2018-01-01

    Full Text Available We suggested different structured hybrid systems for the sentence-level subjectivity analysis based on three supervised machine learning algorithms, namely, Hidden Markov Model, Fuzzy Control System, and Adaptive Neuro-Fuzzy Inference System. The suggested feature extraction algorithm in our experiment computes a feature vector using statistical textual terms frequencies in a training dataset not having the use of any lexical knowledge except tokenization. Taking into consideration this fact, the above-mentioned methods may be employed in other languages as these methods do not utilize the morphological, syntactical, and lexical analysis in the classification problems.

  4. A two-level voltage source inverter with differentially sinusoidal pulse width modulation used in the interconnection system of a wind turbine generator

    Directory of Open Access Journals (Sweden)

    Alexandros C. Charalampidis

    2014-10-01

    Full Text Available This study analyses an interconnection system based on differentially sinusoidal pulse width modulation, used for the interconnection to the grid of a variable speed wind turbine. The modulation technique used provides specific advantages in comparison with the commonly used sinusoidal pulse width modulation (SPWM technique, such as lower DC bus voltage requirements, smaller switching losses for the same switching frequency as well as less higher harmonic content in the voltage waveforms produced. The respective control system is also described in detail. Thus this study provides a guide enabling the design of any interconnection system based on this modulation technique.

  5. Development of an integrated model for energy systems planning and carbon dioxide mitigation under uncertainty - Tradeoffs between two-level decision makers.

    Science.gov (United States)

    Jin, S W; Li, Y P; Xu, L P

    2018-07-01

    A bi-level fuzzy programming (BFLP) method was developed for energy systems planning (ESP) and carbon dioxide (CO 2 ) mitigation under uncertainty. BFLP could handle fuzzy information and leader-follower problem in decision-making processes. It could also address the tradeoffs among different decision makers in two decision-making levels through prioritizing the most important goal. Then, a BFLP-ESP model was formulated for planning energy system of Beijing, in which the upper-level objective is to minimize CO 2 emission and the lower-level objective is to minimize the system cost. Results provided a range of decision alternatives that corresponded to a tradeoff between system optimality and reliability under uncertainty. Compared to the single-level model with a target to minimize system cost, the amounts of pollutant/CO 2 emissions from BFLP-ESP were reduced since the study system would prefer more clean energies (i.e. natural gas, LPG and electricity) to replace coal fuel. Decision alternatives from BFLP were more beneficial for supporting Beijing to adjust its energy mix and enact its emission-abatement policy. Results also revealed that the low-carbon policy for power plants (e.g., shutting down all coal-fired power plants) could lead to a potentially increment of imported energy for Beijing, which would increase the risk of energy shortage. The findings could help decision makers analyze the interactions between different stakeholders in ESP and provide useful information for policy design under uncertainty. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. The Two-Level Theory of verb meaning: An approach to integrating the semantics of action with the mirror neuron system.

    Science.gov (United States)

    Kemmerer, David; Gonzalez-Castillo, Javier

    2010-01-01

    Verbs have two separate levels of meaning. One level reflects the uniqueness of every verb and is called the "root". The other level consists of a more austere representation that is shared by all the verbs in a given class and is called the "event structure template". We explore the following hypotheses about how, with specific reference to the motor features of action verbs, these two distinct levels of semantic representation might correspond to two distinct levels of the mirror neuron system. Hypothesis 1: Root-level motor features of verb meaning are partially subserved by somatotopically mapped mirror neurons in the left primary motor and/or premotor cortices. Hypothesis 2: Template-level motor features of verb meaning are partially subserved by representationally more schematic mirror neurons in Brodmann area 44 of the left inferior frontal gyrus. Evidence has been accumulating in support of the general neuroanatomical claims made by these two hypotheses-namely, that each level of verb meaning is associated with the designated cortical areas. However, as yet no studies have satisfied all the criteria necessary to support the more specific neurobiological claims made by the two hypotheses-namely, that each level of verb meaning is associated with mirror neurons in the pertinent brain regions. This would require demonstrating that within those regions the same neuronal populations are engaged during (a) the linguistic processing of particular motor features of verb meaning, (b) the execution of actions with the corresponding motor features, and (c) the observation of actions with the corresponding motor features. 2008 Elsevier Inc. All rights reserved.

  7. Researching Subjective Meaning System of Music Consumers

    Directory of Open Access Journals (Sweden)

    Mohammad Taghi Iman

    2011-06-01

    Full Text Available The purpose of this qualitative study is to explain the subjective meaning system of consumers of the popular music. Participants in this study include 21 students (male and female living in dormitories of Shiraz University. Researches use qualitative approach of grounded theory. Technique of data collection has been in-depth interviews. Data have been analyzed with qualitative software called NVIVO. Analyze the data and paradigmatic model shows that the grounded condition for participants, including “spatial texture” of accommodation based on a subset of locality plus time coordination, participant’s age necessitation, collective identity. Meanwhile, global market trends and fashionism influence as interfering conditions. Participants placed in these conditions, take developed and alternative musical factor and increased mental absenteeism quotient. As a result of taking this strategy, the consequences of idio-sensuation (image of the other [alter image]self-reincarnation and psychology projection will be introduced. Idio-sensuation naturally implies that the participant initiate music consumption in such a manner as to bring in their own personal mental images as contrasted with other’s which in itself possess multifarious dimensions having been in a state of fluctuation in between two diverse pole of psychological projection and self-reincarnation.

  8. Evolution of the field quantum entropy and entanglement in a system of multimode light field interacting resonantly with a two-level atom through N_j-degenerate N~Σ-photon process

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.

  9. Identification systems subject to plan cybersecurity

    International Nuclear Information System (INIS)

    Guerrero Sanz, J.; Perez Alcaniz, T.; Garcia Garcia, I.

    2012-01-01

    The implementation of a Plan Cybersecurity ensures that systems and communications networks that perform functions related to both physical security such emergency action and their support systems, and interfaces that may affect them, are protected with an effective system against cyber attacks.

  10. Subjectivity

    Directory of Open Access Journals (Sweden)

    Jesús Vega Encabo

    2015-11-01

    Full Text Available In this paper, I claim that subjectivity is a way of being that is constituted through a set of practices in which the self is subject to the dangers of fictionalizing and plotting her life and self-image. I examine some ways of becoming subject through narratives and through theatrical performance before others. Through these practices, a real and active subjectivity is revealed, capable of self-knowledge and self-transformation. 

  11. Two-Level Semantics and Code Generation

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nielson, Hanne Riis

    1988-01-01

    A two-level denotational metalanguage that is suitable for defining the semantics of Pascal-like languages is presented. The two levels allow for an explicit distinction between computations taking place at compile-time and computations taking place at run-time. While this distinction is perhaps...... not absolutely necessary for describing the input-output semantics of programming languages, it is necessary when issues such as data flow analysis and code generation are considered. For an example stack-machine, the authors show how to generate code for the run-time computations and still perform the compile...

  12. System reliability analysis with natural language and expert's subjectivity

    International Nuclear Information System (INIS)

    Onisawa, T.

    1996-01-01

    This paper introduces natural language expressions and expert's subjectivity to system reliability analysis. To this end, this paper defines a subjective measure of reliability and presents the method of the system reliability analysis using the measure. The subjective measure of reliability corresponds to natural language expressions of reliability estimation, which is represented by a fuzzy set defined on [0,1]. The presented method deals with the dependence among subsystems and employs parametrized operations of subjective measures of reliability which can reflect expert 's subjectivity towards the analyzed system. The analysis results are also expressed by linguistic terms. Finally this paper gives an example of the system reliability analysis by the presented method

  13. Maximising water supply system yield subject to multiple reliability ...

    African Journals Online (AJOL)

    Maximising water supply system yield subject to multiple reliability constraints via simulation-optimisation. ... Water supply systems have to satisfy different demands that each require various levels of reliability ... and monthly operating rules that maximise the yield of a water supply system subject to ... HOW TO USE AJOL.

  14. The User-Subjective Approach to Personal Information Management Systems.

    Science.gov (United States)

    Bergman, Ofer; Beyth-Marom, Ruth; Nachmias, Rafi

    2003-01-01

    Explains personal information management (PIM) systems and suggests a user-subjective approach to PIM system design. Advocates that PIM systems relate to the subjective value-added attributes that the user gives the stored data so that the user can find information again, recall it when needed, and use it effectively in the next interaction.…

  15. Two-level convolution formula for nuclear structure function

    Science.gov (United States)

    Ma, Boqiang

    1990-05-01

    A two-level convolution formula for the nuclear structure function is derived in considering the nucleus as a composite system of baryon-mesons which are also composite systems of quark-gluons again. The results show that the European Muon Colaboration effect can not be explained by the nuclear effects as nucleon Fermi motion and nuclear binding contributions.

  16. Two-level convolution formula for nuclear structure function

    International Nuclear Information System (INIS)

    Ma Boqiang

    1990-01-01

    A two-level convolution formula for the nuclear structure function is derived in considering the nucleus as a composite system of baryon-mesons which are also composite systems of quark-gluons again. The results show that the European Muon Colaboration effect can not be explained by the nuclear effects as nucleon Fermi motion and nuclear binding contributions

  17. An Expert System Approach to Online Catalog Subject Searching.

    Science.gov (United States)

    Khoo, Christopher S. G.; Poo, Danny C. C.

    1994-01-01

    Reviews methods to improve online catalogs for subject searching and describes the design of an expert system front-end to improve subject access in online public access catalogs that focuses on search strategies. Implementation of a prototype system at the National University of Singapore is described, and reformulation strategies are discussed.…

  18. System and method for acquisition management of subject position information

    Science.gov (United States)

    Carrender, Curt

    2005-12-13

    A system and method for acquisition management of subject position information that utilizes radio frequency identification (RF ID) to store position information in position tags. Tag programmers receive position information from external positioning systems, such as the Global Positioning System (GPS), from manual inputs, such as keypads, or other tag programmers. The tag programmers program each position tag with the received position information. Both the tag programmers and the position tags can be portable or fixed. Implementations include portable tag programmers and fixed position tags for subject position guidance, and portable tag programmers for collection sample labeling. Other implementations include fixed tag programmers and portable position tags for subject route recordation. Position tags can contain other associated information such as destination address of an affixed subject for subject routing.

  19. System and method for acquisition management of subject position information

    Energy Technology Data Exchange (ETDEWEB)

    Carrender, Curt [Morgan Hill, CA

    2007-01-23

    A system and method for acquisition management of subject position information that utilizes radio frequency identification (RF ID) to store position information in position tags. Tag programmers receive position information from external positioning systems, such as the Global Positioning System (GPS), from manual inputs, such as keypads, or other tag programmers. The tag programmers program each position tag with the received position information. Both the tag programmers and the position tags can be portable or fixed. Implementations include portable tag programmers and fixed position tags for subject position guidance, and portable tag programmers for collection sample labeling. Other implementations include fixed tag programmers and portable position tags for subject route recordation. Position tags can contain other associated information such as destination address of an affixed subject for subject routing.

  20. Digitized video subject positioning and surveillance system for PET

    International Nuclear Information System (INIS)

    Picard, Y.; Thompson, C.J.

    1995-01-01

    Head motion is a significant contribution to the degradation of image quality of Positron Emission Tomography (PET) studies. Images from different studies must also be realigned digitally to be correlated when the subject position has changed. These constraints could be eliminated if the subject's head position could be monitored accurately. The authors have developed a video camera-based surveillance system to monitor the head position and motion of subjects undergoing PET studies. The system consists of two CCD (charge-coupled device) cameras placed orthogonally such that both face and profile views of the subject's head are displayed side by side on an RGB video monitor. Digitized images overlay the live images in contrasting colors on the monitor. Such a system can be used to (1) position the subject in the field of view (FOV) by displaying the position of the scanner's slices on the monitor along with the current subject position, (2) monitor head motion and alert the operator of any motion during the study and (3) reposition the subject accurately for subsequent studies by displaying the previous position along with the current position in a contrasting color

  1. Optical resonance and two-level atoms

    CERN Document Server

    Allen, L

    1987-01-01

    ""Coherent and lucid…a valuable summary of a subject to which [the authors] have made significant contributions by their own research."" - Contemporary PhysicsOffering an admirably clear account of the basic principles behind all quantum optical resonance phenomena, and hailed as a valuable contribution to the literature of nonlinear optics, this distinguished work provides graduate students and research physicists probing fields such as laser physics, quantum optics, nonlinear optics, quantum electronics, and resonance optics an ideal introduction to the study of the interaction of electroma

  2. Memory Effects in the Two-Level Model for Glasses

    Science.gov (United States)

    Aquino, Gerardo; Allahverdyan, Armen; Nieuwenhuizen, Theo M.

    2008-07-01

    We study an ensemble of two-level systems interacting with a thermal bath. This is a well-known model for glasses. The origin of memory effects in this model is a quasistationary but nonequilibrium state of a single two-level system, which is realized due to a finite-rate cooling and slow thermally activated relaxation. We show that single-particle memory effects, such as negativity of the specific heat under reheating, vanish for a sufficiently disordered ensemble. In contrast, a disordered ensemble displays a collective memory effect [similar to the Kovacs effect], where nonequilibrium features of the ensemble are monitored via a macroscopic observable. An experimental realization of the effect can be used to further assess the consistency of the model.

  3. Hydraulic braking system for loads subjected to impacts and vibrations

    International Nuclear Information System (INIS)

    1980-01-01

    This invention concerns a hydraulic braking system for loads subjected to impacts and vibrations. These double acting telescopic type hydraulic braking systems possess significant drawbacks linked to possibly important hydraulic leaks due to (a) the use of many dynamic seals in such appliances and (b) the effects of the environment of the system on these seals, particularly when employed in nuclear power stations where the seals reach significant temperatures and are subjected to radiation. Under this invention a remedy is suggested to such drawbacks by integrating means to offset automatically the leaks and the accumulation of hydraulic fluid expansions, as well as facilities to show if such leaks have occurred [fr

  4. Study on the subject system of environmental radiochemistry

    International Nuclear Information System (INIS)

    Qiang Yi zhong

    1992-11-01

    The environmental radiochemistry is a new frontier discipline. So, it is very important to study the system of this subject. A brief introduction of its development background and history are presented. The definition of the environmental radiochemistry has been studied. Main contents containing in the subject have been classified and reviewed in accordance with different modalities. Five major features of the environmental radiochemistry are suggested. Issues to be considered recently in the environmental radiochemistry are also discussed

  5. Seismic analysis of piping systems subjected to multiple support excitations

    International Nuclear Information System (INIS)

    Sundararajan, C.; Vaish, A.K.; Slagis, G.C.

    1981-01-01

    The paper presents the results of a comparative study between the multiple response spectrum method and the time-history method for the seismic analysis of nuclear piping systems subjected to different excitation at different supports or support groups. First, the necessary equations for the above analysis procedures are derived. Then, three actual nuclear piping systems subjected to single and multiple excitations are analyzed by the different methods, and extensive comparisons of the results (stresses) are made. Based on the results, it is concluded that the multiple response spectrum analysis gives acceptable results as compared to the ''exact'', but much more costly, time-history analysis. 6 refs

  6. Information Science and Information Systems: Conjunct Subjects Disjunct Disciplines.

    Science.gov (United States)

    Ellis, David; Allen, David; Wilson, Tom

    1999-01-01

    Examines the relationship between information science and information-systems (IS) research through analysis of the subject literature of each field and by citation and co-citation analysis of highly cited researchers in each field. Subfields of user studies and information-retrieval research were selected to represent information-science…

  7. Subjective visual vertical assessment with mobile virtual reality system

    Directory of Open Access Journals (Sweden)

    Ingrida Ulozienė

    Full Text Available Background and objective: The subjective visual vertical (SVV is a measure of a subject's perceived verticality, and a sensitive test of vestibular dysfunction. Despite this, and consequent upon technical and logistical limitations, SVV has not entered mainstream clinical practice. The aim of the study was to develop a mobile virtual reality based system for SVV test, evaluate the suitability of different controllers and assess the system's usability in practical settings. Materials and methods: In this study, we describe a novel virtual reality based system that has been developed to test SVV using integrated software and hardware, and report normative values across healthy population. Participants wore a mobile virtual reality headset in order to observe a 3D stimulus presented across separate conditions – static, dynamic and an immersive real-world (“boat in the sea” SVV tests. The virtual reality environment was controlled by the tester using a Bluetooth connected controllers. Participants controlled the movement of a vertical arrow using either a gesture control armband or a general-purpose gamepad, to indicate perceived verticality. We wanted to compare 2 different methods for object control in the system, determine normal values and compare them with literature data, to evaluate the developed system with the help of the system usability scale questionnaire and evaluate possible virtually induced dizziness with the help of subjective visual analog scale. Results: There were no statistically significant differences in SVV values during static, dynamic and virtual reality stimulus conditions, obtained using the two different controllers and the results are compared to those previously reported in the literature using alternative methodologies. The SUS scores for the system were high, with a median of 82.5 for the Myo controller and of 95.0 for the Gamepad controller, representing a statistically significant difference between the two

  8. Maintenance scheduling of a manufacturing system subject to deterioration

    International Nuclear Information System (INIS)

    Ahmadi, Reza; Newby, Martin

    2011-01-01

    This paper presents an integrated model for the joint determination of both optimal inspection strategy and optimal repair policy for a manufacturing system whose resulting output is subject to system state. An appropriate maintenance strategy is essential to optimize revenue from a manufacturing system which is in continuous operation and subject to deterioration. The optimum policy balances the amount of maintenance required to increase availability against the loss of revenue arising from the down time: insufficient maintenance leads to an increase in the number of defective items, low profit and low maintenance cost; excessive maintenance results in a reduction in the proportion of defective items, high profit and high maintenance cost. In this paper, an intensity control model adapted to partial information provides an optimal inspection intensity and repair degree of the system as an optimal control process to yield maximum revenue. The solution is obtained through formulating an equivalent deterministic Hamilton-Jacobi equation. A numerical example is provided to illustrate the behavior of the optimal control process. The optimal control process determines a solution to both optimum inspection frequency and optimal replacement policy which results in an optimal production run length of the system. - Highlights: → We develop an optimum asset management strategy based on the revenue generated by the asset. → The optimum strategy controls the intensity, rate of occurrence, of interruptions to service. → The decisions are based on partial observation of the system and do not need perfect information. There is no need for continuous monitoring of the system.

  9. SYSTEM EDUCATION CONCEPTS OF THE SUBJECT AND ITS GRAPHIC REPRESENTATION

    Directory of Open Access Journals (Sweden)

    Артём Авенирович Михайлюк

    2017-12-01

    Full Text Available The article draws attention to the fact that the teacher in the course of constructing the course of the subject there is a need for systematization and structuring of the system of concepts of the academic subject, which is the basis of the future course. The choice of the system of concepts and ways to represent it depends on the period of the course and the cognitive abilities of the students. The presentation of a system of concepts in the form of infographics can help a teacher to develop a training course faster and more efficiently, and to teach it to his students. Beautiful clear graphs and diagrams are better perceived and remembered. And modern information technology allows you to create and share knowledge and research results in a spectacular, long- remembered form. And we must match time, and moreover, teach children to work with information in such a way that it would be desirable to look at it. In the process of such training, the teacher and students are formed interest in the subject, developing visual thinking.

  10. Two-level modelling of real estate taxtation

    DEFF Research Database (Denmark)

    Gall, Jaroslav; Stubkjær, Erik

    2006-01-01

    Real estate taxes recurrently attract attention, because they are a source of potentially increased revenue for local and national government. Most experts agree that it is necessary to switch from using normative values for taxation to a market-value-based taxation of real property with computer......-assisted mass valuation, witch benefit from use of value maps. In Czech Republic, efforts have been made to adopt current tax policy goals, but improvements are still needed. The paper aims at supporting the current improvement process towards a market based system. It presents models, which describe aspects...... of the present Czech property tax system. A proposal for the future system focuses on the value map component. The described change depends on political involvement. This political activity is modelled as well. The hypothesis is that the two-level modelling effort enhances the change process by providing...

  11. Dynamic response of piping system subject to flow acoustic excitation

    International Nuclear Information System (INIS)

    Wang, T.; Sun, Y.S.

    1988-01-01

    Through the use of a theoretically derived and test data-calibrated forcing function, the dynamic response of a piping system subject to flow-acoustic induced vibration is analyzed. It is shown that the piping behavior can be predicted when consideration is given to both the wall flexural vibration and the piping system vibration. Piping responded as a system to the transversal excitation due to the swirling motion of the fluid flow, as well as flexurally to the high-frequency acoustic excitations. The transverse piping system response was calculated using a lumped mass piping model. The piping model has more stringent requirements than its counterpart for waterhammer and seismic modeling due to the shorter spiral wavelength and higher frequency of the forcing function. Proper modeling ensured that both the moment stress caused by system excitation and the local stress induced by the support reaction load were properly accounted for. Flexural vibration not only poses a threat to nipples and branch connections, but also contributes substantially to the resultant total stress experienced by the pipe. The forcing function approach has the advantage that the critical locations on the piping system can be identified by means of analysis, facilitating surveillance and inspection, as well as fatigue evaluation

  12. Moderation analysis using a two-level regression model.

    Science.gov (United States)

    Yuan, Ke-Hai; Cheng, Ying; Maxwell, Scott

    2014-10-01

    Moderation analysis is widely used in social and behavioral research. The most commonly used model for moderation analysis is moderated multiple regression (MMR) in which the explanatory variables of the regression model include product terms, and the model is typically estimated by least squares (LS). This paper argues for a two-level regression model in which the regression coefficients of a criterion variable on predictors are further regressed on moderator variables. An algorithm for estimating the parameters of the two-level model by normal-distribution-based maximum likelihood (NML) is developed. Formulas for the standard errors (SEs) of the parameter estimates are provided and studied. Results indicate that, when heteroscedasticity exists, NML with the two-level model gives more efficient and more accurate parameter estimates than the LS analysis of the MMR model. When error variances are homoscedastic, NML with the two-level model leads to essentially the same results as LS with the MMR model. Most importantly, the two-level regression model permits estimating the percentage of variance of each regression coefficient that is due to moderator variables. When applied to data from General Social Surveys 1991, NML with the two-level model identified a significant moderation effect of race on the regression of job prestige on years of education while LS with the MMR model did not. An R package is also developed and documented to facilitate the application of the two-level model.

  13. Maintaining a system subject to uncertain technological evolution

    International Nuclear Information System (INIS)

    Nguyen, T.P.K.; Castanier, Bruno; Yeung, Thomas G.

    2014-01-01

    Maintenance decisions can be directly affected by the introduction of a new asset on the market, especially when the new asset technology could increase the expected profit. However new technology has a high degree of uncertainty that must be considered such as, e.g., its appearance time on the market, the expected revenue and the purchase cost. In this way, maintenance optimization can be seen as an investment problem where the repair decision is an option for postponing a replacement decision in order to wait for a potential new asset. Technology investment decisions are usually based primarily on strategic parameters such as current probability and expected future benefits while maintenance decisions are based on “functional” parameters such as deterioration levels of the current system and associated maintenance costs. In this paper, we formulate a new combined mathematical optimization framework for taking into account both maintenance and replacement decisions when the new asset is subject to technological improvement. The decision problem is modelled as a non-stationary Markov decision process. Structural properties of the optimal policy and forecast horizon length are then derived in order to guarantee decision optimality and robustness over the infinite horizon. Finally, the performance of our model is highlighted through numerical examples

  14. Heterogeneity and subjectivity in binary-state opinion formation systems

    International Nuclear Information System (INIS)

    Guo, Long; Luo, Zhongjie; Zhu, Yueying

    2013-01-01

    In society, there is heterogeneous interaction and randomness in human decision making. In order to unfold the roles and the competition of the two factors mentioned above in opinion formation, we propose a toy model, which follows a majority rule with a Fermi function, on scale-free networks with degree exponent γ. The heterogeneous interaction is related to the connectivity of a person with the interactive parameter β, and the randomness of human decision making is quantified by the interaction noise T. We find that a system with heterogeneity of network topology and interaction shows robustness perturbed by the interaction noise T according to the theoretical analysis and numerical simulation. Then, when T → 0, the homogeneous interaction (β ≃ 0) has a powerful implication for the emergence of a consensus state. Furthermore, the emergence of the two extreme values shows the competition of the heterogeneity of interaction and the subjectivity of human decision making in opinion formation. Our present work provides some perspective on and tools for understanding the diversity of opinion in our society. (paper)

  15. Two level undercut-profile substrate for filamentary YBa2Cu3O7 coated conductors

    DEFF Research Database (Denmark)

    Wulff, Anders Christian; Solovyov, M.; Gömöry, Fedor

    2015-01-01

    A novel substrate design is presented for scalable industrial production of filamentary coated conductors (CCs). The new substrate, called ‘two level undercut-profile substrate (2LUPS)’, has two levels of plateaus connected by walls with an undercut profile. The undercuts are made to produce...... a shading effect during subsequent deposition of layers, thereby creating gaps in the superconducting layer deposited on the curved walls between the two levels. It is demonstrated that such 2LUPS-based CCs can be produced in a large-scale production system using standard deposition processes...

  16. Electroretinography in healthy subjects in relation to systemic glucocorticoid intake

    DEFF Research Database (Denmark)

    Kappelgaard, Per; Hansen, Katrine B; Vilsbøll, Tina

    2012-01-01

    This study examined electroretinographic function in healthy subjects before and after prednisolone intake. To separate the effect of prednisolone on the retina from the potentially confounding hyperglycemia-inducing effect of prednisolone, electroretinography was made while fasting and at a pre-...

  17. Electroretinography in healthy subjects in relation to systemic glucocorticoid intake

    DEFF Research Database (Denmark)

    Kappelgaard, Per; Hansen, Katrine B; Vilsbøll, Tina

    2012-01-01

    .011) and post-prandial glycemia (P = 0.023). We conclude that prednisolone had no detectable effect on the ffERG in healthy lean men in this study. Retinal function may be less sensitive to changes in glycemia in healthy subjects than in people with diabetes, a characteristic that was unchanged by a short...

  18. Teaching innovation system applied in business management subjects.

    Directory of Open Access Journals (Sweden)

    Rafael Rosillo

    2017-06-01

    Blunder offers a fun mobile training. We can know which student learns faster, learns more or learns better a particular topic. If a student plays the subject that the teacher has explained in class the level of learning affects to the final evaluation positively.

  19. Evaluating system reliability and targeted hardening strategies of power distribution systems subjected to hurricanes

    International Nuclear Information System (INIS)

    Salman, Abdullahi M.; Li, Yue; Stewart, Mark G.

    2015-01-01

    Over the years, power distribution systems have been vulnerable to extensive damage from hurricanes which can cause power outage resulting in millions of dollars of economic losses and restoration costs. Most of the outage is as a result of failure of distribution support structures. Over the years, various methods of strengthening distribution systems have been proposed and studied. Some of these methods, such as undergrounding of the system, have been shown to be unjustified from an economic point of view. A potential cost-effective strategy is targeted hardening of the system. This, however, requires a method of determining critical parts of a system that when strengthened, will have greater impact on reliability. This paper presents a framework for studying the effectiveness of targeted hardening strategies on power distribution systems subjected to hurricanes. The framework includes a methodology for evaluating system reliability that relates failure of poles and power delivery, determination of critical parts of a system, hurricane hazard analysis, and consideration of decay of distribution poles. The framework also incorporates cost analysis that considers economic losses due to power outage. A notional power distribution system is used to demonstrate the framework by evaluating and comparing the effectiveness of three hardening measures. - Highlight: • Risk assessment of power distribution systems subjected to hurricanes is carried out. • Framework for studying effectiveness of targeted hardening strategies is presented. • A system reliability method is proposed. • Targeted hardening is cost effective for existing systems. • Economic losses due to power outage should be considered for cost analysis.

  20. Model reduction of nonlinear systems subject to input disturbances

    KAUST Repository

    Ndoye, Ibrahima; Laleg-Kirati, Taous-Meriem

    2017-01-01

    The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order

  1. Model reduction of nonlinear systems subject to input disturbances

    KAUST Repository

    Ndoye, Ibrahima

    2017-07-10

    The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order nonlinear system with similar disturbance-output properties to the original plant. The proposed model reduction strategy preserves the nonlinearity and the input disturbance nature of the model. It guarantees a sufficiently small error between the outputs of the original and the reduced-order systems, and also maintains the properties of input-to-state stability. The matrices of the reduced order system are given in terms of a set of linear matrix inequalities (LMIs). The paper concludes with a demonstration of the proposed approach on model reduction of a nonlinear electronic circuit with additive disturbances.

  2. Two-level method with coarse space size independent convergence

    Energy Technology Data Exchange (ETDEWEB)

    Vanek, P.; Brezina, M. [Univ. of Colorado, Denver, CO (United States); Tezaur, R.; Krizkova, J. [UWB, Plzen (Czech Republic)

    1996-12-31

    The basic disadvantage of the standard two-level method is the strong dependence of its convergence rate on the size of the coarse-level problem. In order to obtain the optimal convergence result, one is limited to using a coarse space which is only a few times smaller than the size of the fine-level one. Consequently, the asymptotic cost of the resulting method is the same as in the case of using a coarse-level solver for the original problem. Today`s two-level domain decomposition methods typically offer an improvement by yielding a rate of convergence which depends on the ratio of fine and coarse level only polylogarithmically. However, these methods require the use of local subdomain solvers for which straightforward application of iterative methods is problematic, while the usual application of direct solvers is expensive. We suggest a method diminishing significantly these difficulties.

  3. Corn silk aqueous extracts and intraocular pressure of systemic and non-systemic hypertensive subjects.

    Science.gov (United States)

    George, Gladys O; Idu, Faustina K

    2015-03-01

    Hypotensive properties have been attributed to the stigma/style of Zea mays L (corn silk). Although the effect of corn silk extract on blood pressure has been documented in animal studies, we are not aware of any study on its effect on human blood pressure and intraocular pressure. A randomised study was carried out on the effect of water only, masked doses of corn silk aqueous extract (60, 130, 192.5 and 260 mg/kg body weight) on intraocular pressure and blood pressure of 20 systemic and 20 non-systemic hypertensive subjects. Intraocular pressure and blood pressure were measured at baseline and every hour for eight hours after administering water or a masked dose of corn silk aqueous extract. Each dose was administered at two-week intervals to each subject in the two study groups. The results showed that the last three doses of corn silk aqueous extract gave a statistically significant reduction (p Corn silk aqueous extract has a lowering effect on intraocular pressure in systemic and non-systemic hypertensive subjects. This may have resulted from the fall in blood pressure that is due to potassium-induced natriuresis and diuresis caused by the high potassium content in the high doses of the corn silk extract. © 2015 The Authors. Clinical and Experimental Optometry © 2015 Optometry Australia.

  4. Construction of a cardiac conduction system subject to extracellular stimulation.

    Science.gov (United States)

    Clements, Clyde; Vigmond, Edward

    2005-01-01

    Proper electrical excitation of the heart is dependent on the specialized conduction system that coordinates the electrical activity from the atria to the ventricles. This paper describes the construction of a conduction system as a branching network of Purkinje fibers on the endocardial surface. Endocardial surfaces were extracted from an FEM model of the ventricles and transformed to 2D. A Purkinje network was drawn on top and the inverse transform performed. The underlying mathematics utilized one dimensional cubic Hermite finite elements. Compared to linear elements, the cubic Hermite solution was found to have a much smaller RMS error. Furthermore, this method has the advantage of enforcing current conservation at bifurcation and unification points, and allows for discrete coupling resistances.

  5. Modal intersection types, two-level languages, and staged synthesis

    DEFF Research Database (Denmark)

    Henglein, Fritz; Rehof, Jakob

    2016-01-01

    -linguistic framework for staged program synthesis, where metaprograms are automatically synthesized which, when executed, generate code in a target language. We survey the basic theory of staged synthesis and illustrate by example how a two-level language theory specialized from λ∩ ⎕ can be used to understand......A typed λ-calculus, λ∩ ⎕, is introduced, combining intersection types and modal types. We develop the metatheory of λ∩ ⎕, with particular emphasis on the theory of subtyping and distributivity of the modal and intersection type operators. We describe how a stratification of λ∩ ⎕ leads to a multi...... the process of staged synthesis....

  6. System reliability of concrete structures subjected to chloride ingress

    DEFF Research Database (Denmark)

    Leira, B.J.; Thöns, Sebastian

    2017-01-01

    attack on the entire bridge, a system model with 90 components is next introduced. This model is employed in order to perform reliability updating based on observations at a number of sites along the bridge. An Enhanced Monte Carlo simulation method (EMC) is applied for this purpose. It is shown...... that application of this simulation method reduces computation times significantly as compared to crude Monte Carlo methods....... are obtained based on measurements from the Gimsøystraumen bridge in Norway. These probability distributions are subsequently employed as input to a prediction model for chloride concentration at the steel reinforcement for a single but arbitrary position along the reinforcement. In order to address chloride...

  7. Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks

    Directory of Open Access Journals (Sweden)

    Fapojuwo Abraham O

    2007-01-01

    Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.

  8. Performance of a Two-Level Call Admission Control Scheme for DS-CDMA Wireless Networks

    Directory of Open Access Journals (Sweden)

    Abraham O. Fapojuwo

    2007-11-01

    Full Text Available We propose a two-level call admission control (CAC scheme for direct sequence code division multiple access (DS-CDMA wireless networks supporting multimedia traffic and evaluate its performance. The first-level admission control assigns higher priority to real-time calls (also referred to as class 0 calls in gaining access to the system resources. The second level admits nonreal-time calls (or class 1 calls based on the resources remaining after meeting the resource needs for real-time calls. However, to ensure some minimum level of performance for nonreal-time calls, the scheme reserves some resources for such calls. The proposed two-level CAC scheme utilizes the delay-tolerant characteristic of non-real-time calls by incorporating a queue to temporarily store those that cannot be assigned resources at the time of initial access. We analyze and evaluate the call blocking, outage probability, throughput, and average queuing delay performance of the proposed two-level CAC scheme using Markov chain theory. The analytic results are validated by simulation results. The numerical results show that the proposed two-level CAC scheme provides better performance than the single-level CAC scheme. Based on these results, it is concluded that the proposed two-level CAC scheme serves as a good solution for supporting multimedia applications in DS-CDMA wireless communication systems.

  9. Elementary Education Program for Engineering by Dual System of Workshop and Teaching Program with Practical Subject

    Science.gov (United States)

    Hara, Toshitsugu

    Elementary education program for engineering by the dual system combined with workshop program and teaching program with practical subject was discussed. The dual system which consists of several workshop programs and fundamental subjects (such as mathematics, English and physics) with practical material has been performed for the freshmen. The elementary workshop program (primary course) has four workshops and the related lectures. Fundamental subjects are taught with the practical or engineering texts. English subjects are taught by specified teachers who have ever worked in engineering field with English. The dual system was supported by such systems as the center for success initiative and the English education center.

  10. Two-level schemes for the advection equation

    Science.gov (United States)

    Vabishchevich, Petr N.

    2018-06-01

    The advection equation is the basis for mathematical models of continuum mechanics. In the approximate solution of nonstationary problems it is necessary to inherit main properties of the conservatism and monotonicity of the solution. In this paper, the advection equation is written in the symmetric form, where the advection operator is the half-sum of advection operators in conservative (divergent) and non-conservative (characteristic) forms. The advection operator is skew-symmetric. Standard finite element approximations in space are used. The standard explicit two-level scheme for the advection equation is absolutely unstable. New conditionally stable regularized schemes are constructed, on the basis of the general theory of stability (well-posedness) of operator-difference schemes, the stability conditions of the explicit Lax-Wendroff scheme are established. Unconditionally stable and conservative schemes are implicit schemes of the second (Crank-Nicolson scheme) and fourth order. The conditionally stable implicit Lax-Wendroff scheme is constructed. The accuracy of the investigated explicit and implicit two-level schemes for an approximate solution of the advection equation is illustrated by the numerical results of a model two-dimensional problem.

  11. Random model of two-level atoms interacting with electromagnetic field

    International Nuclear Information System (INIS)

    Kireev, A.N.; Meleshko, A.N.

    1983-12-01

    A phase transition has been studied in a random system of two-level atoms interacting with an electromagnetic field. It is shown that superradiation can arise when there is short-range order in a spin-subsystem. The existence of long-range order is irrelevant for this phase transition

  12. Breath pacing system and method for pacing the respiratory activity of a subject

    NARCIS (Netherlands)

    2016-01-01

    To provide a breath pacing system and a corresponding method for pacing the respiratory activity of a subject that provide the possibility to adapt the output signal to the respiration characteristics of the subject automatically and effectively a breath pacing system (10) for pacing the respiratory

  13. The Research on Coordinated Decision-Making Method Tax System Based on Subject Data

    Directory of Open Access Journals (Sweden)

    Zhaoji Yu

    2015-01-01

    Full Text Available Academically, the research of subject database of tax system aims to set up an efficient, harmonious virtual data application environment. Subject data, in application and management, has been on demand polymerized and autonomously collaborated and has reached a balance between instantaneity and accuracy. This paper defines the connotation and characteristics enterprise informationization, designs a value system of enterprise informationization which is subject database oriented, and builds a model for the import of the subject database of enterprise informationization. Meantime, this paper describes the structure of the subject database based information import model and forges the model’s theoretical basis of subject data import in tax system. Using the model can make an analysis on the information of data warehouse, storage information, and tax information to provide decision support for the tax administrators.

  14. Pixel detector readout electronics with two-level discriminator scheme

    International Nuclear Information System (INIS)

    Pengg, F.

    1998-01-01

    In preparation for a silicon pixel detector with more than 3,000 readout channels per chip for operation at the future large hadron collider (LHC) at CERN the analog front end of the readout electronics has been designed and measured on several test-arrays with 16 by 4 cells. They are implemented in the HP 0.8 microm process but compatible with the design rules of the radiation hard Honeywell 0.8 microm bulk process. Each cell contains bump bonding pad, preamplifier, discriminator and control logic for masking and testing within a layout area of only 50 microm by 140 microm. A new two-level discriminator scheme has been implemented to cope with the problems of time-walk and interpixel cross-coupling. The measured gain of the preamplifier is 900 mV for a minimum ionizing particle (MIP, about 24,000 e - for a 300 microm thick Si-detector) with a return to baseline within 750 ns for a 1 MIP input signal. The full readout chain (without detector) shows an equivalent noise charge to 60e - r.m.s. The time-walk, a function of the separation between the two threshold levels, is measured to be 22 ns at a separation of 1,500 e - , which is adequate for the 40 MHz beam-crossing frequency at the LHC. The interpixel cross-coupling, measured with a 40fF coupling capacitance, is less than 3%. A single cell consumes 35 microW at 3.5 V supply voltage

  15. Implementation of a Detailed List of Subject Headings on Mormons and Mormonism within the Library of Congress Subject Heading System.

    Science.gov (United States)

    Birkinshaw, Scott B.; Chang, Stella

    Libraries in Utah have collected large numbers of materials on Mormonism and related topics and have a need to provide more detailed subject headings for these materials which the Library of Congress has lumped together under "Mormons and Mormonism." A list of subject headings which was developed for this purpose by a Committee of the…

  16. 47 CFR 76.905 - Standards for identification of cable systems subject to effective competition.

    Science.gov (United States)

    2010-10-01

    ... system. (2) The franchise area is: (i) Served by at least two unaffiliated multichannel video programming... 47 Telecommunication 4 2010-10-01 2010-10-01 false Standards for identification of cable systems... Regulation § 76.905 Standards for identification of cable systems subject to effective competition. (a) Only...

  17. 40 CFR 141.560 - Is my system subject to individual filter turbidity requirements?

    Science.gov (United States)

    2010-07-01

    ... filter turbidity requirements? 141.560 Section 141.560 Protection of Environment ENVIRONMENTAL PROTECTION... Filtration and Disinfection-Systems Serving Fewer Than 10,000 People Individual Filter Turbidity Requirements § 141.560 Is my system subject to individual filter turbidity requirements? If your system is a subpart...

  18. 42 CFR 412.20 - Hospital services subject to the prospective payment systems.

    Science.gov (United States)

    2010-10-01

    ... payment systems. 412.20 Section 412.20 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES Hospital Services Subject to and Excluded From the Prospective Payment Systems for Inpatient...

  19. 42 CFR 419.20 - Hospitals subject to the hospital outpatient prospective payment system.

    Science.gov (United States)

    2010-10-01

    ... prospective payment system. 419.20 Section 419.20 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEM FOR HOSPITAL... Outpatient Prospective Payment System § 419.20 Hospitals subject to the hospital outpatient prospective...

  20. two-level inventory optimization under probability event chain

    African Journals Online (AJOL)

    Journal of Modeling, Design and Management of Engineering Systems ... The paper introduces the concept of effective inventory level, which is used to evaluate the impact of upstream shortage on downstream inventory, models the inventory at warehouse and retailer under random lead time and demand, and makes the ...

  1. Spherical subjective refraction with a novel 3D virtual reality based system

    Directory of Open Access Journals (Sweden)

    Jaume Pujol

    2017-01-01

    Conclusions: The spherical equivalent obtained with the new experimental system was precise and in good agreement with the classical subjective routine. The algorithm implemented in this new system and its optical configuration has been shown to be a first valid step for spherical error correction in a semiautomated way.

  2. A Framework for Control System Design Subject to Average Data-Rate Constraints

    DEFF Research Database (Denmark)

    Silva, Eduardo; Derpich, Milan; Østergaard, Jan

    2011-01-01

    This paper studies discrete-time control systems subject to average data-rate limits. We focus on a situation where a noisy linear system has been designed assuming transparent feedback and, due to implementation constraints, a source-coding scheme (with unity signal transfer function) has to be ...

  3. Optimizing ETL by a Two-level Data Staging Method

    DEFF Research Database (Denmark)

    Liu, Xiufeng; Iftikhar, Nadeem; Nielsen, Per Sieverts

    2016-01-01

    In data warehousing, the data from source systems are populated into a central data warehouse (DW) through extraction, transformation and loading (ETL). The standard ETL approach usually uses sequential jobs to process the data with dependencies, such as dimension and fact data. It is a non......-/late-arriving data, and fast-/slowly-changing data. The introduced additional staging area decouples loading process from data extraction and transformation, which improves ETL flexibility and minimizes intervention to the data warehouse. This paper evaluates the proposed method empirically, which shows...

  4. Thermal analysis of two-level wind power converter under symmetrical grid fault

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede

    2013-01-01

    In this paper, the case of symmetrical grid fault when using the multi-MW wind turbine of partial-scale and full-scale two-level power converter are designed and investigated. Firstly, the different operation behaviors of the relevant power converters under the voltage dip will be described......) condition as well as the junction temperature. For the full-scale wind turbine system, the most thermal stressed power device in the grid-side converter will appear at the grid voltage below 0.5 pu, and for the partial-scale wind turbine system, the most thermal stressed power device in the rotor...

  5. On Inventory Control For Perishable Inventory Systems Subject To Uncertainties On Customer Demands

    OpenAIRE

    Abbou , Rosa; Loiseau , Jean-Jacques; Khaldi , Hajer; Farraa , Berna ,

    2017-01-01

    International audience; This paper deals with the inventory controller design for constrained production systems subject to uncertainties on the customer demands. The case study focuses on the inventory regulation problem in production systems where contain perishable finite products. Such systems are characterized by the presence of delays due to production processes, and constraints from the instantaneous inventory level, production level and the finite capacities of stocks. To do that, we ...

  6. DDC in DSpace: Integration of Multi-lingual Subject Access System in Institutional Digital Repositories

    Directory of Open Access Journals (Sweden)

    Bijan Kumar Roy

    2017-12-01

    Full Text Available The paper discusses the nature of Knowledge Organization Systems (KOSs and shows how these can support digital library users. It demonstrates processes related to integration of KOS like the Dewey Decimal Classification, 22nd edition (DDC22 in DSpace software (http://www.dspace.org/ for organizing and retrieving (browsing and searching scholarly objects. An attempt has been made to use the DDC22 available in Bengali language and highlights the required mechanisms for system-level integration. It may help repository administrator to build IDR (Institutional Digital Repository integrated with SKOS-enabled multilingual subject access systems for supporting subject descriptors based indexing (DC.Subject metadata element, structured navigation (browsing and efficient searching.

  7. Spherical subjective refraction with a novel 3D virtual reality based system.

    Science.gov (United States)

    Pujol, Jaume; Ondategui-Parra, Juan Carlos; Badiella, Llorenç; Otero, Carles; Vilaseca, Meritxell; Aldaba, Mikel

    To conduct a clinical validation of a virtual reality-based experimental system that is able to assess the spherical subjective refraction simplifying the methodology of ocular refraction. For the agreement assessment, spherical refraction measurements were obtained from 104 eyes of 52 subjects using three different methods: subjectively with the experimental prototype (Subj.E) and the classical subjective refraction (Subj.C); and objectively with the WAM-5500 autorefractor (WAM). To evaluate precision (intra- and inter-observer variability) of each refractive tool independently, 26 eyes were measured in four occasions. With regard to agreement, the mean difference (±SD) for the spherical equivalent (M) between the new experimental subjective method (Subj.E) and the classical subjective refraction (Subj.C) was -0.034D (±0.454D). The corresponding 95% Limits of Agreement (LoA) were (-0.856D, 0.924D). In relation to precision, intra-observer mean difference for the M component was 0.034±0.195D for the Subj.C, 0.015±0.177D for the WAM and 0.072±0.197D for the Subj.E. Inter-observer variability showed worse precision values, although still clinically valid (below 0.25D) in all instruments. The spherical equivalent obtained with the new experimental system was precise and in good agreement with the classical subjective routine. The algorithm implemented in this new system and its optical configuration has been shown to be a first valid step for spherical error correction in a semiautomated way. Copyright © 2016 Spanish General Council of Optometry. Published by Elsevier España, S.L.U. All rights reserved.

  8. Remaining useful life prediction of degrading systems subjected to imperfect maintenance: Application to draught fans

    Science.gov (United States)

    Wang, Zhao-Qiang; Hu, Chang-Hua; Si, Xiao-Sheng; Zio, Enrico

    2018-02-01

    Current degradation modeling and remaining useful life prediction studies share a common assumption that the degrading systems are not maintained or maintained perfectly (i.e., to an as-good-as new state). This paper concerns the issues of how to model the degradation process and predict the remaining useful life of degrading systems subjected to imperfect maintenance activities, which can restore the health condition of a degrading system to any degradation level between as-good-as new and as-bad-as old. Toward this end, a nonlinear model driven by Wiener process is first proposed to characterize the degradation trajectory of the degrading system subjected to imperfect maintenance, where negative jumps are incorporated to quantify the influence of imperfect maintenance activities on the system's degradation. Then, the probability density function of the remaining useful life is derived analytically by a space-scale transformation, i.e., transforming the constructed degradation model with negative jumps crossing a constant threshold level to a Wiener process model crossing a random threshold level. To implement the proposed method, unknown parameters in the degradation model are estimated by the maximum likelihood estimation method. Finally, the proposed degradation modeling and remaining useful life prediction method are applied to a practical case of draught fans belonging to a kind of mechanical systems from steel mills. The results reveal that, for a degrading system subjected to imperfect maintenance, our proposed method can obtain more accurate remaining useful life predictions than those of the benchmark model in literature.

  9. A Weighted Two-Level Bregman Method with Dictionary Updating for Nonconvex MR Image Reconstruction

    Directory of Open Access Journals (Sweden)

    Qiegen Liu

    2014-01-01

    Full Text Available Nonconvex optimization has shown that it needs substantially fewer measurements than l1 minimization for exact recovery under fixed transform/overcomplete dictionary. In this work, two efficient numerical algorithms which are unified by the method named weighted two-level Bregman method with dictionary updating (WTBMDU are proposed for solving lp optimization under the dictionary learning model and subjecting the fidelity to the partial measurements. By incorporating the iteratively reweighted norm into the two-level Bregman iteration method with dictionary updating scheme (TBMDU, the modified alternating direction method (ADM solves the model of pursuing the approximated lp-norm penalty efficiently. Specifically, the algorithms converge after a relatively small number of iterations, under the formulation of iteratively reweighted l1 and l2 minimization. Experimental results on MR image simulations and real MR data, under a variety of sampling trajectories and acceleration factors, consistently demonstrate that the proposed method can efficiently reconstruct MR images from highly undersampled k-space data and presents advantages over the current state-of-the-art reconstruction approaches, in terms of higher PSNR and lower HFEN values.

  10. Protecting quantum coherence of two-level atoms from vacuum fluctuations of electromagnetic field

    International Nuclear Information System (INIS)

    Liu, Xiaobao; Tian, Zehua; Wang, Jieci; Jing, Jiliang

    2016-01-01

    In the framework of open quantum systems, we study the dynamics of a static polarizable two-level atom interacting with a bath of fluctuating vacuum electromagnetic field and explore under which conditions the coherence of the open quantum system is unaffected by the environment. For both a single-qubit and two-qubit systems, we find that the quantum coherence cannot be protected from noise when the atom interacts with a non-boundary electromagnetic field. However, with the presence of a boundary, the dynamical conditions for the insusceptible of quantum coherence are fulfilled only when the atom is close to the boundary and is transversely polarizable. Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction. -- Highlights: •We study the dynamics of a two-level atom interacting with a bath of fluctuating vacuum electromagnetic field. •For both a single and two-qubit systems, the quantum coherence cannot be protected from noise without a boundary. •The insusceptible of the quantum coherence can be fulfilled only when the atom is close to the boundary and is transversely polarizable. •Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction.

  11. On reliability of system composed from parallel units subject to increasing load

    Czech Academy of Sciences Publication Activity Database

    Volf, Petr; Linka, A.

    2000-01-01

    Roč. 7, č. 4 (2000), s. 271-284 ISSN 0218-5393 R&D Projects: GA MŠk VS97084 Institutional research plan: AV0Z1075907 Keywords : reliability * mathematical statistics * parallel system Subject RIV: BB - Applied Statistics, Operational Research

  12. Asymptotic stability of discrete-time systems with time-varying delay subject to saturation nonlinearities

    International Nuclear Information System (INIS)

    Chen, S.-F.

    2009-01-01

    The asymptotic stability problem for discrete-time systems with time-varying delay subject to saturation nonlinearities is addressed in this paper. In terms of linear matrix inequalities (LMIs), a delay-dependent sufficient condition is derived to ensure the asymptotic stability. A numerical example is given to demonstrate the theoretical results.

  13. Methods of Information Subjects and Objects Interaction Rules Formalization in the Electronic Trading Platform System

    Directory of Open Access Journals (Sweden)

    Emma Emanuilova Yandybaeva

    2015-03-01

    Full Text Available The methods of information subjects and objects interaction rules formalization in the electronic trading platform system has been developed. They are based on mathematical model of mandatory role-based access control. As a result of the work we have defined set of user roles and constructed roles hierarchy. For the roles hierarchy restrictions have been imposed to ensure the safety of the information system.

  14. State-Feedback Control for Fractional-Order Nonlinear Systems Subject to Input Saturation

    Directory of Open Access Journals (Sweden)

    Junhai Luo

    2014-01-01

    Full Text Available We give a state-feedback control method for fractional-order nonlinear systems subject to input saturation. First, a sufficient condition is derived for the asymptotical stability of a class of fractional-order nonlinear systems. Then based on Gronwall-Bellman lemma and a sector bounded condition of the saturation function, a linear state-feed back controller is designed. Finally, two simulation examples are presented to show the validity of the proposed method.

  15. Quantum averaging and resonances: two-level atom in a one-mode classical laser field

    Directory of Open Access Journals (Sweden)

    M. Amniat-Talab

    2007-06-01

    Full Text Available   We use a nonperturbative method based on quantum averaging and an adapted from of resonant transformations to treat the resonances of the Hamiltonian of a two-level atom interacting with a one-mode classical field in Floquet formalism. We illustrate this method by extraction of effective Hamiltonians of the system in two regimes of weak and strong coupling. The results obtained in the strong-coupling regime, are valid in the whole range of the coupling constant for the one-photon zero-field resonance.

  16. Oscillations of Doppler-Raby of two level atom moving in resonator

    International Nuclear Information System (INIS)

    Kozlovskij, A.V.

    2001-01-01

    The interaction of the two-level atom with the quantum mode of the high-quality resonator uniformly moving by the classic trajectory, is considered. The recurrent formula for the probability of the atom transition with the photon radiation is determined through the dressed states method. It is shown, that the ratio between the Doppler shift value of the atom transition and the Raby frequency value of the atom-field system qualitatively effects the dependence of the moving atom transition probability on its position in the resonator, as well as on its value [ru

  17. Limitations of two-level emitters as nonlinearities in two-photon controlled-PHASE gates

    DEFF Research Database (Denmark)

    Nysteen, Anders; McCutcheon, Dara P. S.; Heuck, Mikkel

    2017-01-01

    We investigate the origin of imperfections in the fidelity of a two-photon controlled-PHASE gate based on two-level-emitter nonlinearities. We focus on a passive system that operates without external modulations to enhance its performance. We demonstrate that the fidelity of the gate is limited...... by opposing requirements on the input pulse width for one-and two-photon-scattering events. For one-photon scattering, the spectral pulse width must be narrow compared with the emitter linewidth, while two-photon-scattering processes require the pulse width and emitter linewidth to be comparable. We find...

  18. Probe transparency in a two-level medium embedded by a squeezed vacuum

    International Nuclear Information System (INIS)

    Swain, S.; Zhou, P.

    1994-08-01

    Effect of the detuning on the probe absorption spectra of a two-level system with and without a classically driven field in a squeezed vacuum is investigated. For a strong squeezing, there is a threshold which determines the positions and widths of the absorption peaks, for the squeezed parameter M. In a large detuning, the spectra exhibit some resemblance to the Fano spectrum. The squeezing-induced transparency occurs at the frequency 2ω L - ω A in the minimum-uncertainty squeezed vacuum. This effect is not phase-sensitive. (author). 15 refs, 8 figs

  19. Subjective and objective analysis of three water pump systems carried by forest firefighters.

    Science.gov (United States)

    Moser, Daniel J; Graham, Ryan B; Stevenson, Joan M; Costigan, Patrick A

    2014-01-01

    The Mark 3 (M3) water power pump is an integral piece of wildfire fighting equipment. However, it is provided to fire stations without a carrying harness. The currently-used carrying harness is very uncomfortable, especially when carrying the pumps considerable distance in a forest to reach a water source. The purpose of this study was to advise the Ontario Ministry of Natural Resources on the selection of a new M3 load carriage system. Twenty Fire Rangers wore the three systems (Original, Prototype, and Modified) through a circuit of tasks representative of their working environment. Subjective and objective approaches were combined to assess and rank the M3 carriage systems. Subjective visual analogue scale ratings were obtained for ease of loading/unloading, comfort, system stability, and overall performance. Tri-axial accelerometers were mounted on each pump and at the sternum of each participant to determine relative pump-carrier accelerations. Overall, the Prototype was ranked as the best system; it resulted in the lowest relative pump-carrier accelerations on 10 out of 15 objective measures, and also received a first place ranking on all subjective measures. It was recommended that the Prototype be implemented as the M3 carriage system for fire suppression teams.

  20. Seismic response analysis of structural system subjected to multiple support excitation

    International Nuclear Information System (INIS)

    Wu, R.W.; Hussain, F.A.; Liu, L.K.

    1978-01-01

    In the seismic analysis of a multiply supported structural system subjected to nonuniform excitations at each support point, the single response spectrum, the time history, and the multiple response spectrum are the three commonly employed methods. In the present paper the three methods are developed, evaluated, and the limitations and advantages of each method assessed. A numerical example has been carried out for a typical piping system. Considerably smaller responses have been predicted by the time history method than that by the single response spectrum method. This is mainly due to the fact that the phase and amplitude relations between the support excitations are faithfully retained in the time history method. The multiple response spectrum prediction has been observed to compare favourably with the time history method prediction. Based on the present evaluation, the multiple response spectrum method is the most efficient method for seismic response analysis of structural systems subjected to multiple support excitation. (Auth.)

  1. Inelastic response of piping systems subjected to in-structure seismic excitation

    International Nuclear Information System (INIS)

    Campbell, R.D.; Kennedy, R.P.; Trasher, R.D.

    1983-01-01

    A study was undertaken to examine the inelastic response of single-degree-of-freedom systems and a simple piping system to varying levels of earthquake loading with superimposed static loading. The objective was to examine the conservatism inherent in ASME code rules for the design of piping systems by quantifying the ratio of the dynamic margin to the static margin for various degrees of inelastic strain, system frequencies and instructure time histories. Previous studies of elastic, perfectly-plastic and bilinear strain-hardening, single-degree-of-freedom models subjected to earthquake ground motion records have demonstrated the conservatism in current design methodology and design codes for earthquake resistant design of structures. This study compares response of single degree of freedom and simple piping system subjected to typical in-structure earthquake time histories and focuses on the excess margin inherent in current design criteria for piping systems. It is shown that the factor of safety against failure is variable and is dependent upon the frequency content of the loading, the dynamic characteristics of the piping system and the allowable system ductility. A recommendation is made for revision to current criteria on the basis of maintaining a constant factor of safety for dynamic and static loading

  2. The Implications of Contamination for Educational Experiments with Two Levels of Nesting

    Science.gov (United States)

    Rhoads, Christopher

    2016-01-01

    Experimental evaluations that involve the educational system usually involve a hierarchical structure (students are nested within classrooms that are nested within schools, etc.). Concerns about contamination, where research subjects receive certain features of an intervention intended for subjects in a different experimental group, have often led…

  3. Classification of Normal Subjects and Pulmonary Function Disease Patients using Tracheal Respiratory Sound Detection System

    Energy Technology Data Exchange (ETDEWEB)

    Im, Jae Joong; Yi, Young Ju; Jeon, Young Ju [Chonbuk National University (Korea)

    2000-04-01

    A new auscultation system for the detection of breath sound from trachea was developed in house. Small size microphone(panasonic pin microphone) was encapsuled in a housing for resonant effect, and hardware for the sound detection was fabricated. Pulmonary function test results were compared with the parameters extracted from frequency spectrum of breath sound obtained from the developed system. Results showed that the peak frequency and relative ratio of integral values between low(80-400Hz) and high(400-800Hz) frequency ranges revealed the significant differences. Developed system could be used for distinguishing normal subject and the patients who have pulmonary disease. (author). 13 refs., 9 figs.

  4. MR-based trabecular bone microstructure is not altered in subjects with indolent systemic mastocytosis.

    Science.gov (United States)

    Baum, Thomas; Karampinos, Dimitrios C; Brockow, Knut; Seifert-Klauss, Vanadin; Jungmann, Pia M; Biedermann, Tilo; Rummeny, Ernst J; Bauer, Jan S; Müller, Dirk

    2015-01-01

    Subjects with indolent systemic mastocytosis (ISM) have an increased risk for osteoporosis. It has been demonstrated that trabecular bone microstructure analysis improves the prediction of bone strength beyond dual-energy X-ray absorptiometry-based bone mineral density. The purpose of this study was to obtain Magnetic Resonance (MR)-based trabecular bone microstructure parameters as advanced imaging biomarkers in subjects with ISM (n=18) and compare them with those of normal controls (n=18). Trabecular bone microstructure parameters were not significantly (P>.05) different between subjects with ISM and controls. These findings revealed important pathophysiological information about ISM-associated osteoporosis and may limit the use of trabecular bone microstructure analysis in this clinical setting. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Feasibility of a smartphone-based balance assessment system for subjects with chronic stroke.

    Science.gov (United States)

    Hou, You-Ruei; Chiu, Ya-Lan; Chiang, Shang-Lin; Chen, Hui-Ya; Sung, Wen-Hsu

    2018-07-01

    Stroke is a cerebral artery disease that may lead to long-term disabilities or death. Patients that survive a stroke usually suffer balance impairments, which affect their performance in activities of daily living (ADLs) and quality of life (QoL). In recent years, smartphones have become very popular and have many capabilities. Smartphone built-in sensors have shown their ability and potential in balance performance assessment. However, the feasibility of smartphones on subjects with chronic strokes remains to be proved. Therefore, the purpose of this study is to evaluate the feasibility of a smartphone-based balance assessment system for subjects with chronic stroke. Ten subjects with chronic stroke and thirteen healthy adults were recruited in the study. The smartphone HTC 10 (HTC Corporation, Taiwan) was used to perform the balance assessment, and its built-in accelerometer and gyroscope were used to record data from the subjects. Six postures were tested for thirty seconds each: shoulder-width stance (SWS) with eyes opened (E/O) and eyes closed (E/C), feet-together stance (FTS) with E/O and E/C, and semi-tandem stance (STS) with E/O and E/C. The smartphone was fixed to the back of subjects at the second sacral spine (S2) level. The changes registered in the accelerometer and gyroscope data were used to represent the balance performance, in which higher values indicate more instability. Data was analyzed using the independent t-test with the software SPSS 20, and the statistical significance level was set to α balance performances between healthy adults and subjects with chronic stroke. This study shows that smartphones are feasible to assess balance for subjects with chronic stroke. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Two-level Robust Measurement Fusion Kalman Filter for Clustering Sensor Networks

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; QI Wen-Juan; DENG Zi-Li

    2014-01-01

    This paper investigates the distributed fusion Kalman filtering over clustering sensor networks. The sensor network is partitioned as clusters by the nearest neighbor rule and each cluster consists of sensing nodes and cluster-head. Using the minimax robust estimation principle, based on the worst-case conservative system with the conservative upper bounds of noise variances, two-level robust measurement fusion Kalman filter is presented for the clustering sensor network systems with uncertain noise variances. It can significantly reduce the communication load and save energy when the number of sensors is very large. A Lyapunov equation approach for the robustness analysis is presented, by which the robustness of the local and fused Kalman filters is proved. The concept of the robust accuracy is presented, and the robust accuracy relations among the local and fused robust Kalman filters are proved. It is proved that the robust accuracy of the two-level weighted measurement fuser is equal to that of the global centralized robust fuser and is higher than those of each local robust filter and each local weighted measurement fuser. A simulation example shows the correctness and effectiveness of the proposed results.

  7. Combinatorial analysis of systems with competing failures subject to failure isolation and propagation effects

    International Nuclear Information System (INIS)

    Xing Liudong; Levitin, Gregory

    2010-01-01

    This paper considers the reliability analysis of binary-state systems, subject to propagated failures with global effect, and failure isolation phenomena. Propagated failures with global effect are common-cause failures originated from a component of a system/subsystem causing the failure of the entire system/subsystem. Failure isolation occurs when the failure of one component (referred to as a trigger component) causes other components (referred to as dependent components) within the same system to become isolated from the system. On the one hand, failure isolation makes the isolated dependent components unusable; on the other hand, it prevents the propagation of failures originated from those dependent components. However, the failure isolation effect does not exist if failures originated in the dependent components already propagate globally before the trigger component fails. In other words, there exists a competition in the time domain between the failure of the trigger component that causes failure isolation and propagated failures originated from the dependent components. This paper presents a combinatorial method for the reliability analysis of systems subject to such competing propagated failures and failure isolation effect. Based on the total probability theorem, the proposed method is analytical, exact, and has no limitation on the type of time-to-failure distributions for the system components. An illustrative example is given to demonstrate the basics and advantages of the proposed method.

  8. A Subjective Evaluation of the Minimum Audible Channel Separation in Binaural Reproduction Systems Through Loudspeakers

    DEFF Research Database (Denmark)

    Lacouture Parodi, Yesenia; Rubak, Per

    2010-01-01

    To evaluate the performance of crosstalk cancellation systems the channel separation is usually used as parameter.  However, no systematic evaluation of the minimum audible channel separation has been found in the literature known by the authors.  This paper describes a set of subjective experime......To evaluate the performance of crosstalk cancellation systems the channel separation is usually used as parameter.  However, no systematic evaluation of the minimum audible channel separation has been found in the literature known by the authors.  This paper describes a set of subjective...... simulated.  Results indicate that  in order to avoid lateralization the  channel separation should be below -15dB for most of the stimuli and around -20dB for broad-band noise....

  9. Laboratory study of subjective perceptions to low temperature heating systems with exhaust ventilation in Nordic countries

    DEFF Research Database (Denmark)

    Jin, Quan; Simone, Angela; Olesen, Bjarne W.

    2017-01-01

    Given the global trends of rising energy demand and the increasing utilization of low-grade renewable energy, low-temperature heating systems can play key roles in improving building energy efficiency while providing a comfortable indoor environment. To meet the need to retrofit existing buildings...... in Nordic countries for greater energy efficiency, this study focused on human subjects’ thermal sensation, thermal comfort, thermal acceptability, draft acceptability, and perceived air quality when three low-temperature heating systems were used: conventional radiator, ventilation radiator, or floor...... heating with exhaust ventilation. Human subject tests were carried out in the climate chamber at the Technical University of Denmark. In total, 24 human subjects, 12 females and 12 males, participated in the tests during the winter season. The results show that no significant differences in thermal...

  10. The Population Inversion and the Entropy of a Moving Two-Level Atom in Interaction with a Quantized Field

    Science.gov (United States)

    Abo-Kahla, D. A. M.; Abdel-Aty, M.; Farouk, A.

    2018-05-01

    An atom with only two energy eigenvalues is described by a two-dimensional state space spanned by the two energy eigenstates is called a two-level atom. We consider the interaction between a two-level atom system with a constant velocity. An analytic solution of the systems which interacts with a quantized field is provided. Furthermore, the significant effect of the temperature on the atomic inversion, the purity and the information entropy are discussed in case of the initial state either an exited state or a maximally mixed state. Additionally, the effect of the half wavelengths number of the field-mode is investigated.

  11. Predictive maintenance policy for a gradually deteriorating system subject to stress

    Energy Technology Data Exchange (ETDEWEB)

    Deloux, E. [IRCCyN/Ecole des Mines de Nantes, Nantes (France); Castanier, B. [IRCCyN/Ecole des Mines de Nantes, Nantes (France)], E-mail: bruno.castanier@emn.fr; Berenguer, C. [Universite de Technologie de Troyes/CNRS, Troyes (France)

    2009-02-15

    This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters.

  12. Predictive maintenance policy for a gradually deteriorating system subject to stress

    International Nuclear Information System (INIS)

    Deloux, E.; Castanier, B.; Berenguer, C.

    2009-01-01

    This paper deals with a predictive maintenance policy for a continuously deteriorating system subject to stress. We consider a system with two failure mechanisms which are, respectively, due to an excessive deterioration level and a shock. To optimize the maintenance policy of the system, an approach combining statistical process control (SPC) and condition-based maintenance (CBM) is proposed. CBM policy is used to inspect and replace the system according to the observed deterioration level. SPC is used to monitor the stress covariate. In order to assess the performance of the proposed maintenance policy and to minimize the long-run expected maintenance cost per unit of time, a mathematical model for the maintained system cost is derived. Analysis based on numerical results are conducted to highlight the properties of the proposed maintenance policy in respect to the different maintenance parameters

  13. Low-frequency dynamics of autonomic regulation of circulatory system in healthy subjects

    Science.gov (United States)

    Skazkina, V. V.; Borovkova, E. I.; Galushko, T. A.; Khorev, V. S.; Kiselev, A. R.

    2018-04-01

    The paper is devoted to the analysis of dynamic of interactions between signals of autonomic circulatory regulation. We investigated two-hour experimental records of 30 healthy people. Phase synchronization was studied using the signals of the electrocardiogram and the photoplethysmogram of vessels. We found the presence of long synchronous intervals in some subjects. For analysis of the dynamic we calculated autocorrelation functions. The analysis made it possible to reveal indirect signs of the influence of the humoral regulation system.

  14. Tracking Systems for Virtual Rehabilitation: Objective Performance vs. Subjective Experience. A Practical Scenario

    Directory of Open Access Journals (Sweden)

    Roberto Lloréns

    2015-03-01

    Full Text Available Motion tracking systems are commonly used in virtual reality-based interventions to detect movements in the real world and transfer them to the virtual environment. There are different tracking solutions based on different physical principles, which mainly define their performance parameters. However, special requirements have to be considered for rehabilitation purposes. This paper studies and compares the accuracy and jitter of three tracking solutions (optical, electromagnetic, and skeleton tracking in a practical scenario and analyzes the subjective perceptions of 19 healthy subjects, 22 stroke survivors, and 14 physical therapists. The optical tracking system provided the best accuracy (1.074 ± 0.417 cm while the electromagnetic device provided the most inaccurate results (11.027 ± 2.364 cm. However, this tracking solution provided the best jitter values (0.324 ± 0.093 cm, in contrast to the skeleton tracking, which had the worst results (1.522 ± 0.858 cm. Healthy individuals and professionals preferred the skeleton tracking solution rather than the optical and electromagnetic solution (in that order. Individuals with stroke chose the optical solution over the other options. Our results show that subjective perceptions and preferences are far from being constant among different populations, thus suggesting that these considerations, together with the performance parameters, should be also taken into account when designing a rehabilitation system.

  15. System of Indicators of the Level of Costs of Financing an Economic Subject

    Directory of Open Access Journals (Sweden)

    Laktionova Aleksandra A.

    2013-11-01

    Full Text Available The article offers a system of indicators of the level of costs of financing economic subjects, in the basis of which there is a function of formation of recommendations or identification of directions and priorities in the part of selection of one or another source of financing, its urgency and specific features of attraction of resources, on the basis of information on the level of agent’s costs, information asymmetry costs, financial instability, transaction and market indicators of cost of financial resources. The article pays a special attention to a significant structure forming factor of the ownership structure, which identifies the volume and logic of interconnection of all costs of financing and determining incentives and risks in the system of management of financial activity of an economic subject from the point of view of all participants. It exerts especially big influence upon formation of such implicit costs of financing as agent’s costs and information asymmetry costs. The system of factors of stimulants and de-stimulants of costs of financing includes factors of external environment (macro-economic and market indicators of cost and institutional provision and internal environment (ownership structure, characteristic of investment activity and financing an economic subject, organisation of business and corporate management.

  16. Canyon of current suppression in an interacting two-level quantum dot

    DEFF Research Database (Denmark)

    Karlström, O; Pedersen, Jonas Nyvold; Samuelsson, P

    2011-01-01

    Motivated by the recent discovery of a canyon of conductance suppression in a two-level equal-spin quantum dot system [Phys. Rev. Lett. 104, 186804 (2010)], the transport through this system is studied in detail. At low bias and low temperature a strong current suppression is found around...... the electron-hole symmetry point independent of the couplings, in agreement with previous results. By means of a Schrieffer–Wolff transformation we are able to give an intuitive explanation to this suppression in the low-energy regime. In the general situation, numerical simulations are carried out using...... for the current suppression. It is also shown how broadening, interference, and a finite interaction energy cause a shift of the current minimum away from degeneracy. Finally we see how an increased population of the upper level leads to current peaks on each side of the suppression line. At sufficiently high...

  17. Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

    International Nuclear Information System (INIS)

    Liu Jia; Chen Ziyu; Bu Shenping; Zhang Guofeng

    2009-01-01

    Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.

  18. Two-Level Hierarchical FEM Method for Modeling Passive Microwave Devices

    Science.gov (United States)

    Polstyanko, Sergey V.; Lee, Jin-Fa

    1998-03-01

    In recent years multigrid methods have been proven to be very efficient for solving large systems of linear equations resulting from the discretization of positive definite differential equations by either the finite difference method or theh-version of the finite element method. In this paper an iterative method of the multiple level type is proposed for solving systems of algebraic equations which arise from thep-version of the finite element analysis applied to indefinite problems. A two-levelV-cycle algorithm has been implemented and studied with a Gauss-Seidel iterative scheme used as a smoother. The convergence of the method has been investigated, and numerical results for a number of numerical examples are presented.

  19. Phonon induced optical gain in a current carrying two-level quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Eskandari-asl, Amir, E-mail: amir.eskandari.asl@gmail.com [Department of Physics, Shahid Beheshti University, G.C. Evin, Tehran 1983963113 (Iran, Islamic Republic of); School of Nano Science, Institute for Research in Fundamental Sciences (IPM), P.O. Box: 19395-5531, Tehran, Iran (Iran, Islamic Republic of)

    2017-05-15

    In this work we consider a current carrying two level quantum dot (QD) that is coupled to a single mode phonon bath. Using self-consistent Hartree-Fock approximation, we obtain the I-V curve of QD. By considering the linear response of our system to an incoming classical light, we see that depending on the parametric regime, the system could have weak or strong light absorption or may even show lasing. This lasing occurs at high enough bias voltages and is explained by a population inversion considering side bands, while the total electron population in the higher level is less than the lower one. The frequency at which we have the most significant lasing depends on the level spacing and phonon frequency and not on the electron-phonon coupling strength.

  20. Two-level modulation scheme to reduce latency for optical mobile fronthaul networks.

    Science.gov (United States)

    Sung, Jiun-Yu; Chow, Chi-Wai; Yeh, Chien-Hung; Chang, Gee-Kung

    2016-10-31

    A system using optical two-level orthogonal-frequency-division-multiplexing (OFDM) - amplitude-shift-keying (ASK) modulation is proposed and demonstrated to reduce the processing latency for the optical mobile fronthaul networks. At the proposed remote-radio-head (RRH), the high data rate OFDM signal does not need to be processed, but is directly launched into a high speed photodiode (HSPD) and subsequently emitted by an antenna. Only a low bandwidth PD is needed to recover the low data rate ASK control signal. Hence, it is simple and provides low-latency. Furthermore, transporting the proposed system over the already deployed optical-distribution-networks (ODNs) of passive-optical-networks (PONs) is also demonstrated with 256 ODN split-ratios.

  1. Spatial aspects of sound quality - and by multichannel systems subjective assessment of sound reproduced by stereo

    DEFF Research Database (Denmark)

    Choisel, Sylvain

    the fidelity with which sound reproduction systems can re-create the desired stereo image, a laser pointing technique was developed to accurately collect subjects' responses in a localization task. This method is subsequently applied in an investigation of the effects of loudspeaker directivity...... on the perceived direction of panned sources. The second part of the thesis addresses the identification of auditory attributes which play a role in the perception of sound reproduced by multichannel systems. Short musical excerpts were presented in mono, stereo and several multichannel formats to evoke various...

  2. Development and evaluation of a two-level functional structure for the thin film encapsulation

    International Nuclear Information System (INIS)

    Lee, Jae-Wung; Sharma, Jaibir; Singh, Navab; Kwong, Dim-Lee

    2013-01-01

    This paper reports a two level capping structure for encapsulating micro-electro-mechanical system (MEMS) devices. The two level capping solves the main issue of the longer release time as well as safe sealing in thin film encapsulation (TFE). In this technique, the first cap layer has many etch holes, which were uniformly distributed on it to enhance the removal of the sacrificial layer. The second cap layer forms a cap on every etch hole in the first cap layer to protect the mass loading on MEMS devices. This technique was found to be very effective in reducing the release time of the TFE. For the 1200 µm × 1200 µm sized cavity encapsulation, this technique decreases the release time of the TFE by a factor of 24 in comparison to the sidewall located channel scheme. The presented technique also helps in reducing the size of TFE as the etch holes are uniformly distributed on the TFE itself. Wide seal rings were not required to accommodate sidewall channels. (paper)

  3. Ramsey interferometry with a two-level generalized Tonks-Girardeau gas

    International Nuclear Information System (INIS)

    Mousavi, S. V.; Campo, A. del; Lizuain, I.; Muga, J. G.

    2007-01-01

    We propose a solvable generalization of the Tonks-Girardeau model that describes a coherent one-dimensional (1D) gas of cold two-level bosons which interact with two external fields in a Ramsey interferometer. They also interact among themselves by idealized, infinitely strong contact potentials, with interchange of momentum and internal state. We study the corresponding Ramsey fringes and the quantum projection noise which, essentially unaffected by the interactions, remains that for ideal bosons. The dual system of this gas, an ideal gas of two-level fermions coupled by the interaction with the separated fields, produces the same fringes and noise fluctuations. The cases of time-separated and spatially separated fields are studied. For spatially separated fields the fringes may be broadened slightly by increasing the number of particles, but only for large particle numbers far from present experiments with Tonks-Girardeau gases. The uncertainty in the determination of the atomic transition frequency diminishes, essentially with the inverse root of the particle number. The difficulties to implement the model experimentally and possible shortcomings of strongly interacting 1D gases for frequency standards and atomic clocks are discussed

  4. Safety of the HyperSound® Audio System in subjects with normal hearing

    Directory of Open Access Journals (Sweden)

    Ritvik P. Mehta

    2015-11-01

    Full Text Available The objective of the study was to assess the safety of the HyperSound® Audio System (HSS, a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered preexposure and post-exposure test design. We investigated primary and secondary outcome measures: i temporary threshold shift (TTS, defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs >10 dB at two or more frequencies; ii presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

  5. Safety of the HyperSound® Audio System in Subjects with Normal Hearing.

    Science.gov (United States)

    Mehta, Ritvik P; Mattson, Sara L; Kappus, Brian A; Seitzman, Robin L

    2015-06-11

    The objective of the study was to assess the safety of the HyperSound® Audio System (HSS), a novel audio system using ultrasound technology, in normal hearing subjects under normal use conditions; we considered pre-exposure and post-exposure test design. We investigated primary and secondary outcome measures: i) temporary threshold shift (TTS), defined as >10 dB shift in pure tone air conduction thresholds and/or a decrement in distortion product otoacoustic emissions (DPOAEs) >10 dB at two or more frequencies; ii) presence of new-onset otologic symptoms after exposure. Twenty adult subjects with normal hearing underwent a pre-exposure assessment (pure tone air conduction audiometry, tympanometry, DPOAEs and otologic symptoms questionnaire) followed by exposure to a 2-h movie with sound delivered through the HSS emitter followed by a post-exposure assessment. No TTS or new-onset otological symptoms were identified. HSS demonstrates excellent safety in normal hearing subjects under normal use conditions.

  6. Seismic Response of Power Transmission Tower-Line System Subjected to Spatially Varying Ground Motions

    Directory of Open Access Journals (Sweden)

    Li Tian

    2010-01-01

    Full Text Available The behavior of power transmission tower-line system subjected to spatially varying base excitations is studied in this paper. The transmission towers are modeled by beam elements while the transmission lines are modeled by cable elements that account for the nonlinear geometry of the cables. The real multistation data from SMART-1 are used to analyze the system response subjected to spatially varying ground motions. The seismic input waves for vertical and horizontal ground motions are also generated based on the Code for Design of Seismic of Electrical Installations. Both the incoherency of seismic waves and wave travel effects are accounted for. The nonlinear time history analytical method is used in the analysis. The effects of boundary conditions, ground motion spatial variations, the incident angle of the seismic wave, coherency loss, and wave travel on the system are investigated. The results show that the uniform ground motion at all supports of system does not provide the most critical case for the response calculations.

  7. Spatial Domain Adaptive Control of Nonlinear Rotary Systems Subject to Spatially Periodic Disturbances

    Directory of Open Access Journals (Sweden)

    Yen-Hsiu Yang

    2012-01-01

    Full Text Available We propose a generic spatial domain control scheme for a class of nonlinear rotary systems of variable speeds and subject to spatially periodic disturbances. The nonlinear model of the rotary system in time domain is transformed into one in spatial domain employing a coordinate transformation with respect to angular displacement. Under the circumstances that measurement of the system states is not available, a nonlinear state observer is established for providing the estimated states. A two-degree-of-freedom spatial domain control configuration is then proposed to stabilize the system and improve the tracking performance. The first control module applies adaptive backstepping with projected parametric update and concentrates on robust stabilization of the closed-loop system. The second control module introduces an internal model of the periodic disturbances cascaded with a loop-shaping filter, which not only further reduces the tracking error but also improves parametric adaptation. The overall spatial domain output feedback adaptive control system is robust to model uncertainties and state estimated error and capable of rejecting spatially periodic disturbances under varying system speeds. Stability proof of the overall system is given. A design example with simulation demonstrates the applicability of the proposed design.

  8. Human subjects concerns in ground based ECLSS testing - Managing uncertainty in closely recycled systems

    Science.gov (United States)

    Crump, William J.; Janik, Daniel S.; Thomas, L. Dale

    1990-01-01

    U.S. space missions have to this point used water either made on board or carried from earth and discarded after use. For Space Station Freedom, long duration life support will include air and water recycling using a series of physical-chemical subsystems. The Environmental Control and Life Support System (ECLSS) designed for this application must be tested extensively at all stages of hardware maturity. Human test subjects are required to conduct some of these tests, and the risks associated with the use of development hardware must be addressed. Federal guidelines for protection of human subjects require careful consideration of risks and potential benefits by an Institutional Review Board (IRB) before and during testing. This paper reviews the ethical principles guiding this consideration, details the problems and uncertainties inherent in current hardware testing, and presents an incremental approach to risk assessment for ECLSS testing.

  9. Hanford Environmental Information System (HEIS). Volume 7: Sample and Data Tracking subject area

    International Nuclear Information System (INIS)

    1994-06-01

    The Hanford Environmental Information System (HEIS) Sample and Data Tracking subject area allows insertion of tracking information into a central repository where the data is immediately available for viewing. For example, a technical coordinator is able to view the current status of a particular sampling effort, from sample collection to data package validation dates. Four major types of data comprise the Sample and Data Tracking subject area: data about the mechanisms that groups a set of samples for a particular sampling effort; data about how constituents are grouped and assigned to a sample; data about when, where, and how samples are sent to a laboratory for analysis; and data bout the status of a sample's constituent analysis requirements, i.e., whether the analysis results have been returned from the laboratory

  10. Double coupling: modeling subjectivity and asymmetric organization in social-ecological systems

    Directory of Open Access Journals (Sweden)

    David Manuel-Navarrete

    2015-09-01

    Full Text Available Social-ecological organization is a multidimensional phenomenon that combines material and symbolic processes. However, the coupling between social and ecological subsystem is often conceptualized as purely material, thus reducing the symbolic dimension to its behavioral and actionable expressions. In this paper I conceptualize social-ecological systems as doubly coupled. On the one hand, material expressions of socio-cultural processes affect and are affected by ecological dynamics. On the other hand, coupled social-ecological material dynamics are concurrently coupled with subjective dynamics via coding, decoding, personal experience, and human agency. This second coupling operates across two organizationally heterogeneous dimensions: material and symbolic. Although resilience thinking builds on the recognition of organizational asymmetry between living and nonliving systems, it has overlooked the equivalent asymmetry between ecological and socio-cultural subsystems. Three guiding concepts are proposed to formalize double coupling. The first one, social-ecological asymmetry, expands on past seminal work on ecological self-organization to incorporate reflexivity and subjectivity in social-ecological modeling. Organizational asymmetry is based in the distinction between social rules, which are symbolically produced and changed through human agents' reflexivity and purpose, and biophysical rules, which are determined by functional relations between ecological components. The second guiding concept, conscious power, brings to the fore human agents' distinctive capacity to produce our own subjective identity and the consequences of this capacity for social-ecological organization. The third concept, congruence between subjective and objective dynamics, redefines sustainability as contingent on congruent relations between material and symbolic processes. Social-ecological theories and analyses based on these three guiding concepts would support the

  11. Types of adaptation of the system of enterprise economic security to the impact of subjects of tax regulation

    Directory of Open Access Journals (Sweden)

    Pohorelov Yurii S.

    2014-01-01

    Full Text Available The article offers the authors’ approach to identification of types of adaptation of the system of enterprise economic security to negative influence of subjects of tax regulation. It determines composition of these subjects and, separately, regulation subjects that form fundamental grounds of the tax sphere and subjects of effective influence, which directly interact with entrepreneurial structures and realise tax regulation of their activity in practice. As regards direct adaptation of the system of enterprise economic security, the article offers to mark out its individual types with respect to the set goal, essence of changes in the system of economic security, degree of its manageability and nature of accumulated changes. Moreover, the article offers a list of catalysts and inhibitors of adaptation of the system of enterprise economic security to impact of subjects of tax regulation. It also marks out adaptation parameters of the system of enterprise economic security to the impact of subjects of tax regulation and provides their gradations.

  12. Finite-time stabilization for a class of nonholonomic feedforward systems subject to inputs saturation.

    Science.gov (United States)

    Gao, Fangzheng; Yuan, Ye; Wu, Yuqiang

    2016-09-01

    This paper studies the problem of finite-time stabilization by state feedback for a class of uncertain nonholonomic systems in feedforward-like form subject to inputs saturation. Under the weaker homogeneous condition on systems growth, a saturated finite-time control scheme is developed by exploiting the adding a power integrator method, the homogeneous domination approach and the nested saturation technique. Together with a novel switching control strategy, the designed saturated controller guarantees that the states of closed-loop system are regulated to zero in a finite time without violation of the constraint. As an application of the proposed theoretical results, the problem of saturated finite-time control for vertical wheel on rotating table is solved. Simulation results are given to demonstrate the effectiveness of the proposed method. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Finite-Time Stabilization for a Class of Nonlinear Differential-Algebraic Systems Subject to Disturbance

    Directory of Open Access Journals (Sweden)

    Xiaohui Mo

    2017-01-01

    Full Text Available In this paper, finite-time stabilization problem for a class of nonlinear differential-algebraic systems (NDASs subject to external disturbance is investigated via a composite control manner. A composite finite-time controller (CFTC is proposed with a three-stage design procedure. Firstly, based on the adding a power integrator technique, a finite-time control (FTC law is explicitly designed for the nominal NDAS by only using differential variables. Then, by using homogeneous system theory, a continuous finite-time disturbance observer (CFTDO is constructed to estimate the disturbance generated by an exogenous system. Finally, a composite controller which consists of a feedforward compensation part based on CFTDO and the obtained FTC law is proposed. Rigorous analysis demonstrates that not only the proposed composite controller can stabilize the NDAS in finite time, but also the proposed control scheme exhibits nominal performance recovery property. Simulation examples are provided to illustrate the effectiveness of the proposed control approach.

  14. Fuzzy Stabilization for Nonlinear Discrete Ship Steering Stochastic Systems Subject to State Variance and Passivity Constraints

    Directory of Open Access Journals (Sweden)

    Wen-Jer Chang

    2014-01-01

    Full Text Available For nonlinear discrete-time stochastic systems, a fuzzy controller design methodology is developed in this paper subject to state variance constraint and passivity constraint. According to fuzzy model based control technique, the nonlinear discrete-time stochastic systems considered in this paper are represented by the discrete-time Takagi-Sugeno fuzzy models with multiplicative noise. Employing Lyapunov stability theory, upper bound covariance control theory, and passivity theory, some sufficient conditions are derived to find parallel distributed compensation based fuzzy controllers. In order to solve these sufficient conditions, an iterative linear matrix inequality algorithm is applied based on the linear matrix inequality technique. Finally, the fuzzy stabilization problem for nonlinear discrete ship steering stochastic systems is investigated in the numerical example to illustrate the feasibility and validity of proposed fuzzy controller design method.

  15. Reliability analysis of multi-trigger binary systems subject to competing failures

    International Nuclear Information System (INIS)

    Wang, Chaonan; Xing, Liudong; Levitin, Gregory

    2013-01-01

    This paper suggests two combinatorial algorithms for the reliability analysis of multi-trigger binary systems subject to competing failure propagation and failure isolation effects. Propagated failure with global effect (PFGE) is referred to as a failure that not only causes outage to the component from which the failure originates, but also propagates through all other system components causing the entire system failure. However, the propagation effect from the PFGE can be isolated in systems with functional dependence (FDEP) behavior. This paper studies two distinct consequences of PFGE resulting from a competition in the time domain between the failure isolation and failure propagation effects. As compared to existing works on competing failures that are limited to systems with a single FDEP group, this paper considers more complicated cases where the systems have multiple dependent FDEP groups. Analysis of such systems is more challenging because both the occurrence order between the trigger failure event and PFGE from the dependent components and the occurrence order among the multiple trigger failure events have to be considered. Two combinatorial and analytical algorithms are proposed. Both of them have no limitation on the type of time-to-failure distributions for the system components. Their correctness is verified using a Markov-based method. An example of memory systems is analyzed to demonstrate and compare the applications and advantages of the two proposed algorithms. - Highlights: ► Reliability of binary systems with multiple dependent functional dependence groups is analyzed. ► Competing failure propagation and failure isolation effect is considered. ► The proposed algorithms are combinatorial and applicable to any arbitrary type of time-to-failure distributions for system components.

  16. Probability density function evolution of power systems subject to stochastic variation of renewable energy

    Science.gov (United States)

    Wei, J. Q.; Cong, Y. C.; Xiao, M. Q.

    2018-05-01

    As renewable energies are increasingly integrated into power systems, there is increasing interest in stochastic analysis of power systems.Better techniques should be developed to account for the uncertainty caused by penetration of renewables and consequently analyse its impacts on stochastic stability of power systems. In this paper, the Stochastic Differential Equations (SDEs) are used to represent the evolutionary behaviour of the power systems. The stationary Probability Density Function (PDF) solution to SDEs modelling power systems excited by Gaussian white noise is analysed. Subjected to such random excitation, the Joint Probability Density Function (JPDF) solution to the phase angle and angular velocity is governed by the generalized Fokker-Planck-Kolmogorov (FPK) equation. To solve this equation, the numerical method is adopted. Special measure is taken such that the generalized FPK equation is satisfied in the average sense of integration with the assumed PDF. Both weak and strong intensities of the stochastic excitations are considered in a single machine infinite bus power system. The numerical analysis has the same result as the one given by the Monte Carlo simulation. Potential studies on stochastic behaviour of multi-machine power systems with random excitations are discussed at the end.

  17. Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-Juan; FANG Mao-Fa

    2004-01-01

    From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.

  18. Interacting two-level defects as sources of fluctuating high-frequency noise in superconducting circuits

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, Clemens [ARC Centre of Excellence for Engineered Quantum Systems, The University of Queensland, Brisbane (Australia); Lisenfeld, Juergen [Physikalisches Institut, Karlsruhe Institute of Technology, Karlsruhe (Germany); Shnirman, Alexander [Institut fuer Theory der Kondensierten Materie, Karlsruhe Institute of Technology, Karlsruhe (Germany); LD Landau Institute for Theoretical Physics, Moscow (Russian Federation); Poletto, Stefano [IBM TJ Watson Research Centre, Yorktown Heights (United States)

    2016-07-01

    Since the very first experiments, superconducting circuits have suffered from strong coupling to environmental noise, destroying quantum coherence and degrading performance. In state-of-the-art experiments, it is found that the relaxation time of superconducting qubits fluctuates as a function of time. We present measurements of such fluctuations in a 3D-transmon circuit and develop a qualitative model based on interactions within a bath of background two-level systems (TLS) which emerge from defects in the device material. In our model, the time-dependent noise density acting on the qubit emerges from its near-resonant coupling to high-frequency TLS which experience energy fluctuations due to their interaction with thermally fluctuating TLS at low frequencies. We support the model by providing experimental evidence of such energy fluctuations observed in a single TLS in a phase qubit circuit.

  19. Nonlinear Jaynes–Cummings model for two interacting two-level atoms

    International Nuclear Information System (INIS)

    Santos-Sánchez, O de los; González-Gutiérrez, C; Récamier, J

    2016-01-01

    In this work we examine a nonlinear version of the Jaynes–Cummings model for two identical two-level atoms allowing for Ising-like and dipole–dipole interplays between them. The model is said to be nonlinear in the sense that it can incorporate both a general intensity-dependent interaction between the atomic system and the cavity field and/or the presence of a nonlinear medium inside the cavity. As an example, we consider a particular type of atom-field coupling based upon the so-called Buck–Sukumar model and a lossless Kerr-like cavity. We describe the possible effects of such features on the evolution of some quantities of current interest, such as atomic excitation, purity, concurrence, the entropy of the field and the evolution of the latter in phase space. (paper)

  20. Sensitivity of the appetite control system in obese subjects to nutritional and serotoninergic challenges.

    Science.gov (United States)

    Hill, A J; Blundell, J E

    1990-03-01

    The sensitivity of the appetite system of a group of obese individuals was assessed in response to two challenges known to reduce hunger and enhance satiety in lean people. The challenges were the presentation of a caloric (high protein) load and the activation of serotonin systems. Eight obese female adults (BMI = 38) received 2 X 15 mg d-fenfluramine or placebo daily for 3 days, the study conforming to a 2 X 2 factor (drug X lunch type), double blind, repeated measures design. Three hours after dosing on day 3 they ate either a high carbohydrate (63 percent of total energy) or high protein (54 percent) lunchtime meal (the caloric load). These fixed meal challenges were equal in energy (475 kcal), weight and fat content. Ratings of hunger motivation and food preferences were tracked over the course of lunch and for a further 3 hours, at which point subjects returned for a self-selection test meal. Intakes from this second open meal revealed significant main effects of both caloric load and drug on energy intake, with the high protein d-fenfluramine combination being the most potent anorectic pairing. These findings were supported by the profiles of hunger motivation. This study has confirmed that the appetite system of these subjects was responsive to these biologically relevant challenges. The results suggest that the combination of an appetite modulating drug with specific dietary intervention may represent an effective strategy for the management of hunger arising from caloric restriction.

  1. Distributed Piezoelectric Sensor System for Damage Identification in Structures Subjected to Temperature Changes.

    Science.gov (United States)

    Vitola, Jaime; Pozo, Francesc; Tibaduiza, Diego A; Anaya, Maribel

    2017-05-31

    Structural health monitoring (SHM) is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i) offering a very interesting way to acquire information from the structures under test; (ii) applying methodologies to provide a robust analysis; and (iii) performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT) sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.

  2. Distributed Piezoelectric Sensor System for Damage Identification in Structures Subjected to Temperature Changes

    Directory of Open Access Journals (Sweden)

    Jaime Vitola

    2017-05-01

    Full Text Available Structural health monitoring (SHM is a very important area in a wide spectrum of fields and engineering applications. With an SHM system, it is possible to reduce the number of non-necessary inspection tasks, the associated risk and the maintenance cost in a wide range of structures during their lifetime. One of the problems in the detection and classification of damage are the constant changes in the operational and environmental conditions. Small changes of these conditions can be considered by the SHM system as damage even though the structure is healthy. Several applications for monitoring of structures have been developed and reported in the literature, and some of them include temperature compensation techniques. In real applications, however, digital processing technologies have proven their value by: (i offering a very interesting way to acquire information from the structures under test; (ii applying methodologies to provide a robust analysis; and (iii performing a damage identification with a practical useful accuracy. This work shows the implementation of an SHM system based on the use of piezoelectric (PZT sensors for inspecting a structure subjected to temperature changes. The methodology includes the use of multivariate analysis, sensor data fusion and machine learning approaches. The methodology is tested and evaluated with aluminum and composite structures that are subjected to temperature variations. Results show that damage can be detected and classified in all of the cases in spite of the temperature changes.

  3. Experimental gingivitis induces systemic inflammatory markers in young healthy individuals: a single-subject interventional study.

    Science.gov (United States)

    Eberhard, Jörg; Grote, Karsten; Luchtefeld, Maren; Heuer, Wieland; Schuett, Harald; Divchev, Dimitar; Scherer, Ralph; Schmitz-Streit, Ruth; Langfeldt, Daniela; Stumpp, Nico; Staufenbiel, Ingmar; Schieffer, Bernhard; Stiesch, Meike

    2013-01-01

    We here investigated whether experimental gingivitis enhances systemic markers of inflammation which are also known as surrogate markers of atherosclerotic plaque development. Gingivitis is a low-level oral infection induced by bacterial deposits with a high prevalence within Western populations. A potential link between the more severe oral disease periodontitis and cardiovascular disease has already been shown. 37 non-smoking young volunteers with no inflammatory disease or any cardiovascular risk factors participated in this single-subject interventional study with an intra-individual control. Intentionally experimental oral inflammation was induced by the interruption of oral hygiene for 21 days, followed by a 21-days resolving phase after reinitiation of oral hygiene. Primary outcome measures at baseline, day 21 and 42 were concentrations of hsCRP, IL-6, and MCP-1, as well as adhesion capacity and oxLDL uptake of isolated blood monocytes. The partial cessation of oral hygiene procedures was followed by the significant increase of gingival bleeding (34.0%, Pgingivitis. Bacterial-induced gingival low-level inflammation induced a systemic increase in inflammatory markers. Dental hygiene almost completely reversed this experimental inflammatory process, suggesting that appropriate dental prophylaxis may also limit systemic markers of inflammation in subjects with natural gingivitis. International Clinical Trials Register Platform of the World Health Organization, registry number: DRKS00003366, URL: http://apps.who.int/trialsearch/Default.aspx.

  4. Bayesian feedback versus Markovian feedback in a two-level atom

    International Nuclear Information System (INIS)

    Wiseman, H.M.; Mancini, Stefano; Wang Jin

    2002-01-01

    We compare two different approaches to the control of the dynamics of a continuously monitored open quantum system. The first is Markovian feedback, as introduced in quantum optics by Wiseman and Milburn [Phys. Rev. Lett. 70, 548 (1993)]. The second is feedback based on an estimate of the system state, developed recently by Doherty and Jacobs [Phys. Rev. A 60, 2700 (1999)]. Here we choose to call it, for brevity, Bayesian feedback. For systems with nonlinear dynamics, we expect these two methods of feedback control to give markedly different results. The simplest possible nonlinear system is a driven and damped two-level atom, so we choose this as our model system. The monitoring is taken to be homodyne detection of the atomic fluorescence, and the control is by modulating the driving. The aim of the feedback in both cases is to stabilize the internal state of the atom as close as possible to an arbitrarily chosen pure state, in the presence of inefficient detection and other forms of decoherence. Our results (obtained without recourse to stochastic simulations) prove that Bayesian feedback is never inferior, and is usually superior, to Markovian feedback. However, it would be far more difficult to implement than Markovian feedback and it loses its superiority when obvious simplifying approximations are made. It is thus not clear which form of feedback would be better in the face of inevitable experimental imperfections

  5. Characterizing Psychological Dimensions in Non-Pathological Subjects through Autonomic Nervous System Dynamics

    Directory of Open Access Journals (Sweden)

    Mimma eNardelli

    2015-03-01

    Full Text Available The objective assessment of psychological traits of healthy subjects and psychiatric patients has been growing interest in clinical and bioengineering research fields during the last decade. Several experimental evidences strongly suggest that a link between Autonomic Nervous System (ANS dynamics and specific dimensions such as anxiety, social phobia, stress and emotional regulation might exist. Nevertheless, an extensive investigation on a wide range of psycho-cognitive scales and ANS non-invasive markers gathered from standard and nonlinear analysis still needs to be addressed. In this study, we analyzed the discerning and correlation capabilities of a comprehensive set of ANS features and psycho-cognitive scales in 29 non-pathological subjects monitored during resting conditions. In particular, the state of the art of standard and nonlinear analysis was performed on Heart Rate Variability, InterBreath Interval series, and Inter-Beat Respiration series, which were considered as monovariate and multivariate measurements. Experimental results show that each ANS feature is linked to specific psychological traits. Moreover, nonlinear analysis outperforms the psychological assessment with respect to standard analysis. Considering that the current clinical practice relies only on subjective scores from interviews and questionnaires, this study provides objective tools for the assessment of psychological dimensions.

  6. Stability Criterion of Linear Stochastic Systems Subject to Mixed H2/Passivity Performance

    Directory of Open Access Journals (Sweden)

    Cheung-Chieh Ku

    2015-01-01

    Full Text Available The H2 control scheme and passivity theory are applied to investigate the stability criterion of continuous-time linear stochastic system subject to mixed performance. Based on the stochastic differential equation, the stochastic behaviors can be described as multiplicative noise terms. For the considered system, the H2 control scheme is applied to deal with the problem on minimizing output energy. And the asymptotical stability of the system can be guaranteed under desired initial conditions. Besides, the passivity theory is employed to constrain the effect of external disturbance on the system. Moreover, the Itô formula and Lyapunov function are used to derive the sufficient conditions which are converted into linear matrix inequality (LMI form for applying convex optimization algorithm. Via solving the sufficient conditions, the state feedback controller can be established such that the asymptotical stability and mixed performance of the system are achieved in the mean square. Finally, the synchronous generator system is used to verify the effectiveness and applicability of the proposed design method.

  7. Supervising and Controlling Unmanned Systems: A Multi-Phase Study with Subject Matter Experts

    Science.gov (United States)

    Porat, Talya; Oron-Gilad, Tal; Rottem-Hovev, Michal; Silbiger, Jacob

    2016-01-01

    Proliferation in the use of Unmanned Aerial Systems (UASs) in civil and military operations has presented a multitude of human factors challenges; from how to bridge the gap between demand and availability of trained operators, to how to organize and present data in meaningful ways. Utilizing the Design Research Methodology (DRM), a series of closely related studies with subject matter experts (SMEs) demonstrate how the focus of research gradually shifted from “how many systems can a single operator control” to “how to distribute missions among operators and systems in an efficient way”. The first set of studies aimed to explore the modal number, i.e., how many systems can a single operator supervise and control. It was found that an experienced operator can supervise up to 15 UASs efficiently using moderate levels of automation, and control (mission and payload management) up to three systems. Once this limit was reached, a single operator's performance was compared to a team controlling the same number of systems. In general, teams led to better performances. Hence, shifting design efforts toward developing tools that support teamwork environments of multiple operators with multiple UASs (MOMU). In MOMU settings, when the tasks are similar or when areas of interest overlap, one operator seems to have an advantage over a team who needs to collaborate and coordinate. However, in all other cases, a team was advantageous over a single operator. Other findings and implications, as well as future directions for research are discussed. PMID:27252662

  8. Supervising and Controlling Unmanned Systems: A Multi-Phase Study with Subject Matter Experts.

    Science.gov (United States)

    Porat, Talya; Oron-Gilad, Tal; Rottem-Hovev, Michal; Silbiger, Jacob

    2016-01-01

    Proliferation in the use of Unmanned Aerial Systems (UASs) in civil and military operations has presented a multitude of human factors challenges; from how to bridge the gap between demand and availability of trained operators, to how to organize and present data in meaningful ways. Utilizing the Design Research Methodology (DRM), a series of closely related studies with subject matter experts (SMEs) demonstrate how the focus of research gradually shifted from "how many systems can a single operator control" to "how to distribute missions among operators and systems in an efficient way". The first set of studies aimed to explore the modal number, i.e., how many systems can a single operator supervise and control. It was found that an experienced operator can supervise up to 15 UASs efficiently using moderate levels of automation, and control (mission and payload management) up to three systems. Once this limit was reached, a single operator's performance was compared to a team controlling the same number of systems. In general, teams led to better performances. Hence, shifting design efforts toward developing tools that support teamwork environments of multiple operators with multiple UASs (MOMU). In MOMU settings, when the tasks are similar or when areas of interest overlap, one operator seems to have an advantage over a team who needs to collaborate and coordinate. However, in all other cases, a team was advantageous over a single operator. Other findings and implications, as well as future directions for research are discussed.

  9. The neutrophil-to-lymphocyte ratio as a marker of systemic endothelial dysfunction in asymptomatic subjects.

    Science.gov (United States)

    Martínez-Urbistondo, Diego; Beltrán, Almudena; Beloqui, Oscar; Huerta, Ana

    2016-01-01

    The neutrophil-to-lymphocyte ratio has demonstrated to be a prognostic inflammatory marker in cardiovascular disease. The objective of this study is to evaluate the association between neutrophil-to-lymphocyte ratio and pathologic urinary albumin/creatinine ratio as an early marker of cardiovascular risk and systemic endothelial dysfunction, associated with microvascular disease, in asymptomatic subjects. A unicenter cross-sectional study was conducted, including 1816 asymptomatic subjects. Patients with previous cardiovascular disease, those who were treated with ACE inhibitors and/or angiotensin II receptor blockers and patients with albumin/creatinine ratio over 300mg/g were excluded. The outcome of the study was the presence of a pathologic urinary albumin/creatinine ratio. The neutrophil-to-lymphocyte ratio was significantly associated with altered urinary albumin/creatinine ratio in the univariate analysis and after adjustment for other known endothelial and cardiovascular risk factors (age, hypertension, dyslipidaemia, diabetes or altered glomerular filtration rate). Based on the sensitivity and specificity of different neutrophil-to-lymphocyte ratio thresholds, 3 risk groups were created for altered urinary albumin/creatinine ratio: low risk in those with neutrophil-to-lymphocyte ratio 3. These groups were found to have a statistically significant and independent prognostic power for altered urinary albumin/creatinine ratio in asymptomatic patients. The neutrophil-to-lymphocyte ratio appears to be a cost-efficient, non-invasive and independent potential marker of systemic endothelial dysfunction in asymptomatic subjects. Copyright © 2015 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

  10. Automated Degradation Diagnosis in Character Recognition System Subject to Camera Vibration

    Directory of Open Access Journals (Sweden)

    Chunmei Liu

    2014-01-01

    Full Text Available Degradation diagnosis plays an important role for degraded character processing, which can tell the recognition difficulty of a given degraded character. In this paper, we present a framework for automated degraded character recognition system by statistical syntactic approach using 3D primitive symbol, which is integrated by degradation diagnosis to provide accurate and reliable recognition results. Our contribution is to design the framework to build the character recognition submodels corresponding to degradation subject to camera vibration or out of focus. In each character recognition submodel, statistical syntactic approach using 3D primitive symbol is proposed to improve degraded character recognition performance. In the experiments, we show attractive experimental results, highlighting the system efficiency and recognition performance by statistical syntactic approach using 3D primitive symbol on the degraded character dataset.

  11. Fast state estimation subject to random data loss in discrete-time nonlinear stochastic systems

    Science.gov (United States)

    Mahdi Alavi, S. M.; Saif, Mehrdad

    2013-12-01

    This paper focuses on the design of the standard observer in discrete-time nonlinear stochastic systems subject to random data loss. By the assumption that the system response is incrementally bounded, two sufficient conditions are subsequently derived that guarantee exponential mean-square stability and fast convergence of the estimation error for the problem at hand. An efficient algorithm is also presented to obtain the observer gain. Finally, the proposed methodology is employed for monitoring the Continuous Stirred Tank Reactor (CSTR) via a wireless communication network. The effectiveness of the designed observer is extensively assessed by using an experimental tested-bed that has been fabricated for performance evaluation of the over wireless-network estimation techniques under realistic radio channel conditions.

  12. Dynamic response of tertiary systems in structures subjected to base excitation

    International Nuclear Information System (INIS)

    Hernried, A.G.; Kai-sing Lau

    1988-01-01

    The dynamic response of very lightweight equipment (tertiary subsystem) attached to light equipment (secondary subsystem) which in turn is attached to a heavier structure (primary subsystem) that is subjected to ground shock or earthquake excitation is investigated. Both the single-degree-of-freedom and multi-degree-of-freedom subsystem models are considered. The systems are damped as well as undamped, completely detuned (all natural frequencies of the subsystems well spaced), singly tuned (one natural frequency of each subsystem equal or close to one another), or multiply tuned (more than one natural frequency of the subsystems close to each other). Efficient techniques for the determination of the tertiary subsystem response that avoid a computationally intensive numerical integration of the combined system equations are presented. (author)

  13. Perturbation Solutions for Random Linear Structural Systems subject to Random Excitation using Stochastic Differential Equations

    DEFF Research Database (Denmark)

    Köyluoglu, H.U.; Nielsen, Søren R.K.; Cakmak, A.S.

    1994-01-01

    perturbation method using stochastic differential equations. The joint statistical moments entering the perturbation solution are determined by considering an augmented dynamic system with state variables made up of the displacement and velocity vector and their first and second derivatives with respect......The paper deals with the first and second order statistical moments of the response of linear systems with random parameters subject to random excitation modelled as white-noise multiplied by an envelope function with random parameters. The method of analysis is basically a second order...... to the random parameters of the problem. Equations for partial derivatives are obtained from the partial differentiation of the equations of motion. The zero time-lag joint statistical moment equations for the augmented state vector are derived from the Itô differential formula. General formulation is given...

  14. Nonlinear dynamic modeling of a simple flexible rotor system subjected to time-variable base motions

    Science.gov (United States)

    Chen, Liqiang; Wang, Jianjun; Han, Qinkai; Chu, Fulei

    2017-09-01

    Rotor systems carried in transportation system or under seismic excitations are considered to have a moving base. To study the dynamic behavior of flexible rotor systems subjected to time-variable base motions, a general model is developed based on finite element method and Lagrange's equation. Two groups of Euler angles are defined to describe the rotation of the rotor with respect to the base and that of the base with respect to the ground. It is found that the base rotations would cause nonlinearities in the model. To verify the proposed model, a novel test rig which could simulate the base angular-movement is designed. Dynamic experiments on a flexible rotor-bearing system with base angular motions are carried out. Based upon these, numerical simulations are conducted to further study the dynamic response of the flexible rotor under harmonic angular base motions. The effects of base angular amplitude, rotating speed and base frequency on response behaviors are discussed by means of FFT, waterfall, frequency response curve and orbits of the rotor. The FFT and waterfall plots of the disk horizontal and vertical vibrations are marked with multiplications of the base frequency and sum and difference tones of the rotating frequency and the base frequency. Their amplitudes will increase remarkably when they meet the whirling frequencies of the rotor system.

  15. Performance Evaluation on Transmission Tower-Line System with Passive Friction Dampers Subjected to Wind Excitations

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2015-01-01

    Full Text Available The vibration control and performance evaluation on a transmission-tower line system by using friction dampers subjected to wind excitations are carried out in this study. The three-dimensional finite element (FE model of a transmission tower is firstly constructed. A two-dimensional lumped mass model of a transmission tower is developed for dynamic analysis. The analytical model of transmission tower-line system is proposed by taking the dynamic interaction between the tower and the transmission lines into consideration. The mechanical model of passive friction damper is presented by involving the effects of damper axial stiffness. The equation of motion of the transmission tower-line system incorporated with the friction dampers disturbed by wind excitations is established. A real transmission tower-line system is taken as an example to examine the feasibility and reliability of the proposed control approach. An extensive parameter study is carried out to find the optimal parameters of friction damper and to assess the effects of slipping force axial stiffness and hysteresis loop on control performance. The work on an example structure indicates that the application of friction dampers with optimal parameters could significantly reduce wind-induced responses of the transmission tower-line system.

  16. A Wearable System for Gait Training in Subjects with Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Filippo Casamassima

    2014-03-01

    Full Text Available In this paper, a system for gait training and rehabilitation for Parkinson’s disease (PD patients in a daily life setting is presented. It is based on a wearable architecture aimed at the provision of real-time auditory feedback. Recent studies have, in fact, shown that PD patients can receive benefit from a motor therapy based on auditory cueing and feedback, as happens in traditional rehabilitation contexts with verbal instructions given by clinical operators. To this extent, a system based on a wireless body sensor network and a smartphone has been developed. The system enables real-time extraction of gait spatio-temporal features and their comparison with a patient’s reference walking parameters captured in the lab under clinical operator supervision. Feedback is returned to the user in form of vocal messages, encouraging the user to keep her/his walking behavior or to correct it. This paper describes the overall concept, the proposed usage scenario and the parameters estimated for the gait analysis. It also presents, in detail, the hardware-software architecture of the system and the evaluation of system reliability by testing it on a few subjects.

  17. Segmental and global lordosis changes with two-level axial lumbar interbody fusion and posterior instrumentation

    Science.gov (United States)

    Melgar, Miguel A; Tobler, William D; Ernst, Robert J; Raley, Thomas J; Anand, Neel; Miller, Larry E; Nasca, Richard J

    2014-01-01

    Background Loss of lumbar lordosis has been reported after lumbar interbody fusion surgery and may portend poor clinical and radiographic outcome. The objective of this research was to measure changes in segmental and global lumbar lordosis in patients treated with presacral axial L4-S1 interbody fusion and posterior instrumentation and to determine if these changes influenced patient outcomes. Methods We performed a retrospective, multi-center review of prospectively collected data in 58 consecutive patients with disabling lumbar pain and radiculopathy unresponsive to nonsurgical treatment who underwent L4-S1 interbody fusion with the AxiaLIF two-level system (Baxano Surgical, Raleigh NC). Main outcomes included back pain severity, Oswestry Disability Index (ODI), Odom's outcome criteria, and fusion status using flexion and extension radiographs and computed tomography scans. Segmental (L4-S1) and global (L1-S1) lumbar lordosis measurements were made using standing lateral radiographs. All patients were followed for at least 24 months (mean: 29 months, range 24-56 months). Results There was no bowel injury, vascular injury, deep infection, neurologic complication or implant failure. Mean back pain severity improved from 7.8±1.7 at baseline to 3.3±2.6 at 2 years (p lordosis, defined as a change in Cobb angle ≤ 5°, was identified in 84% of patients at L4-S1 and 81% of patients at L1-S1. Patients with loss or gain in segmental or global lordosis experienced similar 2-year outcomes versus those with less than a 5° change. Conclusions/Clinical Relevance Two-level axial interbody fusion supplemented with posterior fixation does not alter segmental or global lordosis in most patients. Patients with postoperative change in lordosis greater than 5° have similarly favorable long-term clinical outcomes and fusion rates compared to patients with less than 5° lordosis change. PMID:25694920

  18. Physiological and subjective responses in the elderly when using floor heating and air conditioning systems.

    Science.gov (United States)

    Hashiguchi, Nobuko; Tochihara, Yutaka; Ohnaka, Tadakatsu; Tsuchida, Chiaki; Otsuki, Tamio

    2004-11-01

    The purpose of this study was to investigate the effects of a floor heating and air conditioning system on thermal responses of the elderly. Eight elderly men and eight university students sat for 90 minutes in a chair under the following 3 conditions: air conditioning system (A), floor heating system (F) and no heating system (C). The air temperature of sitting head height for condition A was 25 degrees C, and the maximum difference in vertical air temperature was 4 degrees C. The air and floor temperature for condition F were 21 and 29 degrees C, respectively. The air temperature for condition C was 15 degrees C. There were no significant differences in rectal temperature and mean skin temperature between condition A and F. Systolic blood pressure of the elderly men in condition C significantly increased compared to those in condition A and F. No significant differences in systolic blood pressure between condition A and F were found. The percentage of subjects who felt comfortable under condition F was higher than that of those under condition A in both age groups, though the differences between condition F and A was not significant. Relationships between thermal comfort and peripheral (e.g., instep, calf, hand) skin temperature, and the relationship between thermal comfort and leg thermal sensation were significant for both age groups. However, the back and chest skin temperature and back thermal sensation for the elderly, in contrast to that for the young, was not significantly related to thermal comfort. These findings suggested that thermal responses and physiological strain using the floor heating system did not significantly differ from that using the air conditioning system, regardless of the subject age and despite the fact that the air temperature with the floor heating system was lower. An increase in BP for elderly was observed under the condition in which the air temperature was 15 degrees C, and it was suggested that it was necessary for the elderly

  19. Two-step values for games with two-level communication structure

    NARCIS (Netherlands)

    Béal, Silvain; Khmelnitskaya, Anna Borisovna; Solal, Philippe

    TU games with two-level communication structure, in which a two-level communication structure relates fundamentally to the given coalition structure and consists of a communication graph on the collection of the a priori unions in the coalition structure, as well as a collection of communication

  20. The tracking performance of distributed recoverable flight control systems subject to high intensity radiated fields

    Science.gov (United States)

    Wang, Rui

    It is known that high intensity radiated fields (HIRF) can produce upsets in digital electronics, and thereby degrade the performance of digital flight control systems. Such upsets, either from natural or man-made sources, can change data values on digital buses and memory and affect CPU instruction execution. HIRF environments are also known to trigger common-mode faults, affecting nearly-simultaneously multiple fault containment regions, and hence reducing the benefits of n-modular redundancy and other fault-tolerant computing techniques. Thus, it is important to develop models which describe the integration of the embedded digital system, where the control law is implemented, as well as the dynamics of the closed-loop system. In this dissertation, theoretical tools are presented to analyze the relationship between the design choices for a class of distributed recoverable computing platforms and the tracking performance degradation of a digital flight control system implemented on such a platform while operating in a HIRF environment. Specifically, a tractable hybrid performance model is developed for a digital flight control system implemented on a computing platform inspired largely by the NASA family of fault-tolerant, reconfigurable computer architectures known as SPIDER (scalable processor-independent design for enhanced reliability). The focus will be on the SPIDER implementation, which uses the computer communication system known as ROBUS-2 (reliable optical bus). A physical HIRF experiment was conducted at the NASA Langley Research Center in order to validate the theoretical tracking performance degradation predictions for a distributed Boeing 747 flight control system subject to a HIRF environment. An extrapolation of these results for scenarios that could not be physically tested is also presented.

  1. Domain decomposition method of stochastic PDEs: a two-level scalable preconditioner

    International Nuclear Information System (INIS)

    Subber, Waad; Sarkar, Abhijit

    2012-01-01

    For uncertainty quantification in many practical engineering problems, the stochastic finite element method (SFEM) may be computationally challenging. In SFEM, the size of the algebraic linear system grows rapidly with the spatial mesh resolution and the order of the stochastic dimension. In this paper, we describe a non-overlapping domain decomposition method, namely the iterative substructuring method to tackle the large-scale linear system arising in the SFEM. The SFEM is based on domain decomposition in the geometric space and a polynomial chaos expansion in the probabilistic space. In particular, a two-level scalable preconditioner is proposed for the iterative solver of the interface problem for the stochastic systems. The preconditioner is equipped with a coarse problem which globally connects the subdomains both in the geometric and probabilistic spaces via their corner nodes. This coarse problem propagates the information quickly across the subdomains leading to a scalable preconditioner. For numerical illustrations, a two-dimensional stochastic elliptic partial differential equation (SPDE) with spatially varying non-Gaussian random coefficients is considered. The numerical scalability of the the preconditioner is investigated with respect to the mesh size, subdomain size, fixed problem size per subdomain and order of polynomial chaos expansion. The numerical experiments are performed on a Linux cluster using MPI and PETSc parallel libraries.

  2. Temperature measurement and control system for transtibial prostheses: Single subject clinical evaluation.

    Science.gov (United States)

    Ghoseiri, Kamiar; Zheng, Yong Ping; Leung, Aaron K L; Rahgozar, Mehdi; Aminian, Gholamreza; Masoumi, Mehdi; Safari, Mohammad Reza

    2018-01-01

    The snug fit of a prosthetic socket over the residual limb can disturb thermal balance and put skin integrity in jeopardy by providing an unpleasant and infectious environment. The prototype of a temperature measurement and control (TM&C) system was previously introduced to resolve thermal problems related to prostheses. This study evaluates its clinical application in a setting with reversal, single subject design. The TM&C system was installed on a fabricated prosthetic socket of a man with unilateral transtibial amputation. Skin temperature of the residual limb without prosthesis at baseline and with prosthesis during rest and walking was evaluated. The thermal sense and thermal comfort of the participant were also evaluated. The results showed different skin temperature around the residual limb with a temperature decrease tendency from proximal to distal. The TM&C system decreased skin temperature rise after prosthesis wearing. The same situation occurred during walking, but the thermal power of the TM&C system was insufficient to overcome heat build-up in some regions of the residual limb. The participant reported no significant change of thermal sense and thermal comfort. Further investigations are warranted to examine thermography pattern of the residual limb, thermal sense, and thermal comfort in people with amputation.

  3. Simultaneous Event-Triggered Fault Detection and Estimation for Stochastic Systems Subject to Deception Attacks.

    Science.gov (United States)

    Li, Yunji; Wu, QingE; Peng, Li

    2018-01-23

    In this paper, a synthesized design of fault-detection filter and fault estimator is considered for a class of discrete-time stochastic systems in the framework of event-triggered transmission scheme subject to unknown disturbances and deception attacks. A random variable obeying the Bernoulli distribution is employed to characterize the phenomena of the randomly occurring deception attacks. To achieve a fault-detection residual is only sensitive to faults while robust to disturbances, a coordinate transformation approach is exploited. This approach can transform the considered system into two subsystems and the unknown disturbances are removed from one of the subsystems. The gain of fault-detection filter is derived by minimizing an upper bound of filter error covariance. Meanwhile, system faults can be reconstructed by the remote fault estimator. An recursive approach is developed to obtain fault estimator gains as well as guarantee the fault estimator performance. Furthermore, the corresponding event-triggered sensor data transmission scheme is also presented for improving working-life of the wireless sensor node when measurement information are aperiodically transmitted. Finally, a scaled version of an industrial system consisting of local PC, remote estimator and wireless sensor node is used to experimentally evaluate the proposed theoretical results. In particular, a novel fault-alarming strategy is proposed so that the real-time capacity of fault-detection is guaranteed when the event condition is triggered.

  4. Stability and performance analysis of a jump linear control system subject to digital upsets

    Science.gov (United States)

    Wang, Rui; Sun, Hui; Ma, Zhen-Yang

    2015-04-01

    This paper focuses on the methodology analysis for the stability and the corresponding tracking performance of a closed-loop digital jump linear control system with a stochastic switching signal. The method is applied to a flight control system. A distributed recoverable platform is implemented on the flight control system and subject to independent digital upsets. The upset processes are used to stimulate electromagnetic environments. Specifically, the paper presents the scenarios that the upset process is directly injected into the distributed flight control system, which is modeled by independent Markov upset processes and independent and identically distributed (IID) processes. A theoretical performance analysis and simulation modelling are both presented in detail for a more complete independent digital upset injection. The specific examples are proposed to verify the methodology of tracking performance analysis. The general analyses for different configurations are also proposed. Comparisons among different configurations are conducted to demonstrate the availability and the characteristics of the design. Project supported by the Young Scientists Fund of the National Natural Science Foundation of China (Grant No. 61403395), the Natural Science Foundation of Tianjin, China (Grant No. 13JCYBJC39000), the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry, China, the Tianjin Key Laboratory of Civil Aircraft Airworthiness and Maintenance in Civil Aviation of China (Grant No. 104003020106), and the Fund for Scholars of Civil Aviation University of China (Grant No. 2012QD21x).

  5. Evaluation of Subjective and Objective Performance Metrics for Haptically Controlled Robotic Systems

    Directory of Open Access Journals (Sweden)

    Cong Dung Pham

    2014-07-01

    Full Text Available This paper studies in detail how different evaluation methods perform when it comes to describing the performance of haptically controlled mobile manipulators. Particularly, we investigate how well subjective metrics perform compared to objective metrics. To find the best metrics to describe the performance of a control scheme is challenging when human operators are involved; how the user perceives the performance of the controller does not necessarily correspond to the directly measurable metrics normally used in controller evaluation. It is therefore important to study whether there is any correspondence between how the user perceives the performance of a controller, and how it performs in terms of directly measurable metrics such as the time used to perform a task, number of errors, accuracy, and so on. To perform these tests we choose a system that consists of a mobile manipulator that is controlled by an operator through a haptic device. This is a good system for studying different performance metrics as the performance can be determined by subjective metrics based on feedback from the users, and also as objective and directly measurable metrics. The system consists of a robotic arm which provides for interaction and manipulation, which is mounted on a mobile base which extends the workspace of the arm. The operator thus needs to perform both interaction and locomotion using a single haptic device. While the position of the on-board camera is determined by the base motion, the principal control objective is the motion of the manipulator arm. This calls for intelligent control allocation between the base and the manipulator arm in order to obtain intuitive control of both the camera and the arm. We implement three different approaches to the control allocation problem, i.e., whether the vehicle or manipulator arm actuation is applied to generate the desired motion. The performance of the different control schemes is evaluated, and our

  6. Output feedback control of linear fractional transformation systems subject to actuator saturation

    Science.gov (United States)

    Ban, Xiaojun; Wu, Fen

    2016-11-01

    In this paper, the control problem for a class of linear parameter varying (LPV) plant subject to actuator saturation is investigated. For the saturated LPV plant depending on the scheduling parameters in linear fractional transformation (LFT) fashion, a gain-scheduled output feedback controller in the LFT form is designed to guarantee the stability of the closed-loop LPV system and provide optimised disturbance/error attenuation performance. By using the congruent transformation, the synthesis condition is formulated as a convex optimisation problem in terms of a finite number of LMIs for which efficient optimisation techniques are available. The nonlinear inverted pendulum problem is employed to demonstrate the effectiveness of the proposed approach. Moreover, the comparison between our LPV saturated approach with an existing linear saturated method reveals the advantage of the LPV controller when handling nonlinear plants.

  7. A feedback control system for vibration of magnetostrictive plate subjected to follower force using sinusoidal shear

    Directory of Open Access Journals (Sweden)

    A. Ghorbanpour Arani

    2016-03-01

    Full Text Available In this research, the vibrational behavior of magnetostrictive plate (MsP as a smart component is studied. The plate is subjected to an external follower force and a magnetic field in which the vibration response of MsP has been investigated for both loading combinations. The velocity feedback gain parameter is evaluated to study the effect of magnetic field which is generated by the coil. Sinusoidal shear deformation theory is utilized due to its accuracy of polynomial function with respect to other plate theories. Equations of motion are derived using Hamilton’s principle and solved by differential quadrature method (DQM considering general boundary conditions. The effects of aspect ratio, thickness ratio, follower force and velocity feedback gain are investigated on the frequency response of MsP. Results indicate that magneto-mechanical coupling in MsM helps to control vibrational behaviors of systems such as electro-hydraulic actuator, wireless linear Motors and sensors.

  8. Physical and subjective evaluation of a three-detector (TRIAD 88) SPECT system

    International Nuclear Information System (INIS)

    D'Souza, M.F.; Mumma, C.G.; Allen, E.W.; Phal, J.J.; Prince, J.R.

    1995-01-01

    The three-detector TRIAD 88 is a variable cylindrical FOV whole-body SPECT system designed for both brain as well as body organ imaging. The system performance was assessed in terms of physical indices and clinical quality. Measures of low contrast resolution using contrast-detail curves, high contrast resolution using LSFs and associated frequency descriptors, display characteristics, system sensitivity, energy resolution and uniformity analysis were utilized. In addition, images of Carlson phantom, Hoffman brain phantom and clinical brain images were used to compare two collimators subjectively. Measurements and calculations were obtained for two sets of parallel hole collimators, i.e., LEUR P AR and LEHR P AR. Of special interest is the consistency among the three detectors. The planar and volume sensitivities for the LEUR P AR collimator were about 58% of those of the LEHR P AR collimator. The planar spatial resolution of the two collimators differed by about 14%. The display was characterized by a logistic model H and D curve. The planar contrast-detail curves demonstrated no statistical difference in lesion detectability between the two collimator types, however SPECT phantom and clinical images demonstrated improved performance with the LEUR P AR collimator. Images of Hoffman single slice brain and Carlson phantoms and Tc-99m (HMPAO) brain images demonstrated excellent image quality. There was similarity in performance parameters of the three detector heads. 49 refs., 6 tabs., 8 figs

  9. The study of surgical image quality evaluation system by subjective quality factor method

    Science.gov (United States)

    Zhang, Jian J.; Xuan, Jason R.; Yang, Xirong; Yu, Honggang; Koullick, Edouard

    2016-03-01

    GreenLightTM procedure is an effective and economical way of treatment of benign prostate hyperplasia (BPH); there are almost a million of patients treated with GreenLightTM worldwide. During the surgical procedure, the surgeon or physician will rely on the monitoring video system to survey and confirm the surgical progress. There are a few obstructions that could greatly affect the image quality of the monitoring video, like laser glare by the tissue and body fluid, air bubbles and debris generated by tissue evaporation, and bleeding, just to name a few. In order to improve the physician's visual experience of a laser surgical procedure, the system performance parameter related to image quality needs to be well defined. However, since image quality is the integrated set of perceptions of the overall degree of excellence of an image, or in other words, image quality is the perceptually weighted combination of significant attributes (contrast, graininess …) of an image when considered in its marketplace or application, there is no standard definition on overall image or video quality especially for the no-reference case (without a standard chart as reference). In this study, Subjective Quality Factor (SQF) and acutance are used for no-reference image quality evaluation. Basic image quality parameters, like sharpness, color accuracy, size of obstruction and transmission of obstruction, are used as subparameter to define the rating scale for image quality evaluation or comparison. Sample image groups were evaluated by human observers according to the rating scale. Surveys of physician groups were also conducted with lab generated sample videos. The study shows that human subjective perception is a trustworthy way of image quality evaluation. More systematic investigation on the relationship between video quality and image quality of each frame will be conducted as a future study.

  10. Generalized Heine–Stieltjes and Van Vleck polynomials associated with two-level, integrable BCS models

    International Nuclear Information System (INIS)

    Marquette, Ian; Links, Jon

    2012-01-01

    We study the Bethe ansatz/ordinary differential equation (BA/ODE) correspondence for Bethe ansatz equations that belong to a certain class of coupled, nonlinear, algebraic equations. Through this approach we numerically obtain the generalized Heine–Stieltjes and Van Vleck polynomials in the degenerate, two-level limit for four cases of integrable Bardeen–Cooper–Schrieffer (BCS) pairing models. These are the s-wave pairing model, the p + ip-wave pairing model, the p + ip pairing model coupled to a bosonic molecular pair degree of freedom, and a newly introduced extended d + id-wave pairing model with additional interactions. The zeros of the generalized Heine–Stieltjes polynomials provide solutions of the corresponding Bethe ansatz equations. We compare the roots of the ground states with curves obtained from the solution of a singular integral equation approximation, which allows for a characterization of ground-state phases in these systems. Our techniques also permit the computation of the roots of the excited states. These results illustrate how the BA/ODE correspondence can be used to provide new numerical methods to study a variety of integrable systems. (paper)

  11. SPONGY (SPam ONtoloGY: Email Classification Using Two-Level Dynamic Ontology

    Directory of Open Access Journals (Sweden)

    Seongwook Youn

    2014-01-01

    Full Text Available Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user’s background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1 to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2 to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance.

  12. SPONGY (SPam ONtoloGY): email classification using two-level dynamic ontology.

    Science.gov (United States)

    Youn, Seongwook

    2014-01-01

    Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user's background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1) to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2) to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance.

  13. Testing a Quantum Heat Pump with a Two-Level Spin

    Directory of Open Access Journals (Sweden)

    Luis A. Correa

    2016-04-01

    Full Text Available Once in its non-equilibrium steady state, a nanoscale system coupled to several heat baths may be thought of as a “quantum heat pump”. Depending on the direction of its stationary heat flows, it may function as, e.g., a refrigerator or a heat transformer. These continuous heat devices can be arbitrarily complex multipartite systems, and yet, their working principle is always the same: they are made up of several elementary three-level stages operating in parallel. As a result, it is possible to devise external “black-box” testing strategies to learn about their functionality and performance regardless of any internal details. In particular, one such heat pump can be tested by coupling a two-level spin to one of its “contact transitions”. The steady state of this external probe contains information about the presence of heat leaks and internal dissipation in the device and, also, about the direction of its steady-state heat currents. Provided that the irreversibility of the heat pump is low, one can further estimate its coefficient of performance. These techniques may find applications in the emerging field of quantum thermal engineering, as they facilitate the diagnosis and design optimization of complex thermodynamic cycles.

  14. SPONGY (SPam ONtoloGY): Email Classification Using Two-Level Dynamic Ontology

    Science.gov (United States)

    2014-01-01

    Email is one of common communication methods between people on the Internet. However, the increase of email misuse/abuse has resulted in an increasing volume of spam emails over recent years. An experimental system has been designed and implemented with the hypothesis that this method would outperform existing techniques, and the experimental results showed that indeed the proposed ontology-based approach improves spam filtering accuracy significantly. In this paper, two levels of ontology spam filters were implemented: a first level global ontology filter and a second level user-customized ontology filter. The use of the global ontology filter showed about 91% of spam filtered, which is comparable with other methods. The user-customized ontology filter was created based on the specific user's background as well as the filtering mechanism used in the global ontology filter creation. The main contributions of the paper are (1) to introduce an ontology-based multilevel filtering technique that uses both a global ontology and an individual filter for each user to increase spam filtering accuracy and (2) to create a spam filter in the form of ontology, which is user-customized, scalable, and modularized, so that it can be embedded to many other systems for better performance. PMID:25254240

  15. Loading forces in shallow water running in two levels of immersion.

    Science.gov (United States)

    Haupenthal, Alessandro; Ruschel, Caroline; Hubert, Marcel; de Brito Fontana, Heiliane; Roesler, Helio

    2010-07-01

    To analyse the vertical and anteroposterior components of the ground reaction force during shallow water running at 2 levels of immersion. Twenty-two healthy adults with no gait disorders, who were familiar with aquatic exercises. Subjects performed 6 trials of water running at a self-selected speed in chest and hip immersion. Force data were collected through an underwater force plate and running speed was measured with a photocell timing light system. Analysis of covariance was used for data analysis. Vertical forces corresponded to 0.80 and 0.98 times the subject's body weight at the chest and hip level, respectively. Anteroposterior forces corresponded to 0.26 and 0.31 times the subject's body weight at the chest and hip level, respectively. As the water level decreased the subjects ran faster. No significant differences were found for the force values between the immersions, probably due to variability in speed, which was self-selected. When thinking about load values in water running professionals should consider not only the immersion level, but also the speed, as it can affect the force components, mainly the anteroposterior one. Quantitative data on this subject could help professionals to conduct safer aqua-tic rehabilitation and physical conditioning protocols.

  16. Optimal Service Distribution in WSN Service System Subject to Data Security Constraints

    Science.gov (United States)

    Wu, Zhao; Xiong, Naixue; Huang, Yannong; Gu, Qiong

    2014-01-01

    Services composition technology provides a flexible approach to building Wireless Sensor Network (WSN) Service Applications (WSA) in a service oriented tasking system for WSN. Maintaining the data security of WSA is one of the most important goals in sensor network research. In this paper, we consider a WSN service oriented tasking system in which the WSN Services Broker (WSB), as the resource management center, can map the service request from user into a set of atom-services (AS) and send them to some independent sensor nodes (SN) for parallel execution. The distribution of ASs among these SNs affects the data security as well as the reliability and performance of WSA because these SNs can be of different and independent specifications. By the optimal service partition into the ASs and their distribution among SNs, the WSB can provide the maximum possible service reliability and/or expected performance subject to data security constraints. This paper proposes an algorithm of optimal service partition and distribution based on the universal generating function (UGF) and the genetic algorithm (GA) approach. The experimental analysis is presented to demonstrate the feasibility of the suggested algorithm. PMID:25093346

  17. Two levels ARIMAX and regression models for forecasting time series data with calendar variation effects

    Science.gov (United States)

    Suhartono, Lee, Muhammad Hisyam; Prastyo, Dedy Dwi

    2015-12-01

    The aim of this research is to develop a calendar variation model for forecasting retail sales data with the Eid ul-Fitr effect. The proposed model is based on two methods, namely two levels ARIMAX and regression methods. Two levels ARIMAX and regression models are built by using ARIMAX for the first level and regression for the second level. Monthly men's jeans and women's trousers sales in a retail company for the period January 2002 to September 2009 are used as case study. In general, two levels of calendar variation model yields two models, namely the first model to reconstruct the sales pattern that already occurred, and the second model to forecast the effect of increasing sales due to Eid ul-Fitr that affected sales at the same and the previous months. The results show that the proposed two level calendar variation model based on ARIMAX and regression methods yields better forecast compared to the seasonal ARIMA model and Neural Networks.

  18. Efficiency analysis on a two-level three-phase quasi-soft-switching inverter

    DEFF Research Database (Denmark)

    Geng, Pan; Wu, Weimin; Huang, Min

    2013-01-01

    When designing an inverter, an engineer often needs to select and predict the efficiency beforehand. For the standard inverters, plenty of researches are analyzing the power losses and also many software tools are being used for efficiency calculation. In this paper, the efficiency calculation...... for non-conventional inverters with special shoot-through state is introduced and illustrated through the analysis on a special two-level three-phase quasi-soft-switching inverter. Efficiency comparison between the classical two-stage two-level three-phase inverter and the two-level three-phase quasi......-soft-switching inverter is carried out. A 10 kW/380 V prototype is constructed to verify the analysis. The experimental results show that the efficiency of the new inverter is higher than that of the traditional two-stage two- level three-phase inverter....

  19. SYSTEM OF PSYCHOLOGICAL PREVENTION AND ASSISTANCE TO THE SUBJECTS WITH THE EMOTIONAL BURNOUT SYNDROME

    Directory of Open Access Journals (Sweden)

    Надежда Ивановна Влах

    2017-10-01

    Full Text Available Subject. Consistent patterns of the genesis and phenomenology of pre-neurotic subdepressive states in emotional burnout. Objective. Elaboration and experimental verification of a methodologically and methodically substantiated system for the diagnosis and psychological assistance to the subjects with preneurotic subdepressive states in emotional burnout. Methods. The sample of the study was 968 people who appealed to Mental Health Center of Novokuznetsk of the Kemerovo Region with the complaints of a depressive nature. Psychodiagnostic methods were used as the research methods: Questionnaire of emotional burnout (V.V. Boyko, MBI Questionnaire (K. Maslach, MMPI technique (L.N. Sobchik, methodology «Emotional orientation» (B.I. Dodonov, technique of R.B. Cattell, the text of the self-description «me and my health», technique of the study of self-relationship (TSSR, the SCL-90 questionnaire, A. Langle Existence Scale. On the basis of the integration of ideographic and nomothetic approaches, the study used both low formalized and highly formalized (test methods to reflect the post-nonclassical vector of the development of contemporary psychology. Results. As the study showed, the «burnout» syndrome often appears in people with a low protective mechanism of compensation, insufficient ability to form their point of view and realistically assess the danger. Conclusions. Corrective work with the emotional burnout syndrome requires the use of various psychotherapeutic methods and the possibility of their combining both during one session and throughout the whole process of rendering psychological assistance. From a wide arsenal of individual and group psychological means the following items were chosen: situational relieving, existential counseling and Balintov groups. Preventive and rehabilitation measures were aimed at relieving stress: the removal of working tension, the increase in professional motivation.

  20. Refining Time-Activity Classification of Human Subjects Using the Global Positioning System.

    Science.gov (United States)

    Hu, Maogui; Li, Wei; Li, Lianfa; Houston, Douglas; Wu, Jun

    2016-01-01

    Detailed spatial location information is important in accurately estimating personal exposure to air pollution. Global Position System (GPS) has been widely used in tracking personal paths and activities. Previous researchers have developed time-activity classification models based on GPS data, most of them were developed for specific regions. An adaptive model for time-location classification can be widely applied to air pollution studies that use GPS to track individual level time-activity patterns. Time-activity data were collected for seven days using GPS loggers and accelerometers from thirteen adult participants from Southern California under free living conditions. We developed an automated model based on random forests to classify major time-activity patterns (i.e. indoor, outdoor-static, outdoor-walking, and in-vehicle travel). Sensitivity analysis was conducted to examine the contribution of the accelerometer data and the supplemental spatial data (i.e. roadway and tax parcel data) to the accuracy of time-activity classification. Our model was evaluated using both leave-one-fold-out and leave-one-subject-out methods. Maximum speeds in averaging time intervals of 7 and 5 minutes, and distance to primary highways with limited access were found to be the three most important variables in the classification model. Leave-one-fold-out cross-validation showed an overall accuracy of 99.71%. Sensitivities varied from 84.62% (outdoor walking) to 99.90% (indoor). Specificities varied from 96.33% (indoor) to 99.98% (outdoor static). The exclusion of accelerometer and ambient light sensor variables caused a slight loss in sensitivity for outdoor walking, but little loss in overall accuracy. However, leave-one-subject-out cross-validation showed considerable loss in sensitivity for outdoor static and outdoor walking conditions. The random forests classification model can achieve high accuracy for the four major time-activity categories. The model also performed well

  1. An EOQ Model with Stock-Dependent Demand under Two Levels of Trade Credit and Time Value of Money

    OpenAIRE

    H.A.O. Jia-Qin; M.O. Jiangtao

    2013-01-01

    Since the value of money changes with time, it is necessary to take account of the influence of time factor in making the replenishment policy. In this study, to investigate the influence of the time value of money to the inventory strategy, an inventory system for deteriorating items with stock-dependent demand is investigated under two levels of trade credit. The method to efficiently determine the optimal cycle time is presented. Numerical examples are provided to demonstrate the model and...

  2. Entanglement Criteria of Two Two-Level Atoms Interacting with Two Coupled Modes

    Science.gov (United States)

    Baghshahi, Hamid Reza; Tavassoly, Mohammad Kazem; Faghihi, Mohammad Javad

    2015-08-01

    In this paper, we study the interaction between two two-level atoms and two coupled modes of a quantized radiation field in the form of parametric frequency converter injecting within an optical cavity enclosed by a medium with Kerr nonlinearity. It is demonstrated that, by applying the Bogoliubov-Valatin canonical transformation, the introduced model is reduced to a well-known form of the generalized Jaynes-Cummings model. Then, under particular initial conditions for the atoms (in a coherent superposition of its ground and upper states) and the fields (in a standard coherent state) which may be prepared, the time evolution of state vector of the entire system is analytically evaluated. In order to understand the degree of entanglement between subsystems (atom-field and atom-atom), the dynamics of entanglement through different measures, namely, von Neumann reduced entropy, concurrence and negativity is evaluated. In each case, the effects of Kerr nonlinearity and detuning parameter on the above measures are numerically analyzed, in detail. It is illustrated that the amount of entanglement can be tuned by choosing the evolved parameters, appropriately.

  3. Two-level image authentication by two-step phase-shifting interferometry and compressive sensing

    Science.gov (United States)

    Zhang, Xue; Meng, Xiangfeng; Yin, Yongkai; Yang, Xiulun; Wang, Yurong; Li, Xianye; Peng, Xiang; He, Wenqi; Dong, Guoyan; Chen, Hongyi

    2018-01-01

    A two-level image authentication method is proposed; the method is based on two-step phase-shifting interferometry, double random phase encoding, and compressive sensing (CS) theory, by which the certification image can be encoded into two interferograms. Through discrete wavelet transform (DWT), sparseness processing, Arnold transform, and data compression, two compressed signals can be generated and delivered to two different participants of the authentication system. Only the participant who possesses the first compressed signal attempts to pass the low-level authentication. The application of Orthogonal Match Pursuit CS algorithm reconstruction, inverse Arnold transform, inverse DWT, two-step phase-shifting wavefront reconstruction, and inverse Fresnel transform can result in the output of a remarkable peak in the central location of the nonlinear correlation coefficient distributions of the recovered image and the standard certification image. Then, the other participant, who possesses the second compressed signal, is authorized to carry out the high-level authentication. Therefore, both compressed signals are collected to reconstruct the original meaningful certification image with a high correlation coefficient. Theoretical analysis and numerical simulations verify the feasibility of the proposed method.

  4. Bone mineral density in subjects using central nervous system-active medications.

    Science.gov (United States)

    Kinjo, Mitsuyo; Setoguchi, Soko; Schneeweiss, Sebastian; Solomon, Daniel H

    2005-12-01

    Decreased bone mineral density defines osteoporosis according to the World Health Organization and is an important predictor of future fractures. The use of several types of central nervous system-active drugs, including benzodiazepines, anticonvulsants, antidepressants, and opioids, have all been associated with increased risk of fracture. However, it is unclear whether such an increase in risk is related to an effect of bone mineral density or to other factors, such as increased risk of falls. We sought to examine the relationship between bone mineral density and the use of benzodiazepines, anticonvulsants, antidepressants, and opioids in a representative US population-based sample. We analyzed data on adults aged 17 years and older from the Third National Health and Nutrition Examination Survey (NHANES III, 1988-1994). Total femoral bone mineral density of 7114 male and 7532 female participants was measured by dual-energy x-ray absorptiometry. Multivariable linear regression models were used to quantify the relation between central nervous system medication exposure and total femoral bone mineral density. Models controlled for relevant covariates, including age, sex, and body mass index. In linear regression models, significantly reduced bone mineral density was found in subjects taking anticonvulsants (0.92 g/cm2; 95% confidence interval [CI]: 0.89 to 0.94) and opioids (0.92 g/cm2; 95% CI: 0.88 to 0.95) compared with nonusers (0.95 g/cm2; 95% CI: 0.95 to 0.95) after adjusting for several potential confounders. The other central nervous system-active drugs--benzodiazepines or antidepressants--were not associated with significantly reduced bone mineral density. In cross-sectional analysis of NHANES III, anticonvulsants and opioids (but not benzodiazepines or antidepressants) were associated with significantly reduced bone mineral density. These findings have implications for fracture-prevention strategies.

  5. Experimental study including subjective evaluations of mixing and displacement ventilation combined with radiant floor heating/cooling system

    DEFF Research Database (Denmark)

    Krajcik, Michal; Tomasi, Roberta; Simone, Angela

    2013-01-01

    Sixteen subjects evaluated the indoor environment in four experiments with different combinations of ventilation systems and radiant heating/cooling systems. In the first two tests, the simulated residential room was equipped either by a mixing ventilation system supplying warm air for space heat...

  6. An operational system for subject switching between controlled vocabularies: A computational linguistics approach

    Science.gov (United States)

    Silvester, J. P.; Newton, R.; Klingbiel, P. H.

    1984-01-01

    The NASA Lexical Dictionary (NLD), a system that automatically translates input subject terms to those of NASA, was developed in four phases. Phase One provided Phrase Matching, a context sensitive word-matching process that matches input phrase words with any NASA Thesaurus posting (i.e., index) term or Use reference. Other Use references have been added to enable the matching of synonyms, variant spellings, and some words with the same root. Phase Two provided the capability of translating any individual DTIC term to one or more NASA terms having the same meaning. Phase Three provided NASA terms having equivalent concepts for two or more DTIC terms, i.e., coordinations of DTIC terms. Phase Four was concerned with indexer feedback and maintenance. Although the original NLD construction involved much manual data entry, ways were found to automate nearly all but the intellectual decision-making processes. In addition to finding improved ways to construct a lexical dictionary, applications for the NLD have been found and are being developed.

  7. Message survival and decision dynamics in a class of reactive complex systems subject to external fields

    Science.gov (United States)

    Rodriguez Lucatero, C.; Schaum, A.; Alarcon Ramos, L.; Bernal-Jaquez, R.

    2014-07-01

    In this study, the dynamics of decisions in complex networks subject to external fields are studied within a Markov process framework using nonlinear dynamical systems theory. A mathematical discrete-time model is derived using a set of basic assumptions regarding the convincement mechanisms associated with two competing opinions. The model is analyzed with respect to the multiplicity of critical points and the stability of extinction states. Sufficient conditions for extinction are derived in terms of the convincement probabilities and the maximum eigenvalues of the associated connectivity matrices. The influences of exogenous (e.g., mass media-based) effects on decision behavior are analyzed qualitatively. The current analysis predicts: (i) the presence of fixed-point multiplicity (with a maximum number of four different fixed points), multi-stability, and sensitivity with respect to the process parameters; and (ii) the bounded but significant impact of exogenous perturbations on the decision behavior. These predictions were verified using a set of numerical simulations based on a scale-free network topology.

  8. LTP-like plasticity in the visual system and in the motor system appear related in young and healthy subjects

    Directory of Open Access Journals (Sweden)

    Stefan eKlöppel

    2015-09-01

    Full Text Available LTP-like plasticity measured by visual evoked potentials (VEP can be induced in the intact human brain by presenting checkerboard reversals. Also associated with LTP-like plasticity, around two third of participants respond to transcranial magnetic stimulation with a paired-associate stimulation (PAS protocol with a potentiation of their motor evoked potentials. LTP-like processes are also required for verbal and motor learning tasks. We compared effect sizes, responder rates and intercorrelations as well as the potential influence of attention between these four assessments in a group of 37 young and healthy volunteers. We observed a potentiation effect of the N75 and P100 VEP component which positively correlated with plasticity induced by PAS. Subjects with a better subjective alertness were more likely to show PAS and VEP potentiation. No correlation was found between the other assessments. Effect sizes and responder rates of VEP potentiation were higher compared to PAS. Our results indicate a high variability of LTP-like effects and no evidence for a system-specific nature. As a consequence, studies wishing to assess individual levels of LTP-like plasticity should employ a combination of multiple assessments.

  9. Asynchronous Two-Level Checkpointing Scheme for Large-Scale Adjoints in the Spectral-Element Solver Nek5000

    Energy Technology Data Exchange (ETDEWEB)

    Schanen, Michel; Marin, Oana; Zhang, Hong; Anitescu, Mihai

    2016-01-01

    Adjoints are an important computational tool for large-scale sensitivity evaluation, uncertainty quantification, and derivative-based optimization. An essential component of their performance is the storage/recomputation balance in which efficient checkpointing methods play a key role. We introduce a novel asynchronous two-level adjoint checkpointing scheme for multistep numerical time discretizations targeted at large-scale numerical simulations. The checkpointing scheme combines bandwidth-limited disk checkpointing and binomial memory checkpointing. Based on assumptions about the target petascale systems, which we later demonstrate to be realistic on the IBM Blue Gene/Q system Mira, we create a model of the expected performance of our checkpointing approach and validate it using the highly scalable Navier-Stokes spectralelement solver Nek5000 on small to moderate subsystems of the Mira supercomputer. In turn, this allows us to predict optimal algorithmic choices when using all of Mira. We also demonstrate that two-level checkpointing is significantly superior to single-level checkpointing when adjoining a large number of time integration steps. To our knowledge, this is the first time two-level checkpointing had been designed, implemented, tuned, and demonstrated on fluid dynamics codes at large scale of 50k+ cores.

  10. Solutions of the two-level problem in terms of biconfluent Heun functions

    Energy Technology Data Exchange (ETDEWEB)

    Ishkhanyan, Artur [Engineering Center of Armenian National Academy of Sciences, Ashtarak (Armenia)]. E-mail: artur@ec.sci.am; Suominen, Kalle-Antti [Helsinki Institute of Physics, Helsinki (Finland); Department of Applied Physics, University of Turku, Turku (Finland)

    2001-08-17

    Five four-parametric classes of quantum mechanical two-level models permitting solutions in terms of the biconfluent Heun function are derived. Three of these classes are generalizations of the well known classes of Landau-Zener, Nikitin and Crothers. It is shown that two other classes describe super- and sublinear and essentially nonlinear level crossings, as well as processes with three crossing points. In particular, these classes include two-level models where the field amplitude is constant and the detuning varies as {delta}{sub 0}t+{delta}{sub 2}t{sup 3} or {approx}t{sup 1/3}. For the essentially nonlinear cubic-crossing model, {delta}{sub t}{approx}{delta}{sub 2}t{sup 3}, the general solution of the two-level problem is shown to be expressed as series of confluent hypergeometric functions. (author)

  11. Two-Level Solutions to Exponentially Complex Problems in Glass Science

    DEFF Research Database (Denmark)

    Mauro, John C.; Smedskjær, Morten Mattrup

    Glass poses an especially challenging problem for physicists. The key to making progress in theoretical glass science is to extract the key physics governing properties of practical interest. In this spirit, we discuss several two-level solutions to exponentially complex problems in glass science....... Topological constraint theory, originally developed by J.C. Phillips, is based on a two-level description of rigid and floppy modes in a glass network and can be used to derive quantitatively accurate and analytically solvable models for a variety of macroscopic properties. The temperature dependence...... that captures both primary and secondary relaxation modes. Such a model also offers the ability to calculate the distinguishability of particles during glass transition and relaxation processes. Two-level models can also be used to capture the distribution of various network-forming species in mixed...

  12. Two-level system in spin baths: Non-adiabatic dynamics and heat transport

    Science.gov (United States)

    Segal, Dvira

    2014-04-01

    We study the non-adiabatic dynamics of a two-state subsystem in a bath of independent spins using the non-interacting blip approximation, and derive an exact analytic expression for the relevant memory kernel. We show that in the thermodynamic limit, when the subsystem-bath coupling is diluted (uniformly) over many (infinite) degrees of freedom, our expression reduces to known results, corresponding to the harmonic bath with an effective, temperature-dependent, spectral density function. We then proceed and study the heat current characteristics in the out-of-equilibrium spin-spin-bath model, with a two-state subsystem bridging two thermal spin-baths of different temperatures. We compare the behavior of this model to the case of a spin connecting boson baths, and demonstrate pronounced qualitative differences between the two models. Specifically, we focus on the development of the thermal diode effect, and show that the spin-spin-bath model cannot support it at weak (subsystem-bath) coupling, while in the intermediate-strong coupling regime its rectifying performance outplays the spin-boson model.

  13. Two-level system in spin baths: Non-adiabatic dynamics and heat transport

    Energy Technology Data Exchange (ETDEWEB)

    Segal, Dvira [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, 80 Saint George St., Toronto, Ontario M5S 3H6 (Canada)

    2014-04-28

    We study the non-adiabatic dynamics of a two-state subsystem in a bath of independent spins using the non-interacting blip approximation, and derive an exact analytic expression for the relevant memory kernel. We show that in the thermodynamic limit, when the subsystem-bath coupling is diluted (uniformly) over many (infinite) degrees of freedom, our expression reduces to known results, corresponding to the harmonic bath with an effective, temperature-dependent, spectral density function. We then proceed and study the heat current characteristics in the out-of-equilibrium spin-spin-bath model, with a two-state subsystem bridging two thermal spin-baths of different temperatures. We compare the behavior of this model to the case of a spin connecting boson baths, and demonstrate pronounced qualitative differences between the two models. Specifically, we focus on the development of the thermal diode effect, and show that the spin-spin-bath model cannot support it at weak (subsystem-bath) coupling, while in the intermediate-strong coupling regime its rectifying performance outplays the spin-boson model.

  14. Dynamic response of the train-track-bridge system subjected to derailment impacts

    Science.gov (United States)

    Ling, Liang; Dhanasekar, Manicka; Thambiratnam, David P.

    2018-04-01

    Derailments on bridges, although not frequent, when occurs due to a complex dynamic interaction of the train-track-bridge structural system, are very severe. Furthermore, the forced vibration induced by the post-derailment impacts can toss out the derailed wagons from the bridge deck with severe consequences to the traffic underneath and the safety of the occupants of the wagons. This paper presents a study of the train-track-bridge interaction during a heavy freight train crossing a concrete box girder bridge from a normal operation to a derailed state. A numerical model that considers the bridge vibration, train-track interaction and the train post-derailment behaviour is formulated based on a coupled finite-element - multi-body dynamics (FE-MBD) theory. The model is applied to predict the post-derailment behaviour of a freight train composed of one locomotive and several wagons, as well as the dynamic response of a straight single-span simply supported bridge containing ballast track subjected to derailment impacts. For this purpose, a typical derailment scenario of a heavy freight train passing over a severe track geometry defect is introduced. The dynamic derailment behaviour of the heavy freight train and the dynamic responses of the rail bridge are illustrated through numerical examples. The results exhibit the potential for tossing out of the derailed trains from the unstable increase in the yaw angle signature and a lower rate of increase of the bridge deck bending moment compared to the increase in the static axle load of the derailed wheelset.

  15. Lambda-Based Data Processing Architecture for Two-Level Load Forecasting in Residential Buildings

    Directory of Open Access Journals (Sweden)

    Gde Dharma Nugraha

    2018-03-01

    Full Text Available Building energy management systems (BEMS have been intensively used to manage the electricity consumption of residential buildings more efficiently. However, the dynamic behavior of the occupants introduces uncertainty problems that affect the performance of the BEMS. To address this uncertainty problem, the BEMS may implement load forecasting as one of the BEMS modules. Load forecasting utilizes historical load data to compute model predictions for a specific time in the future. Recently, smart meters have been introduced to collect electricity consumption data. Smart meters not only capture aggregation data, but also individual data that is more frequently close to real-time. The processing of both smart meter data types for load forecasting can enhance the performance of the BEMS when confronted with uncertainty problems. The collection of smart meter data can be processed using a batch approach for short-term load forecasting, while the real-time smart meter data can be processed for very short-term load forecasting, which adjusts the short-term load forecasting to adapt to the dynamic behavior of the occupants. This approach requires different data processing techniques for aggregation and individual of smart meter data. In this paper, we propose Lambda-based data processing architecture to process the different types of smart meter data and implement the two-level load forecasting approach, which combines short-term and very short-term load forecasting techniques on top of our proposed data processing architecture. The proposed approach is expected to enhance the BEMS to address the uncertainty problem in order to process data in less time. Our experiment showed that the proposed approaches improved the accuracy by 7% compared to a typical BEMS with only one load forecasting technique, and had the lowest computation time when processing the smart meter data.

  16. Kir2.1 channels set two levels of resting membrane potential with inward rectification.

    Science.gov (United States)

    Chen, Kuihao; Zuo, Dongchuan; Liu, Zheng; Chen, Haijun

    2018-04-01

    Strong inward rectifier K + channels (Kir2.1) mediate background K + currents primarily responsible for maintenance of resting membrane potential. Multiple types of cells exhibit two levels of resting membrane potential. Kir2.1 and K2P1 currents counterbalance, partially accounting for the phenomenon of human cardiomyocytes in subphysiological extracellular K + concentrations or pathological hypokalemic conditions. The mechanism of how Kir2.1 channels contribute to the two levels of resting membrane potential in different types of cells is not well understood. Here we test the hypothesis that Kir2.1 channels set two levels of resting membrane potential with inward rectification. Under hypokalemic conditions, Kir2.1 currents counterbalance HCN2 or HCN4 cation currents in CHO cells that heterologously express both channels, generating N-shaped current-voltage relationships that cross the voltage axis three times and reconstituting two levels of resting membrane potential. Blockade of HCN channels eliminated the phenomenon in K2P1-deficient Kir2.1-expressing human cardiomyocytes derived from induced pluripotent stem cells or CHO cells expressing both Kir2.1 and HCN2 channels. Weakly inward rectifier Kir4.1 or inward rectification-deficient Kir2.1•E224G mutant channels do not set such two levels of resting membrane potential when co-expressed with HCN2 channels in CHO cells or when overexpressed in human cardiomyocytes derived from induced pluripotent stem cells. These findings demonstrate a common mechanism that Kir2.1 channels set two levels of resting membrane potential with inward rectification by balancing inward currents through different cation channels such as hyperpolarization-activated HCN channels or hypokalemia-induced K2P1 leak channels.

  17. A Study on Pharmacokinetics of Bosentan with Systems Modeling, Part 2: Prospectively Predicting Systemic and Liver Exposure in Healthy Subjects.

    Science.gov (United States)

    Li, Rui; Kimoto, Emi; Niosi, Mark; Tess, David A; Lin, Jian; Tremaine, Larry M; Di, Li

    2018-04-01

    Predicting human pharmacokinetics of novel compounds is a critical step in drug discovery and clinical study design but continues to be a challenging task for hepatic transporter substrates, particularly in predicting their liver exposures. In this study, using bosentan as an example, we prospectively predicted systemic exposure and the (pseudo) steady-state unbound liver-to-unbound plasma ratio ( K p uu ) in healthy subjects using 1) a mechanistic approach solely based on in vitro hepatocyte assays and 2) an approach based on hepatic process rates from monkey in vivo data but Michaelis-Menten constants from in vitro data. Both methods reasonably match the observed human systemic time course data, but the second method leads to better prediction accuracy. In addition, the second method can predict a human K p uu value that is close to the value deduced using clinical data. We also generated rat and monkey liver K p uu values in terminal studies. However, these directly measured animal values are different from the deduced human value. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

  18. A Two-Level Cache for Distributed Information Retrieval in Search Engines

    Directory of Open Access Journals (Sweden)

    Weizhe Zhang

    2013-01-01

    Full Text Available To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users’ logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  19. A two-level cache for distributed information retrieval in search engines.

    Science.gov (United States)

    Zhang, Weizhe; He, Hui; Ye, Jianwei

    2013-01-01

    To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users' logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  20. Strong nonlinearity-induced correlations for counterpropagating photons scattering on a two-level emitter

    DEFF Research Database (Denmark)

    Nysteen, Anders; McCutcheon, Dara; Mørk, Jesper

    2015-01-01

    We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could be quanti......We analytically treat the scattering of two counterpropagating photons on a two-level emitter embedded in an optical waveguide. We find that the nonlinearity of the emitter can give rise to significant pulse-dependent directional correlations in the scattered photonic state, which could...

  1. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    Institute of Scientific and Technical Information of China (English)

    Zhang Jian; Shao Bin; Zou Jian

    2009-01-01

    In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.

  2. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    International Nuclear Information System (INIS)

    Jian, Zhang; Bin, Shao; Jian, Zou

    2009-01-01

    In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)

  3. Subjective study of thermal acceptability of novel enhanced displacement ventilation system and implication of occupants' personal control

    DEFF Research Database (Denmark)

    Sun, Weimeng; Cheong, K.W.D.; Melikov, Arsen Krikor

    2012-01-01

    with DV and constant heat load at different supply air temperatures, namely 20, 22, and 24 °C and room air temperatures, 22, 24, and 26 °C. Subjective assessments were carried out with 32 tropically-acclimatized college students who were given the choice to adjust the fan speed. Subjects' thermal comfort...... of 22 and 24 °C when the fans were in operation. It was also found that the Whole Body Thermal Sensation (WBTS) reported by the subjects was correlated with the Local Thermal Sensation (LTS) at the waist, the arms, the calf and the feet when the novel DV system was employed. An expression which allows...

  4. Experimental Research into the Two-Level Cylindrical Cyclone with a Different Number of Channels

    Directory of Open Access Journals (Sweden)

    Egidijus Baliukas

    2014-10-01

    Full Text Available The multichannel two-level cyclone has been designed for separating solid particles from airflow and built at the Laboratory of Environmental Protection Technologies of Vilnius Gediminas Technical University. The conducted research is aimed at determining air flow distribution at two levels and channels of the multichannel cyclone. The multifunctional meter Testo-400 and the dynamic Pitot tube have been used form easuring air flow rates in the channels. The obtained results show that the equal volume of air gets into two levels installed inside the cyclone, and rates are distributed equally in the channels of these levels. The maximum air flow rate is recorded in the first channel and occurs when half-rings are set in such positions so that 75% of air flow returns to the previous channel. The biggest aerodynamic resistance is 1660 Pa and has been recorded in the cyclone having eight channels under air flow distribution ratio 75/25. The highest air purification efficiency has been observed in the two-level six-channel cyclone under air flow distribution ratio 75/25. The effectiveness of separating granite particles is 92.1% and that of wood particles – 91.1 when the particles are up to 20 μm in diameter.

  5. Polynomial pseudosupersymmetry underlying a two-level atom in an external electromagnetic field

    International Nuclear Information System (INIS)

    Samsonov, B.F.; Shamshutdinova, V.V.; Gitman, D.M.

    2005-01-01

    Chains of transformations introduced previously were studied in order to obtain electric fields with a time-dependent frequency for which the equation of motion of a two-level atom in the presence of these fields can be solved exactly. It is shown that a polynomial pseudosupersymmetry may be associated to such chains

  6. Ultimate temperature for laser cooling of two-level neutral atoms

    International Nuclear Information System (INIS)

    Bagnato, V.S.; Zilio, S.C.

    1989-01-01

    We present a simple pedagogical method to evaluate the minimum attainable temperature for laser cooling of two-level neutral atoms. Results are given as a function of the laser detuning and intensity. We also discuss the use of this approach to predict the minimum temperature of neutral atoms confined in magnetic traps. (author) [pt

  7. An Owen-type value for games with two-level communication structures

    NARCIS (Netherlands)

    van den Brink, René; Khmelnitskaya, Anna Borisovna; van der Laan, Gerard

    We introduce an Owen-type value for games with two-level communication structure, which is a structure where the players are partitioned into a coalition structure such that there exists restricted communication between as well as within the a priori unions of the coalition structure. Both types of

  8. Reactive Power Impact on Lifetime Prediction of Two-level Wind Power Converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Lau, M.

    2013-01-01

    The influence of reactive power injection on the dominating two-level wind power converter is investigated and compared in terms of power loss and thermal behavior. Then the lifetime of both the partial-scale and full-scale power converter is estimated based on the widely used Coffin-Manson model...

  9. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2012-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  10. A two-level strategy to realize life-cycle production optimization in an operational setting

    NARCIS (Netherlands)

    Essen, van G.M.; Hof, Van den P.M.J.; Jansen, J.D.

    2013-01-01

    We present a two-level strategy to improve robustness against uncertainty and model errors in life-cycle flooding optimization. At the upper level, a physics-based large-scale reservoir model is used to determine optimal life-cycle injection and production profiles. At the lower level these profiles

  11. Localization of a two-level atom via the absorption spectrum

    International Nuclear Information System (INIS)

    Xu, Jun; Hu, Xiang-Ming

    2007-01-01

    We show that it is possible to localize a two-level atom as it passes through a standing-wave field by measuring the probe-field absorption. There is 50% detecting probability of the atom at the nodes of the standing-wave field in the subwavelength domain when the probe field is tuned resonant with the atomic transition

  12. Efficient two-level preconditionined conjugate gradient method on the GPU

    NARCIS (Netherlands)

    Gupta, R.; Van Gijzen, M.B.; Vuik, K.

    2011-01-01

    We present an implementation of Two-Level Preconditioned Conjugate Gradient Method for the GPU. We investigate a Truncated Neumann Series based preconditioner in combination with deflation and compare it with Block Incomplete Cholesky schemes. This combination exhibits fine-grain parallelism and

  13. A spatial scan statistic for nonisotropic two-level risk cluster.

    Science.gov (United States)

    Li, Xiao-Zhou; Wang, Jin-Feng; Yang, Wei-Zhong; Li, Zhong-Jie; Lai, Sheng-Jie

    2012-01-30

    Spatial scan statistic methods are commonly used for geographical disease surveillance and cluster detection. The standard spatial scan statistic does not model any variability in the underlying risks of subregions belonging to a detected cluster. For a multilevel risk cluster, the isotonic spatial scan statistic could model a centralized high-risk kernel in the cluster. Because variations in disease risks are anisotropic owing to different social, economical, or transport factors, the real high-risk kernel will not necessarily take the central place in a whole cluster area. We propose a spatial scan statistic for a nonisotropic two-level risk cluster, which could be used to detect a whole cluster and a noncentralized high-risk kernel within the cluster simultaneously. The performance of the three methods was evaluated through an intensive simulation study. Our proposed nonisotropic two-level method showed better power and geographical precision with two-level risk cluster scenarios, especially for a noncentralized high-risk kernel. Our proposed method is illustrated using the hand-foot-mouth disease data in Pingdu City, Shandong, China in May 2009, compared with two other methods. In this practical study, the nonisotropic two-level method is the only way to precisely detect a high-risk area in a detected whole cluster. Copyright © 2011 John Wiley & Sons, Ltd.

  14. Two-Level Designs to Estimate All Main Effects and Two-Factor Interactions

    NARCIS (Netherlands)

    Eendebak, P.T.; Schoen, E.D.

    2017-01-01

    We study the design of two-level experiments with N runs and n factors large enough to estimate the interaction model, which contains all the main effects and all the two-factor interactions. Yet, an effect hierarchy assumption suggests that main effect estimation should be given more prominence

  15. Effects of lead on the visual system of occupationally exposed subjects

    Energy Technology Data Exchange (ETDEWEB)

    Cavalleri, A.; Trimarchi, F.; Gelmi, C.; Baruffini, A.; Minoia, C.; Biscaldi, G.; Gallo, G.

    1982-01-01

    A quantitative measurement of visual field in mesopic adaptation was performed for 35 workers occupationally exposed to lead and 35 referents matched for age, smoking, and alcohol consumption. The mean level (+/- SD) of lead in blood was 47 +/- 16 microgram/100 ml (2.25 +/- 0.77 mumol/l) (range 21-82 microgram/100 ml (1.01-3.94 mumol/l)). In 10 exposed subjects a central scotoma was found that was not evidenced in any of the referents. A highly significant decrease in visual sensitivity was observed for the exposed subjects a central scotoma was found that was not evidenced in any of the referents. A highly significant decrease in visual sensitivity was observed for the exposed subjects. The results point to damage of central and peripheral optic nerve fibers. In the most severe cases, central vision is preferentially affected, and therefore the results are suggestive of subclinical optic neuropathy.

  16. [Age-related changes of sensory peripheral nerve system in healthy subjects.

    Science.gov (United States)

    Voitenkov, V B; Ekusheva, E V; Komancev, V N; Skripchenko, N V; Grigoryev, S G; Klimkin, A V; Aksenova, A I

    2017-01-01

    Our aim was to present and evaluate age-related changes of peripheral nerves of limbs on a huge population of healthy subjects of different ages. In 2009-2016 subjects aged from 1months to 90 years were studied by nerve conduction velocity studies (NCV). Data of those confirmed healthy was included in our study. In total there were 372 healthy subjects. NCV for nn. Medianus et Ulnaris was registered, with NCV and amplitude of compound sensory action potential (CSAP) being analyzed. There were significant differences on both these parameters between different age groups. Since the childhood the improvement of conduction (which was reflected in rising of CSAP amplitudes and NCV quickening) was registered; from 40-50 years steady decline of both these parameters were observed in both nerves. Conduction studies of peripheral nerves may be implemented in gerontology for early detection of neurophysiology patterns reflecting physiological aging. Also our results may be implemented for accelerated aging detection.

  17. Classification Systems for Individual Differences in Multiple-task Performance and Subjective Estimates of Workload

    Science.gov (United States)

    Damos, D. L.

    1984-01-01

    Human factors practitioners often are concerned with mental workload in multiple-task situations. Investigations of these situations have demonstrated repeatedly that individuals differ in their subjective estimates of workload. These differences may be attributed in part to individual differences in definitions of workload. However, after allowing for differences in the definition of workload, there are still unexplained individual differences in workload ratings. The relation between individual differences in multiple-task performance, subjective estimates of workload, information processing abilities, and the Type A personality trait were examined.

  18. Modelling and subject-specific validation of the heart-arterial tree system.

    Science.gov (United States)

    Guala, Andrea; Camporeale, Carlo; Tosello, Francesco; Canuto, Claudio; Ridolfi, Luca

    2015-01-01

    A modeling approach integrated with a novel subject-specific characterization is here proposed for the assessment of hemodynamic values of the arterial tree. A 1D model is adopted to characterize large-to-medium arteries, while the left ventricle, aortic valve and distal micro-circulation sectors are described by lumped submodels. A new velocity profile and a new formulation of the non-linear viscoelastic constitutive relation suitable for the {Q, A} modeling are also proposed. The model is firstly verified semi-quantitatively against literature data. A simple but effective procedure for obtaining subject-specific model characterization from non-invasive measurements is then designed. A detailed subject-specific validation against in vivo measurements from a population of six healthy young men is also performed. Several key quantities of heart dynamics-mean ejected flow, ejection fraction, and left-ventricular end-diastolic, end-systolic and stroke volumes-and the pressure waveforms (at the central, radial, brachial, femoral, and posterior tibial sites) are compared with measured data. Mean errors around 5 and 8%, obtained for the heart and arterial quantities, respectively, testify the effectiveness of the model and its subject-specific characterization.

  19. Entropy squeezing for a two-level atom in the Jaynes-Cummings model with an intensity-depend coupling

    Institute of Scientific and Technical Information of China (English)

    李春先; 方卯发

    2003-01-01

    We study the squeezing for a two-level atom in the Jaynes-Cummings model with intensity-dependent coupling using quantum information entropy, and examine the influences of the initial state of the system on the squeezed component number and direction of the information entropy squeezing. Our results show that, the squeezed component number depends on the atomic initial distribution angle, while the squeezed direction is determined by both the phases of the atom and the field for the information entropy squeezing. Quantum information entropy is shown to be a remarkable precision measure for atomic squeezing.

  20. Intraocular pressure following 18 hours of systemic dehydration in ocular normotensive healthy subjects

    Directory of Open Access Journals (Sweden)

    Faustina K. Idu

    2015-07-01

    Full Text Available Aim: To investigate the effect of dehydration on intraocular pressure (IOP. Subjects: The study population comprised 50 subjects (27 men and 23 women with a mean age of 42.84 ± 2.64 years. Method: The subjects dehydrated for 18 hours. IOP was assessed in both eyes using the Perkins handheld applanation tonometer. Baseline measurement of IOP was taken before the subjects dehydrated for 18 hours and repeated after dehydration. Blood samples were taken before and after dehydration for the determination of plasma osmolality and plasma antidiuretic hormone (ADH concentrations. Results: A statistically significant (p < 0.001 reduction in the mean weight of subjects occurred after dehydration. There was a significant reduction in IOP from 16.68 mmHg ± 0.32 mmHg to 13.08 mmHg ± 0.31 mmHg after dehydration (p < 0.001. Mean plasma osmolality showed a statistically significant increase (p < 0.05 from baseline of 290.02 mOsmol/kg ± 1.25 mOsmol/kg to 294.96 mOsmol/kg ± 1.33 mOsmol/kg after dehydration. There was also a significant increase (p < 0.05 in mean plasma ADH concentration from 5.36 pg/mL ± 0.21 pg/mL to 6.40 pg/mL ± 0.20 pg/mL after dehydration. There were no significant differences in both systolic and diastolic blood pressures before and after dehydration. Conclusion: Dehydration decreases IOP in healthy humans; this decrease probably results from an increase in plasma osmolality and plasma ADH concentrations.

  1. Analysis of renin-angiotensin aldosterone system gene polymorphisms in malaysian essential hypertensive and type 2 diabetic subjects

    Directory of Open Access Journals (Sweden)

    Stanslas Johnson

    2009-02-01

    Full Text Available Abstract Background The renin-angiotensin aldosterone system (RAAS plays an important role in regulating the blood pressure and the genetic polymorphisms of RAAS genes has been extensively studied in relation to the cardiovascular diseases in various populations with conflicting results. The aim of this study was to determine the association of five genetic polymorphisms (A6G and A20C of angiotensinogen (AGT, MboI of renin, Gly460Trp of aldosterone synthase and Lys173Arg of adducin of RAAS genes in Malaysian essential hypertensive and type 2 diabetic subjects. Methods RAAS gene polymorphisms were determined using mutagenically separated PCR and PCR-RFLP method in a total of 270 subjects consisting of 70 hypertensive subjects without type 2 diabetes mellitus (T2DM, 60 T2DM, 65 hypertensive subjects with T2DM and 75 control subjects. Results There was significant difference found in age, body mass index, systolic/diastolic blood pressure, fasting plasma glucose and high density lipoprotein cholesterol levels between the hypertensive subjects with or without T2DM and control subjects. No statistically significant differences between groups were found in the allele frequency and genotype distribution for A20C variant of AGT gene, MboI of renin, Gly460Trp of aldosterone and Lys173Arg of adducin (p > 0.05. However, the results for A6G of AGT gene revealed significant differences in allele and genotype frequencies in essential hypertension with or without T2DM (p Conclusion Among the five polymorphisms of RAAS genes only A6G variant of AGT gene was significantly associated in Malaysian essential hypertensive and type 2 diabetic subjects. Therefore, A6G polymorphism of the AGT gene could be a potential genetic marker for increased susceptibility to essential hypertension with or without T2DMin Malaysian subjects.

  2. Analysis of stationary availability factor of two-level backbone computer networks with arbitrary topology

    Science.gov (United States)

    Rahman, P. A.

    2018-05-01

    This scientific paper deals with the two-level backbone computer networks with arbitrary topology. A specialized method, offered by the author for calculation of the stationary availability factor of the two-level backbone computer networks, based on the Markov reliability models for the set of the independent repairable elements with the given failure and repair rates and the methods of the discrete mathematics, is also discussed. A specialized algorithm, offered by the author for analysis of the network connectivity, taking into account different kinds of the network equipment failures, is also observed. Finally, this paper presents an example of calculation of the stationary availability factor for the backbone computer network with the given topology.

  3. Two-Level Iteration Penalty Methods for the Navier-Stokes Equations with Friction Boundary Conditions

    Directory of Open Access Journals (Sweden)

    Yuan Li

    2013-01-01

    Full Text Available This paper presents two-level iteration penalty finite element methods to approximate the solution of the Navier-Stokes equations with friction boundary conditions. The basic idea is to solve the Navier-Stokes type variational inequality problem on a coarse mesh with mesh size H in combining with solving a Stokes, Oseen, or linearized Navier-Stokes type variational inequality problem for Stokes, Oseen, or Newton iteration on a fine mesh with mesh size h. The error estimate obtained in this paper shows that if H, h, and ε can be chosen appropriately, then these two-level iteration penalty methods are of the same convergence orders as the usual one-level iteration penalty method.

  4. A modified two-level three-phase quasi-soft-switching inverter

    DEFF Research Database (Denmark)

    Liu, Yusheng; Wu, Weimin; Blaabjerg, Frede

    2014-01-01

    A traditional Voltage Source Inverter (VSI) has higher efficiency than a Current Voltage Source (CSI) due to the less conduction power loss. However, the reverse recovery of the free-wheeling diode limits the efficiency improvement for the silicon devices based hard-switching VSI. The traditional...... quasi-soft-switching inverter can alternate between VSI and CSI by using a proper control scheme and thereby reduce the power losses caused by the reverse recovery of the free-wheeling diode. Nevertheless, slightly extra conduction power loss of the auxiliary switch is also introduced. In order...... to reduce the extra conduction power loss and the voltage stress across the DC-link capacitor, a modified two-level three-phase quasi-soft-switching inverter is proposed by using a SiC MOSFET instead of an IGBT. The principle of the modified two-level three-phase quasi-soft-switching inverter is analyzed...

  5. Revisional Surgery for Hallux Valgus with Serial Osteotomies at Two Levels

    Directory of Open Access Journals (Sweden)

    Jason B. T. Lim

    2011-01-01

    Full Text Available The aetiology and form of hallux valgus (HV is varied with many corrective procedures described. We report a 39-year-old woman, previously treated with a Chevron osteotomy, who presented with recurrent right HV, metatarsus primus varus, and associated bunion. Osteotomies were performed at two levels as a revisional procedure. This report highlights (1 limitations of the Chevron osteotomy and (2 the revisional procedure of the two level osteotomies: (i proximal opening-wedge basal osteotomy and (ii distal short Scarf with medial closing wedges. If a Chevron osteotomy is used inappropriately, for example, in an attempt to correct too large a deformity, it may angulate laterally causing a malunion with an increased distal metatarsal articular angle. Secondly, it is feasible to correct this combined deformity using a combination of proximal opening-wedge and distal short Scarf osteotomies.

  6. A Comparitive Study of Subject Knowledge of B.Ed Graduates of Formal and Non-Formal Teacher Education Systems

    Science.gov (United States)

    Saif, Perveen; Reba, Amjad; ud Din, Jalal

    2017-01-01

    This study was designed to compare the subject knowledge of B.Ed graduates of formal and non-formal teacher education systems. The population of the study included all teachers from Girls High and Higher Secondary Schools both from private and public sectors from the district of Peshawar. Out of the total population, twenty schools were randomly…

  7. Optimum design of a Lanchester damper for a viscously damped single degree of freedom system subjected to inertial excitation

    Science.gov (United States)

    Bapat, V. A.; Prabhu, P.

    1980-11-01

    The problem of designing an optimum Lanchester damper for a viscously damped single degree of freedom system subjected to inertial harmonic excitation is investigated. Two criteria are used for optimizing the performance of the damper: (i) minimum motion transmissibility; (ii) minimum force transmissibility. Explicit expressions are developed for determining the absorber parameters.

  8. Picture Exchange Communication System with Individuals with Developmental Disabilities: A Meta-Analysis of Single Subject Studies

    Science.gov (United States)

    Hart, Stephanie L.; Banda, Devender R.

    2010-01-01

    Picture Exchange Communication System (PECS) is a picture-based communication strategy used to teach communication skills to persons with developmental disabilities including autism. This article systematically reviews 13 published single-subject studies to examine the effectiveness of PECS, the effects of PECS on speech and problem behaviors,…

  9. Responses of sympathetic nervous system to cold exposure in vibration syndrome subjects and age-matched healthy controls.

    Science.gov (United States)

    Nakamoto, M

    1990-01-01

    Plasma norepinephrine and epinephrine in vibration syndrome subjects and age-matched healthy controls were measured for the purpose of estimating the responsibility of the sympathetic nervous system to cold exposure. In preliminary experiment, it was confirmed that cold air exposure of the whole body was more suitable than one-hand immersion in cold water. In the main experiment, 195 subjects were examined. Sixty-five subjects had vibration syndrome with vibration-induced white finger (VWF + group) and 65 subjects had vibration syndrome without VWF (VWF- group) and 65 controls had no symptoms (control group). In the three groups, plasma norepinephrine levels increased during cold air exposure of whole body at 7 degrees +/- 1.5 degrees C. Blood pressure increased and skin temperature decreased during cold exposure. Percent increase of norepinephrine in the VWF+ group was the highest while that in VWF- group followed and that in the control group was the lowest. This whole-body response of the sympathetic nervous system to cold conditions reflected the VWF which are characteristic symptoms of vibration syndrome. Excluding the effects of shivering and a cold feeling under cold conditions, it was confirmed that the sympathetic nervous system in vibration syndrome is activated more than in the controls. These results suggest that vibration exposure to hand and arm affects the sympathetic nervous system.

  10. Subjective Evaluation of the Microenvironment Generated by a Hospital Bed with Localized Ventilation System

    DEFF Research Database (Denmark)

    Kehayova, Nushka; Bolashikov, Zhecho Dimitrov; Melikov, Arsen Krikor

    2016-01-01

    A novel method for local hospital bed ventilation, called HBIVCU (Hospital Bed with Integrated Ventilation and Cleansing Unit), was studied in a human subject experiment. The goal of this study was to identify human response to the microenvironment generated by a hospital bed with installed HBIVC...... and the LTS acceptability votes between the two conditions could be found only for some body parts and time intervals. No draught was reported....

  11. Power quality improvement of a stand-alone power system subjected to various disturbances

    Science.gov (United States)

    Lone, Shameem Ahmad; Mufti, Mairaj Ud-Din

    In wind-diesel stand-alone power systems, the disturbances like random nature of wind power, turbulent wind, sudden changes in load demand and the wind park disconnection effect continuously the system voltage and frequency. The satisfactory operation of such a system is not an easy task and the control design has to take in to account all these subtleties. For maintaining the power quality, generally, a short-term energy storage device is used. In this paper, the performance of a wind-diesel system associated with a superconducting magnetic energy storage (SMES) system is studied. The effect of installing SMES at wind park bus/load bus, on the system performance is investigated. To control the exchange of real and reactive powers between the SMES unit and the wind-diesel system, a control strategy based on fuzzy logic is proposed. The dynamic models of the hybrid power system for most common scenarios are developed and the results presented.

  12. Urea metabolism in buffalo calves fed on rations containing two levels of crude protein

    International Nuclear Information System (INIS)

    Verma, D.N.; Singh, U.B.; Lal, M.; Varma, A.; Ranjhan, S.K.

    1974-01-01

    Urea entry rates into the body pools of Murrah Buffalo calves have been estimated using a single injection isotope dilution technique using 14 C-urea. The animals were fed two levels of crude proteins, namely, 13 percent lower and 19 percent higher than N.R.C. recommendations. Results show that the recycling of urea is significantly better in animals given low crude protein contents. (M.G.B.)

  13. FAST COMMUNICATION: A PDE Based Two Level Model of the Masking Property of the Human Ear

    OpenAIRE

    Xin, Jack; Qi, Yingyong

    2003-01-01

    Human ear has the masking property that certain audible sound becomes inaudible in the presence of another sound. Masking is quantified by the raised threshold from the absolute hearing threshold in quiet. It is of scientific and practical importance to compute masking thresholds. Empirical models on masking have applications in low bit rate digital music compression. A first principle based two level model is developed with partial differential equation (PDE) at the periphe...

  14. The off-resonant aspects of decoherence and a critique of the two-level approximation

    International Nuclear Information System (INIS)

    Savran, Kerim; Hakioglu, T; Mese, E; Sevincli, Haldun

    2006-01-01

    Conditions in favour of a realistic multilevelled description of a decohering quantum system are examined. In this regard the first crucial observation is that the thermal effects, contrary to the conventional belief, play a minor role at low temperatures in the decoherence properties. The system-environment coupling and the environmental energy spectrum dominantly affect the decoherence. In particular, zero temperature quantum fluctuations or non-equilibrium sources can be present and influential on the decoherence rates in a wide energy range allowed by the spectrum of the environment. A crucial observation against the validity of the two-level approximation is that the decoherence rates are found to be dominated not by the long time resonant but the short time off-resonant processes. This observation is demonstrated in two stages. Firstly, our zero temperature numerical results reveal that the calculated short time decoherence rates are Gaussian-like (the time dependence of the density matrix is led by the second time derivative at t = 0). Exact analytical results are also permitted in the short time limit, which, consistent with our numerical results, reveal that this specific Gaussian-like behaviour is a property of the non-Markovian correlations in the environment. These Gaussian-like rates have no dependence on any spectral parameter (position and the width of the spectrum) except, in totality, the spectral area itself. The dependence on the spectral area is a power law. Furthermore, the Gaussian-like character at short times is independent of the number of levels (N), but the numerical value of the decoherence rates is a monotonic function of N. In this context, we demonstrate that leakage, as a characteristic multilevel effect, is dominated by the non-resonant processes. The long time behaviour of decoherence is also examined. Since our spectral model allows Markovian environmental correlations at long times, the decoherence rates in this regime become

  15. Identification systems subject to plan cybersecurity; Identificacion de sistemas sujetos al plan de Ciberseguridad

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero Sanz, J.; Perez Alcaniz, T.; Garcia Garcia, I.

    2012-07-01

    The implementation of a Plan Cybersecurity ensures that systems and communications networks that perform functions related to both physical security such emergency action and their support systems, and interfaces that may affect them, are protected with an effective system against cyber attacks.

  16. 42 CFR 412.6 - Cost reporting periods subject to the prospective payment systems.

    Science.gov (United States)

    2010-10-01

    ... payment systems. 412.6 Section 412.6 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEMS FOR INPATIENT HOSPITAL SERVICES... prospective payment system for inpatient operating costs, the reasonable costs of services furnished before...

  17. 42 CFR 419.21 - Hospital outpatient services subject to the outpatient prospective payment system.

    Science.gov (United States)

    2010-10-01

    ... outpatient prospective payment system. 419.21 Section 419.21 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PROSPECTIVE PAYMENT SYSTEM... Excluded From the Hospital Outpatient Prospective Payment System § 419.21 Hospital outpatient services...

  18. Two-Level Micro-to-Nanoscale Hierarchical TiO2 Nanolayers on Titanium Surface

    Directory of Open Access Journals (Sweden)

    Elena G. Zemtsova

    2016-12-01

    Full Text Available Joint replacement is being actively developed within modern orthopedics. One novel material providing fast implantation is bioactive coatings. The synthesis of targeted nanocoatings on metallic nanotitanium surface is reported in this paper. TiO2-based micro- and nanocoatings were produced by sol-gel synthesis using dip-coating technology with subsequent fast (shock drying in hot plate mode at 400 °C. As a result of shock drying, the two-level hierarchical TiO2 nanolayer on the nanotitanium was obtained. This two-level hierarchy includes nanorelief of porous xerogel and microrelief of the micron-sized “defect” network (a crack network. The thickness of TiO2 nanolayers was controlled by repeating dip-coating process the necessary number of times after the first layer deposition. The state of the MS3T3-E1 osteoblast cell line (young cells that form bone tissue on the two-level hierarchical surface has been studied. Particularly, adhesion character, adhesion time and morphology have been studied. The reported results may serve the starting point for the development of novel bioactive coatings for bone and teeth implants.

  19. The Effects of the Disturbance of the Vestibular System on the Dynamic Balance of Idiopathic Scoliotic Subjects with and Without Exercise Therapy Compared to Healthy Subjects

    Directory of Open Access Journals (Sweden)

    N. Farahpour

    2004-01-01

    Full Text Available The mechanism of the neuromuscular system’s disorders in Adolescent Idiopathic Scoliosis (AIS are not well known. The objectives of this study were to assess the dynamic balance of the AIS patients and the influence of exercise therapy on patients' dynamic balance. Eleven teenager scoliotic subjects after three months exercise therapy, nine similar patients without therapy and 13 healthy age matched subjects as control group were studied. Using dynamic stability platform, the deviation of COG of subjects in different positions, including up right standing, standing with head flexion and standing with head hyper extension were measured. The tests were repeated in both lose and stable condition of the foot platform. Results showed that the stability of the foot platform resulted in COG's deviation by 1.13 0.08 in all subjects. Dynamic balance of scoliotic patients without treatment was similar to that of the normal subjects. While, exercised patients had less COG deviation than the other groups. The change in head position increased the COG deviation by 2.5 times in control and non-exercised patients and 1.5 times in exercised patients. The dynamic balance in scoliosis was not affected. Exercise improved the dynamic balance in scoliotic subjects. Exercise therapy is recommended to improve the proprioceptives function.

  20. Hazard rate for a two-channel protective system subject to a high demand rate

    International Nuclear Information System (INIS)

    Oliveira, L.F.; Youngblood, R.; Melo, P.F.F.

    1989-01-01

    A basic figure of merit associated with a protective system for an industrial plant is the number of accidents expected to occur in the plant within a given period of time, with the system installed. By definition, in a plant equipped with a protective system, an accident can only happen if an initiating event (a demand) occurs while the protective system is unavailable, that is, while it is in one of its possible failed states. This means that the hazard rate or accident frequency depends on the demand rate and on the unavailability of the protective systems. It has long been recognized that the demand rate influences the unavailability of the protective system, and practical expressions incorporating that effect have been developed for single-channel (Lees, 1982) and multi-channel (Kumamoto and Henley 1978) protective systems. The effect has also been incorporated into a Markovian treatment of a plant protection system (Papazoglou and Cho, 1985). In a previous paper (Oliveira and Netto, 1987) a Markovian approach was used to derive analytical expressions for the evaluation of the plant hazard rate for a single-channel protective system, properly accounting for the effects of the demand and the repair rates. In this paper the authors present an extension of that model to the case of a plant equipped with a two-channel protective system

  1. Status and subjects of thermal-hydraulic analysis for next-generation LWRs with passive safety systems

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The present status and subjects on thermal-hydraulic analysis for next-generation light water reactors (LWRs) with passive safety systems were summarized based on survey results and discussion by subcommittee on improvement of reactor thermal-hydraulic analysis codes under nuclear code committee in Japan Atomic Energy Research Institute. This survey was performed to promote the research of improvement of reactor thermal-hydraulic analysis codes in future. In the first part of this report, the status and subjects on system analysis and those on evaluation of passive safety system performance are summarized for various types of reactor proposed before. In the second part, the status and subjects on multidimensional two-phase flow analysis are reviewed, since the multidimensional analysis was recognized as one of most important subjects through the investigation in the first part. Besides, databases for bubbly flow and annular dispersed flow were explored, those are needed to assess and verify each multidimensional analytical method. The contents in this report are the forefront of thermal-hydraulic analysis for LWRs and those include current findings for the development of multidimensional two-phase flow analytical method. Thus, we expect that the contents can offer various useful information against the improvement of reactor thermal-hydraulic analysis codes in future. (author)

  2. Walking-adaptability assessments with the Interactive Walkway: Between-systems agreement and sensitivity to task and subject variations.

    Science.gov (United States)

    Geerse, Daphne J; Coolen, Bert H; Roerdink, Melvyn

    2017-05-01

    The ability to adapt walking to environmental circumstances is an important aspect of walking, yet difficult to assess. The Interactive Walkway was developed to assess walking adaptability by augmenting a multi-Kinect-v2 10-m walkway with gait-dependent visual context (stepping targets, obstacles) using real-time processed markerless full-body kinematics. In this study we determined Interactive Walkway's usability for walking-adaptability assessments in terms of between-systems agreement and sensitivity to task and subject variations. Under varying task constraints, 21 healthy subjects performed obstacle-avoidance, sudden-stops-and-starts and goal-directed-stepping tasks. Various continuous walking-adaptability outcome measures were concurrently determined with the Interactive Walkway and a gold-standard motion-registration system: available response time, obstacle-avoidance and sudden-stop margins, step length, stepping accuracy and walking speed. The same holds for dichotomous classifications of success and failure for obstacle-avoidance and sudden-stops tasks and performed short-stride versus long-stride obstacle-avoidance strategies. Continuous walking-adaptability outcome measures generally agreed well between systems (high intraclass correlation coefficients for absolute agreement, low biases and narrow limits of agreement) and were highly sensitive to task and subject variations. Success and failure ratings varied with available response times and obstacle types and agreed between systems for 85-96% of the trials while obstacle-avoidance strategies were always classified correctly. We conclude that Interactive Walkway walking-adaptability outcome measures are reliable and sensitive to task and subject variations, even in high-functioning subjects. We therefore deem Interactive Walkway walking-adaptability assessments usable for obtaining an objective and more task-specific examination of one's ability to walk, which may be feasible for both high

  3. Organizing for Instruction in Education Systems and School Organizations: "How" the Subject Matters

    Science.gov (United States)

    Spillane, James P.; Hopkins, Megan

    2013-01-01

    Teaching, the core technology of schooling, is an essential consideration in investigations of education systems and school organizations. Taking teaching seriously as an explanatory variable in research on education systems and organizations necessitates moving beyond treating it as a unitary practice, so as to take account of the school subjects…

  4. The influence of subjective norm on intention to use of learning management system among Malaysian higher education students

    Science.gov (United States)

    Baleghi-Zadeh, Sousan; Ayub, Ahmad Fauzi Mohd; Mahmud, Rosnaini; Daud, Shaffe Mohd

    2014-12-01

    In recent years, the use of learning management system by universities has been increasingly growing. However, the results of several studies have revealed that students do not fully use the information systems. The present study proposes a model which investigates the influence of three constructs of perceived ease of use, perceived usefulness, and subjective norm on behavior intention to use of learning management system. The sample size was 216 Malaysian undergraduate students. The results of the study revealed that the proposed model accounts for 31.1 % variance of behavior intention to use.

  5. Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

    Science.gov (United States)

    Jeon, Juncheol; Han, Chulhee; Chung, Jye Ung; Choi, Seung-Bok

    2015-01-01

    In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains.

  6. Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

    International Nuclear Information System (INIS)

    Jeon, Juncheol; Han, Chulhee; Ung Chung, Jye; Choi, Seung-Bok

    2015-01-01

    In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains. (paper)

  7. Energetic optimization of a solar thermochemical energy storage system subject to real constraints

    Energy Technology Data Exchange (ETDEWEB)

    Lovegrove, K [Australian National Univ., Canberra (Australia). Energy Research Centre

    1993-12-01

    An approach to the optimization of a solar energy conversion system which involves treating the system as a series of subsystems, each having a single cost determining variable, is proposed. The application to an ammonia-based thermochemical system with direct work output is discussed and possible subsystems are identified. The subsystem consisting of the exothermic reactor has been studied in detail. For this subsystem, the ratio of available catalyst volume to thermal power level is held constant whilst the exergetic efficiency is maximized. Results are presented from a determination of optimized reaction paths using dynamic programming techniques. (author)

  8. Stability analysis of direct contact heat exchangers subject to system perturbations. Final report, Task 2

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, H.R.

    1985-01-01

    This report includes a project summary, copies of two papers resulting from the work and the Ph.D. Dissertation of Dr. Mehdi Golafshani entitled, ''Stability of a Direct Contact Heat Exchanger''. Specifically, the work deals with the operational stability of a spray column type heat exchanger subject to disturbances typical of those which can occur for geothermal applications. A computer program was developed to solve the one-dimensional transient two-phase flow problem and it was applied to the design of a spray column. The operation and design of the East Mesa 500kW/sub e/ direct contactor was assessed. It is shown that the heat transfer is governed by the internal resistance of the dispersed phase. In fact, the performance is well-represented by diffusion of heat within the drops. 5 refs.

  9. The hemopoiesis system in subjects exposed as a result of the Chernobyl accident

    International Nuclear Information System (INIS)

    Bebeshko, V.G.; Klimenko, V.I.; Yukhimuk, L.N.

    1996-01-01

    The purpose of this study was to elucidate the role of cell and membrane factors in the realization of remote effects of exposure to ionizing radiation as a result of the Chernobyl power plant accident. Twenty-nine subjects exposed in doses of 0.3 to 3 Sv were examined. Seven of them has a history of acute radiation disease of the first degree, two that of the second degree, and one of the third degree. Under study were the morphology and function of blood and bone marrow elements, colony-forming activity of hemopoietic precursor cells in tissue culture in vivo, and the antioxidant function of blood plasma assessed by paramagnetic resonance from the levels of transferrin and ceruloplasmin. Refs. 9, figs. 1, tabs. 4

  10. Stochastic resonance in a bistable system subject to multi-time-delayed feedback and aperiodic signal

    International Nuclear Information System (INIS)

    Li Jianlong; Zeng Lingzao

    2010-01-01

    We discuss in detail the effects of the multi-time-delayed feedback driven by an aperiodic signal on the output of a stochastic resonance (SR) system. The effective potential function and dynamical probability density function (PDF) are derived. To measure the performance of the SR system in the presence of a binary random signal, the bit error rate (BER) defined by the dynamical PDF is employed, as is commonly used in digital communications. We find that the delay time, strength of the feedback, and number of time-delayed terms can change the effective potential function and the effective amplitude of the signal, and then affect the BER of the SR system. The numerical simulations strongly support the theoretical results. The goal of this investigation is to explore the effects of the multi-time-delayed feedback on SR and give a guidance to nonlinear systems in the application of information processing.

  11. Optimal maintenance policy for a system subject to damage in a discrete time process

    International Nuclear Information System (INIS)

    Chien, Yu-Hung; Sheu, Shey-Huei; Zhang, Zhe George

    2012-01-01

    Consider a system operating over n discrete time periods (n=1, 2, …). Each operation period causes a random amount of damage to the system which accumulates over time periods. The system fails when the cumulative damage exceeds a failure level ζ and a corrective maintenance (CM) action is immediately taken. To prevent such a failure, a preventive maintenance (PM) may be performed. In an operation period without a CM or PM, a regular maintenance (RM) is conducted at the end of that period to maintain the operation of the system. We propose a maintenance policy which prescribes a PM when the accumulated damage exceeds a pre-specified level δ ( ⁎ and N ⁎ and discuss some useful properties about them. It has been shown that a δ-based PM outperforms a N-based PM in terms of cost minimization. Numerical examples are presented to demonstrate the optimization of this class of maintenance policies.

  12. Effects of Lactobacillus acidophilus NCFM on insulin sensitivity and the systemic inflammatory response in human subjects

    DEFF Research Database (Denmark)

    Andreasen, Anne Sofie; Larsen, Nadja; Pedersen-Skovsgaard, Theis

    2010-01-01

    According to animal studies, intake of probiotic bacteria may improve glucose homeostasis. We hypothesised that probiotic bacteria improve insulin sensitivity by attenuating systemic inflammation. Therefore, the effects of oral supplementation with the probiotic bacterium Lactobacillus acidophilus...

  13. Joint cost of energy under an optimal economic policy of hybrid power systems subject to uncertainty

    International Nuclear Information System (INIS)

    Díaz, Guzmán; Planas, Estefanía; Andreu, Jon; Kortabarria, Iñigo

    2015-01-01

    Economical optimization of hybrid systems is usually performed by means of LCoE (levelized cost of energy) calculation. Previous works deal with the LCoE calculation of the whole hybrid system disregarding an important issue: the stochastic component of the system units must be jointly considered. This paper deals with this issue and proposes a new fast optimal policy that properly calculates the LCoE of a hybrid system and finds the lowest LCoE. This proposed policy also considers the implied competition among power sources when variability of gas and electricity prices are taken into account. Additionally, it presents a comparative between the LCoE of the hybrid system and its individual technologies of generation by means of a fast and robust algorithm based on vector logical computation. Numerical case analyses based on realistic data are presented that valuate the contribution of technologies in a hybrid power system to the joint LCoE. - Highlights: • We perform the LCoE calculation with the stochastic component jointly considered. • We propose a fast an optimal policy that minimizes the LCoE. • We compare the obtained LCoEs by means of a fast and robust algorithm. • We take into account the competition among gas prices and electricity prices

  14. Characteristics of the 2011 Tohoku Tsunami and introduction of two level tsunamis for tsunami disaster mitigation.

    Science.gov (United States)

    Sato, Shinji

    2015-01-01

    Characteristics of the 2011 Tohoku Tsunami have been revealed by collaborative tsunami surveys extensively performed under the coordination of the Joint Tsunami Survey Group. The complex behaviors of the mega-tsunami were characterized by the unprecedented scale and the low occurrence frequency. The limitation and the performance of tsunami countermeasures were described on the basis of tsunami surveys, laboratory experiments and numerical analyses. These findings contributed to the introduction of two-level tsunami hazards to establish a new strategy for tsunami disaster mitigation, combining structure-based flood protection designed by the Level-1 tsunami and non-structure-based damage reduction planned by the Level-2 tsunami.

  15. Teleporting the one-qubit state via two-level atoms with spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Hu Mingliang, E-mail: mingliang0301@xupt.edu.cn, E-mail: mingliang0301@163.com [School of Science, Xi' an University of Posts and Telecommunications, Xi' an 710061 (China)

    2011-05-14

    We study quantum teleportation via two two-level atoms coupled collectively to a multimode vacuum field and prepared initially in different atomic states. We concentrated on the influence of the spontaneous emission, collective damping and dipole-dipole interaction of the atoms on fidelity dynamics of quantum teleportation and obtained the region of spatial distance between the two atoms over which the state can be teleported nonclassically. Moreover, we showed through concrete examples that entanglement of the channel state is the prerequisite but not the only essential quantity for predicting the teleportation fidelity.

  16. A January angular momentum balance in the OSU two-level atmospheric general circulation model

    Science.gov (United States)

    Kim, J.-W.; Grady, W.

    1982-01-01

    The present investigation is concerned with an analysis of the atmospheric angular momentum balance, based on the simulation data of the Oregon State University two-level atmospheric general circulation model (AGCM). An attempt is also made to gain an understanding of the involved processes. Preliminary results on the angular momentum and mass balance in the AGCM are shown. The basic equations are examined, and questions of turbulent momentum transfer are investigated. The methods of analysis are discussed, taking into account time-averaged balance equations, time and longitude-averaged balance equations, mean meridional circulation, the mean meridional balance of relative angular momentum, and standing and transient components of motion.

  17. Elimination of two level fluctuators in superconducting quantum bits by an epitaxial tunnel barrier

    International Nuclear Information System (INIS)

    Oh, Seongshik; Cicak, Katarina; Kline, Jeffrey S.; Sillanpaeae, Mika A.; Osborn, Kevin D.; Whittaker, Jed D.; Simmonds, Raymond W.; Pappas, David P.

    2006-01-01

    Quantum computing based on Josephson junction technology is considered promising due to its scalable architecture. However, decoherence is a major obstacle. Here, we report evidence for improved Josephson quantum bits (qubits) using a single-crystal Al 2 O 3 tunnel barrier. We have found an ∼80% reduction in the density of the spectral splittings that indicate the existence of two-level fluctators (TLFs) in amorphous tunnel barriers. The residual ∼20% TLFs can be attributed to interfacial effects that may be further reduced by different electrode materials. These results show that decoherence sources in the tunnel barrier of Josephson qubits can be identified and eliminated

  18. Geometric manipulation of the quantum states of two-level atoms

    International Nuclear Information System (INIS)

    Tian, Mingzhen; Barber, Zeb W.; Fischer, Joe A.; Babbitt, Wm. Randall

    2004-01-01

    Manipulation of the quantum states of two-level atoms has been investigated using laser-controlled geometric phase change, which has the potential to build robust quantum logic gates for quantum computing. For a qubit based on two electronic transition levels of an atom, two basic quantum operations that can make any universal single qubit gate have been designed employing resonant laser pulses. An operation equivalent to a phase gate has been demonstrated using Tm 3+ doped in a yttrium aluminum garnet crystal

  19. Loschmidt echo of a two-level qubit coupled to nonuniform anisotropic XY chains in a transverse field

    International Nuclear Information System (INIS)

    Zhong Ming; Tong Peiqing

    2011-01-01

    The Loschmidt echo (LE) of a central two-level qubit coupled to nonuniform anisotropic XY chains in a transverse field is studied. A general formula for LE is derived, which we use to discuss the influence of the criticality of the environment on LE. It is found that for the periodic XY chain the behaviors of LE in the vicinity of the critical points are similar to those of the uniform case. It is different for the disordered transverse Ising chains. For the aperiodic chains, if the surrounding systems are bounded chains, the behaviors of LE are similar to those of the uniform case, while if the surrounding systems are unbounded chains, they are similar to those of the disordered case.

  20. An Economic Order Quantity Model with Completely Backordering and Nondecreasing Demand under Two-Level Trade Credit

    Directory of Open Access Journals (Sweden)

    Zohreh Molamohamadi

    2014-01-01

    Full Text Available In the traditional inventory system, it was implicitly assumed that the buyer pays to the seller as soon as he receives the items. In today’s competitive industry, however, the seller usually offers the buyer a delay period to settle the account of the goods. Not only the seller but also the buyer may apply trade credit as a strategic tool to stimulate his customers’ demands. This paper investigates the effects of the latter policy, two-level trade credit, on a retailer’s optimal ordering decisions within the economic order quantity framework and allowable shortages. Unlike most of the previous studies, the demand function of the customers is considered to increase with time. The objective of the retailer’s inventory model is to maximize the profit. The replenishment decisions optimally are obtained using genetic algorithm. Two special cases of the proposed model are discussed and the impacts of parameters on the decision variables are finally investigated. Numerical examples demonstrate the profitability of the developed two-level supply chain with backorder.

  1. Adaptive Backstepping-Based Neural Tracking Control for MIMO Nonlinear Switched Systems Subject to Input Delays.

    Science.gov (United States)

    Niu, Ben; Li, Lu

    2018-06-01

    This brief proposes a new neural-network (NN)-based adaptive output tracking control scheme for a class of disturbed multiple-input multiple-output uncertain nonlinear switched systems with input delays. By combining the universal approximation ability of radial basis function NNs and adaptive backstepping recursive design with an improved multiple Lyapunov function (MLF) scheme, a novel adaptive neural output tracking controller design method is presented for the switched system. The feature of the developed design is that different coordinate transformations are adopted to overcome the conservativeness caused by adopting a common coordinate transformation for all subsystems. It is shown that all the variables of the resulting closed-loop system are semiglobally uniformly ultimately bounded under a class of switching signals in the presence of MLF and that the system output can follow the desired reference signal. To demonstrate the practicability of the obtained result, an adaptive neural output tracking controller is designed for a mass-spring-damper system.

  2. On preventive maintenance policy of a critical reliability level for system subject to degradation

    International Nuclear Information System (INIS)

    Zhao, Y.X.

    2003-01-01

    Conventional preventive maintenance (PM) policies generally hold same time interval for PM actions and are often applied with known failure modes. The same time interval will give unavoidably decreasing reliabilities at the PM actions for degradation system with imperfect PM effect and the known failure modes may be inaccurate in practice. Therefore, field managers would prefer policy with an acceptable reliability level to keep system often at a good state. A PM policy with the critical reliability level is presented to address the preference of field managers. Through assuming that system after a PM action starts a new failure process, a parameter so-called degradation ratio is introduced to represent the imperfect effect. The policy holds a law that there is same number of failures in the time intervals of various PM cycles, and same degradation ratio for the system reliability or benefit parameters such as the optimal time intervals and the hazard rates between the neighboring PM cycles. This law is valid to any of the failure modes that could be appropriately referred as a 'general isodegrading model', and the degradation ratio as a 'general isodegrading ratio'. In addition, life cycle availability and cost functions are derived for system with the policy. An analysis of the field data of a loading and unloading machine indicates that the reliability, availability and cost in life cycle might be well modeled by the present theory and approach

  3. A preventive maintenance model with a two-level inspection policy based on a three-stage failure process

    International Nuclear Information System (INIS)

    Wang, Wenbin; Zhao, Fei; Peng, Rui

    2014-01-01

    Inspection is always an important preventive maintenance (PM) activity and can have different depths and cover all or part of plant systems. This paper introduces a two-level inspection policy model for a single component plant system based on a three-stage failure process. Such a failure process divides the system′s life into three stages: good, minor defective and severe defective stages. The first level of inspection, the minor inspection, can only identify the minor defective stage with a certain probability, but can always reveal the severe defective stage. The major inspection can however identify both defective stages perfectly. Once the system is found to be in the minor defective stage, a shortened inspection interval is adopted. If however the system is found to be in the severe defective stage, we may delay the maintenance action if the time to the next planned PM window is less than a threshold level, but otherwise, replace immediately. This corresponds to the well adopted maintenance policy in practice such as periodic inspections with planned PMs. A numerical example is presented to demonstrate the proposed model by comparing with other models. - Highlights: • The system′s deterioration goes through a three-stage process, namely, normal, minor defective and severe defective. • Two levels of inspections are proposed, e.g., minor and major inspections. • Once the minor defective stage is found, instead of taking a maintenance action, a shortened inspection interval is recommended. • When the severe defective stage is found, we delay the maintenance according to the threshold to the next PM. • The decision variables are the inspection intervals and the threshold to PM

  4. Systems Engineering and Safety Issues in Scientific Facilities Subject to Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Pierre Bonnal

    2013-10-01

    Full Text Available The conception and development of large-scale scientific facilities emitting ionizing radiations rely more on project management practices in use in the process industry than on systems engineering practices. This paper aims to highlight possible reasons for this present situation and to propose some ways to enhance systems engineering so that the specific radiation safety requirements are considered and integrated in the approach. To do so, we have reviewed lessons learned from the management of large-scale scientific projects and more specifically that of the Large Hadron Collider project at CERN. It is shown that project management and systems engineering practices are complementary and can beneficially be assembled in an integrated and lean managerial framework that grants the appropriate amount of focus to safety and radiation safety aspects.

  5. A shock and wear system under environmental conditions subject to internal failures, repair, and replacement

    International Nuclear Information System (INIS)

    Montoro-Cazorla, Delia; Pérez-Ocón, Rafael

    2012-01-01

    A system in a random environment is considered. The influence of the external conditions is governed by a Markovian arrival process. The internal structure of failure and repair are governed by phase-type distributions. The maintenance is performed by policy N. Under these assumptions, the Markov process governing the system is constructed, and it is studied in transient and stationary regime, calculating the availability and the rate of occurrence of failures. The renewal process due to the replacements of the system is studied, and expressions for the number of replacements and for the number of repairs between replacements are calculated. This paper extends other previously published since it incorporates a shock arrival process with dependence among the interarrival times and the renewal process associated to the replacements. A numerical application illustrates the calculations.

  6. Doubly Fed Induction Generator Wind Turbine Systems Subject to Recurring Symmetrical Grid Faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan

    2016-01-01

    New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the doubly Ffed induction generator (DFIG) wind turbine system under recurring symmetrical grid faults is analyzed. The mathematical model of the DFIG under recurring symmetrical...... grid faults is established. The analysis is based on the DFIG wind turbine system with the typical low-voltage ride-through strategy-with rotor-side crowbar. The stator natural flux produced by the voltage recovery after the first grid fault may be superposed on the stator natural flux produced...... by the second grid fault, so that the transient rotor and stator current and torque fluctuations under the second grid fault may be influenced by the characteristic of the first grid fault, including the voltage dips level and the grid fault angle, as well as the duration between two faults. The mathematical...

  7. Generalized projective chaos synchronization of gyroscope systems subjected to dead-zone nonlinear inputs

    International Nuclear Information System (INIS)

    Yau, H.-T.

    2008-01-01

    This Letter presents a robust control scheme to generalized projective synchronization between two identical two-degrees-of-freedom heavy symmetric gyroscopes with dead zone nonlinear inputs. Because of the nonlinear terms of the gyroscope system, the system exhibits complex and chaotic motions. By the Lyapunov stability theory with control terms, two suitable sliding surfaces are proposed to ensure the stability of the controlled closed-loop system in sliding mode. Then, two sliding mode controllers (SMC) are designed to guarantee the hitting of the sliding surfaces even when the control inputs contain dead-zone nonlinearity. This method allows us to arbitrarily direct the scaling factor onto a desired value. Numerical simulations show that this method works very well for the proposed controller

  8. Do subjective cognitive complaints correlate with cognitive impairment in systemic lupus erythematosus? A Danish outpatient study

    DEFF Research Database (Denmark)

    Vogel, A; Bhattacharya, S; Larsen, J L

    2011-01-01

    This study examined the prevalence of cognitive impairment and its association with depressive symptoms and self-reported cognitive complaints in Danish outpatients with systemic lupus erythematosus (SLE). Fifty-seven consecutive female SLE-outpatients were examined with a comprehensive neuropsyc......This study examined the prevalence of cognitive impairment and its association with depressive symptoms and self-reported cognitive complaints in Danish outpatients with systemic lupus erythematosus (SLE). Fifty-seven consecutive female SLE-outpatients were examined with a comprehensive...

  9. Doubly fed induction generator based wind turbine systems subject to recurring grid faults

    DEFF Research Database (Denmark)

    Chen, Wenjie; Blaabjerg, Frede; Zhu, Nan

    2014-01-01

    New grid codes demand the wind turbine systems to ride through recurring grid faults. In this paper, the performance of the Doubly Fed Induction Generator wind turbine system under recurring grid faults is analyzed. The stator natural flux produced by the voltage recovery after the first grid fault...... may be superposed on the stator natural flux produced by the second grid fault, and it may result in large current and voltage transient. The damping of the stator natural flux can be accelerated with a rotor natural current in its opposite direction after voltage recovery, but larger torque....... The performance of DFIG under recurring grid faults is verified by the simulation and experiments....

  10. Dynamical Consensus Algorithm for Second-Order Multi-Agent Systems Subjected to Communication Delay

    International Nuclear Information System (INIS)

    Liu Chenglin; Liu Fei

    2013-01-01

    To solve the dynamical consensus problem of second-order multi-agent systems with communication delay, delay-dependent compensations are added into the normal asynchronously-coupled consensus algorithm so as to make the agents achieve a dynamical consensus. Based on frequency-domain analysis, sufficient conditions are gained for second-order multi-agent systems with communication delay under leaderless and leader-following consensus algorithms respectively. Simulation illustrates the correctness of the results. (interdisciplinary physics and related areas of science and technology)

  11. Are Young People Subjects of Rights or…without rights? Changes in the Contravention System (Cordoba, Argentina

    Directory of Open Access Journals (Sweden)

    Mariana Jesica Lerchundi

    2017-01-01

    Full Text Available This text wants to compare the main differences between the Faults Code and Coexistence Code of the Province of Córdoba (Argentina taking young people as empirical subjects of reflection, which are the most affected by the regulations. From the content analysis and critical discourse analysis, the differences between the two standards were found. Here are detailed only some of them that allow us to infer changes in the penal system maintaining the violation of rights of young people.

  12. Buckling calculations with the CEASEMT system for elliptical heads subjected to an internal pressure. Comparison with the Saclay experiments

    International Nuclear Information System (INIS)

    Bung, Hariddh; Alix, Michel; Hoffmann, Alain.

    1980-06-01

    In this paper, Buckling calculations with the CEASEMT System (INCA) are compared with experimental results obtained on elliptical heads subjected to an internal pressure. Tests were performed with 18 ellipsoidal heads welded on cylinders made of carbon steel A 36-401, stainless steel Z6CN18-09 and aluminium-magnesium alloys (AG3). Experimental data are higher than calculated data, this leads to a good safety factor [fr

  13. SCREENING OF MEDIUM COMPOUNDS USING A TWO-LEVEL FACTORIAL DESIGN FOR SACCHAROMYCES BOULARDII

    Directory of Open Access Journals (Sweden)

    GUOWEI SHU

    2016-04-01

    Full Text Available Even if the probiotic effect of Saccharomyces boulardii is has been reported, this yeast is rarely used in medium composition. Based on single factor experiment, two-level factorial design was employed to evaluate the effect of carbon sources (sucrose, glucose, nitrogen sources (soy peptone, beef extract, yeast extract, calf serum, malt extract and salts (K2HPO4, KH2PO4, MgSO4, Na2HPO4, NaH2PO4, CaCl2, sodium citrate, sodium glutamate on the growth of S. boulardii. At the same time, the optical density (OD in the medium was measured at 560 nm after 36 h of incubation. The result of two-level factorial design experiment showed that calf serum (p = 0.0214 and sodium citrate (p = 0.0045 are the significant growth factors of S. boulardii, sucrose (p = 0.0861 and malt extract (p = 0.0763 are important factors. In addition, sucrose and sodium citrate showed positive effect on the growth of S. boulardii. However, calf serum and malt extract showed negative effect on the growth. And we determined that the optimum medium composition for S. boulardii was as follow: 37.5 g·L-1 sucrose, 6 g·L-1 calf serum, 6 g·L-1 malt extract, 5 g·L-1 sodium citrate.

  14. Improved Genetic Algorithm with Two-Level Approximation for Truss Optimization by Using Discrete Shape Variables

    Directory of Open Access Journals (Sweden)

    Shen-yan Chen

    2015-01-01

    Full Text Available This paper presents an Improved Genetic Algorithm with Two-Level Approximation (IGATA to minimize truss weight by simultaneously optimizing size, shape, and topology variables. On the basis of a previously presented truss sizing/topology optimization method based on two-level approximation and genetic algorithm (GA, a new method for adding shape variables is presented, in which the nodal positions are corresponding to a set of coordinate lists. A uniform optimization model including size/shape/topology variables is established. First, a first-level approximate problem is constructed to transform the original implicit problem to an explicit problem. To solve this explicit problem which involves size/shape/topology variables, GA is used to optimize individuals which include discrete topology variables and shape variables. When calculating the fitness value of each member in the current generation, a second-level approximation method is used to optimize the continuous size variables. With the introduction of shape variables, the original optimization algorithm was improved in individual coding strategy as well as GA execution techniques. Meanwhile, the update strategy of the first-level approximation problem was also improved. The results of numerical examples show that the proposed method is effective in dealing with the three kinds of design variables simultaneously, and the required computational cost for structural analysis is quite small.

  15. Two-level method for unsteady Navier-Stokes equations based on a new projection

    International Nuclear Information System (INIS)

    Hou Yanren; Li Kaitai

    2004-12-01

    A two-level algorithm for the two dimensional unsteady Navier-Stokes equations based on a new projection is proposed and investigated. The approximate solution is solved as a sum of a large eddy component and a small eddy component, which are in the sense of the new projection, constructed in this paper. These two terms advance in time explicitly. Actually, the new algorithm proposed here can be regarded as a sort of postprocessing algorithm for the standard Galerkin method (SGM). The large eddy part is solved by SGM in the usual L 2 -based large eddy subspace while the small eddy part (the correction part) is obtained in its complement subspace in the sense of the new projection. The stability analysis indicates the improvement of the stability comparing with SGM of the same scale, and the L 2 -error estimate shows that the scheme can improve the accuracy of SGM approximation for half order. We also propose a numerical implementation based on Lagrange multiplier for this two-level algorithm. (author)

  16. A novel two-level dynamic parallel data scheme for large 3-D SN calculations

    International Nuclear Information System (INIS)

    Sjoden, G.E.; Shedlock, D.; Haghighat, A.; Yi, C.

    2005-01-01

    We introduce a new dynamic parallel memory optimization scheme for executing large scale 3-D discrete ordinates (Sn) simulations on distributed memory parallel computers. In order for parallel transport codes to be truly scalable, they must use parallel data storage, where only the variables that are locally computed are locally stored. Even with parallel data storage for the angular variables, cumulative storage requirements for large discrete ordinates calculations can be prohibitive. To address this problem, Memory Tuning has been implemented into the PENTRAN 3-D parallel discrete ordinates code as an optimized, two-level ('large' array, 'small' array) parallel data storage scheme. Memory Tuning can be described as the process of parallel data memory optimization. Memory Tuning dynamically minimizes the amount of required parallel data in allocated memory on each processor using a statistical sampling algorithm. This algorithm is based on the integral average and standard deviation of the number of fine meshes contained in each coarse mesh in the global problem. Because PENTRAN only stores the locally computed problem phase space, optimal two-level memory assignments can be unique on each node, depending upon the parallel decomposition used (hybrid combinations of angular, energy, or spatial). As demonstrated in the two large discrete ordinates models presented (a storage cask and an OECD MOX Benchmark), Memory Tuning can save a substantial amount of memory per parallel processor, allowing one to accomplish very large scale Sn computations. (authors)

  17. Insulin Sensitivity Determines Effects of Insulin and Meal Ingestion on Systemic Vascular Resistance in Healthy Subjects.

    Science.gov (United States)

    Woerdeman, Jorn; Meijer, Rick I; Eringa, Etto C; Hoekstra, Trynke; Smulders, Yvo M; Serné, Erik H

    2016-01-01

    In addition to insulin's metabolic actions, insulin can dilate arterioles which increase blood flow to metabolically active tissues. This effect is blunted in insulin-resistant subjects. Insulin's effect on SVR, determined by resistance arterioles, has, however, rarely been examined directly. We determined the effects of both hyperinsulinemia and a mixed meal on SVR and its relationship with insulin sensitivity. Thirty-seven lean and obese women underwent a hyperinsulinemic-euglycemic clamp, and 24 obese volunteers underwent a mixed-meal test. SVR was assessed using CPP before and during hyperinsulinemia as well as before and 60 and 120 minutes after a meal. SVR decreased significantly during hyperinsulinemia (-13%; p Insulin decreased SVR more strongly in insulin-sensitive individuals (standardized β: -0.44; p = 0.01). In addition, SVR at 60 minutes after meal ingestion was inversely related to the Matsuda index (β: -0.39; p = 0.04) and the change in postprandial SVR was directly related to postprandial glycemia (β: 0.53; p insulin resistance. This suggests that resistance to insulin-induced vasodilatation contributes to regulation of vascular resistance. © 2015 John Wiley & Sons Ltd.

  18. Input-to-State Stabilizing MPC for Neutrally Stable Linear Systems subject to Input Constraints

    NARCIS (Netherlands)

    Kim, Jung-Su; Yoon, Tae-Woong; Jadbabaie, Ali; Persis, Claudio De

    2004-01-01

    MPC(Model Predictive Control) is representative of control methods which are able to handle physical constraints. Closed-loop stability can therefore be ensured only locally in the presence of constraints of this type. However, if the system is neutrally stable, and if the constraints are imposed

  19. An Analysis and Design for Nonlinear Quadratic Systems Subject to Nested Saturation

    Directory of Open Access Journals (Sweden)

    Minsong Zhang

    2013-01-01

    Full Text Available This paper considers the stability problem for nonlinear quadratic systems with nested saturation input. The interesting treatment method proposed to nested saturation here is put into use a well-established linear differential control tool. And the new conclusions include the existing conclusion on this issue and have less conservatism than before. Simulation example illustrates the effectiveness of the established methodologies.

  20. Analysis of ventilation systems subjected to tornado conditions, May 1--September 30, 1977

    International Nuclear Information System (INIS)

    Andrae, R.W.; Duerre, K.H.; Dove, R.C.; Smith, M.H.; Gregory, W.S.

    1978-12-01

    A computer code called TVENT was developed to predict variations of pressure and flow induced in nuclear facility ventilation systems by a tornado. The final revisions made to TVENT that resulted from the suggestions of several users and the application of TVENT by the Los Alamos Scientific Laboratory (LASL) to real ventilation systems, such as those in the new LASL plutonium facility are described. TVENT was also used in an investigation of scale-modeling laws for ventilation systems. Application of TVENT to the LASL plutonium facility demonstrated that the code will handle large, complex systems. The results showed that tornado-induced transients would produce pressure reversals between zones and high flow through the filters in some plenums. The investigation of any serious implications of these conditions will require a separate effort that is beyond the scope of this report. Scale models based on several different assumptions were analyzed using TVENT to determine the best approach in building a scale model. One model distorted viscosity, and another distorted compressibility. Comparison of the distorted model results with results obtained using full-scale dimensions showed conclusively that compressibility should not be distorted, but that viscosity can be distorted without significant effects

  1. Subjective image quality comparison between two digital dental radiographic systems and conventional dental film

    Directory of Open Access Journals (Sweden)

    Muhammed Ajmal

    2014-10-01

    Recommendations: Improved software and hardware for digital imaging systems are now available and these improvements may now yield images that are comparable in quality to conventional film. However, we recommend that studies still use more observers and other statistical methods to produce ideal results.

  2. Adaptive pulse amplitude pulse width control of systems subject to Coulomb and viscous friction

    NARCIS (Netherlands)

    Wijdeven, van de J.J.M.; Singh, T.

    2003-01-01

    The focus of this paper is on adaptive controlof maneuvering rigid bodies in the presence offriction. The paper describes a simple techniquewhich include Pulse Amplitude and Pulse Widthmodulation to progressively move the system tothe desired final position. To account for uncertaintyin estimated

  3. SOME ASPECTS OF IMMUNE SYSTEM FUNCTIONING IN HEALTHY DONORS SUBJECTED TO XENOGENOUS EXPOSURE

    Directory of Open Access Journals (Sweden)

    O. O. Obukhova

    2006-01-01

    Full Text Available Abstract. In present work, we studied some interrelations between tobacco smoking and the processes of immune system stimulation in healthy blood donors. In our opinion, this issue is especially important for the big industrial center, with rather strong antigenic exposure of the organism. The levels of circulating immune complexes (CIC were used as a marker index which reflects specific antigen-antibody interactions during inflammation. According to the results obtained, the majority of persons who have high CIC levels were tobacco smokers (53.76%. Moreover, the percentage of persons with high CIC content, like as the mean values of this index is increased proportionally to the duration of smoking. A mixture of tobacco smoke components seems to exert direct toxic effect upon various compartments of the immune system and causes local irritation of bronchial tree, thus producing local and systemic inflammatory reaction. It is, possibly, an additional factor which determines activation of immune system, with a background of adverse antropogenic exposures typical to industrial centers. The data obtained allow us to affirm a toxic action of tobacco smoke upon the organism of smokers, with development of inflammatory reactions that are displayed as increased CIC levels at preclinical stage.

  4. Performance assessment of topologically diverse power systems subjected to hurricane events

    International Nuclear Information System (INIS)

    Winkler, James; Duenas-Osorio, Leonardo; Stein, Robert; Subramanian, Devika

    2010-01-01

    Large tropical cyclones cause severe damage to major cities along the United States Gulf Coast annually. A diverse collection of engineering and statistical models are currently used to estimate the geographical distribution of power outage probabilities stemming from these hurricanes to aid in storm preparedness and recovery efforts. Graph theoretic studies of power networks have separately attempted to link abstract network topology to transmission and distribution system reliability. However, few works have employed both techniques to unravel the intimate connection between network damage arising from storms, topology, and system reliability. This investigation presents a new methodology combining hurricane damage predictions and topological assessment to characterize the impact of hurricanes upon power system reliability. Component fragility models are applied to predict failure probability for individual transmission and distribution power network elements simultaneously. The damage model is calibrated using power network component failure data for Harris County, TX, USA caused by Hurricane Ike in September of 2008, resulting in a mean outage prediction error of 15.59% and low standard deviation. Simulated hurricane events are then applied to measure the hurricane reliability of three topologically distinct transmission networks. The rate of system performance decline is shown to depend on their topological structure. Reliability is found to correlate directly with topological features, such as network meshedness, centrality, and clustering, and the compact irregular ring mesh topology is identified as particularly favorable, which can influence regional lifeline policy for retrofit and hardening activities to withstand hurricane events.

  5. Inter-subject Functional Correlation Reveal a Hierarchical Organization of Extrinsic and Intrinsic Systems in the Brain.

    Science.gov (United States)

    Ren, Yudan; Nguyen, Vinh Thai; Guo, Lei; Guo, Christine Cong

    2017-09-07

    The brain is constantly monitoring and integrating both cues from the external world and signals generated intrinsically. These extrinsically and intrinsically-driven neural processes are thought to engage anatomically distinct regions, which are thought to constitute the extrinsic and intrinsic systems of the brain. While the specialization of extrinsic and intrinsic system is evident in primary and secondary sensory cortices, a systematic mapping of the whole brain remains elusive. Here, we characterized the extrinsic and intrinsic functional activities in the brain during naturalistic movie-viewing. Using a novel inter-subject functional correlation (ISFC) analysis, we found that the strength of ISFC shifts along the hierarchical organization of the brain. Primary sensory cortices appear to have strong inter-subject functional correlation, consistent with their role in processing exogenous information, while heteromodal regions that attend to endogenous processes have low inter-subject functional correlation. Those brain systems with higher intrinsic tendency show greater inter-individual variability, likely reflecting the aspects of brain connectivity architecture unique to individuals. Our study presents a novel framework for dissecting extrinsically- and intrinsically-driven processes, as well as examining individual differences in brain function during naturalistic stimulation.

  6. Seismic response analysis of a piping system subjected to multiple support excitations in a base isolated NPP building

    International Nuclear Information System (INIS)

    Surh, Han-Bum; Ryu, Tae-Young; Park, Jin-Sung; Ahn, Eun-Woo; Choi, Chul-Sun; Koo, Ja Choon; Choi, Jae-Boong; Kim, Moon Ki

    2015-01-01

    Highlights: • Piping system in the APR 1400 NPP with a base isolation design is studied. • Seismic response of piping system in base isolated building are investigated. • Stress classification method is examined for piping subjected to seismic loading. • Primary stress of piping is reduced due to base isolation design. • Substantial secondary stress is observed in the main steam piping. - Abstract: In this study, the stress response of the piping system in the advanced power reactor 1400 (APR 1400) with a base isolation design subjected to seismic loading is addressed. The piping system located between the auxiliary building with base isolation and the turbine building with a fixed base is considered since it can be subjected to substantial relative support movement during seismic events. First, the support responses with respect to the base characteristic are investigated to perform seismic analysis for multiple support excitations. Finite element analyses are performed to predict the piping stress response through various analysis methods such as the response spectrum, seismic support movement and time history method. To separately evaluate the inertial effect and support movement effect on the piping stress, the stress is decomposed into a primary and secondary stress using the proposed method. Finally, influences of the base isolation design on the piping system in the APR 1400 are addressed. The primary stress based on the inertial loading is effectively reduced in a base isolation design, whereas a considerable amount of secondary stress is generated in the piping system connecting a base isolated building with a fixed base building. It is also confirmed that both the response spectrum analysis and seismic support movement analysis provide more conservative estimations of the piping stress compared to the time history analysis

  7. Identification of fractional-order systems via a switching differential evolution subject to noise perturbations

    International Nuclear Information System (INIS)

    Zhu, Wu; Fang, Jian-an; Tang, Yang; Zhang, Wenbing; Xu, Yulong

    2012-01-01

    In this Letter, a differential evolution variant, called switching DE (SDE), has been employed to estimate the orders and parameters in incommensurate fractional-order chaotic systems. The proposed algorithm includes a switching population utilization strategy, where the population size is adjusted dynamically based on the solution-searching status. Thus, this adaptive control method realizes the identification of fractional-order Lorenz, Lü and Chen systems in both deterministic and stochastic environments, respectively. Numerical simulations are provided, where comparisons are made with five other State-of-the-Art evolutionary algorithms (EAs) to verify the effectiveness of the proposed method. -- Highlights: ► Switching population utilization strategy is applied for differential evolution. ► The parameters are estimated in both deterministic and stochastic environments. ► Comparisons with five other EAs verify the effectiveness of the proposed method.

  8. Identification of fractional-order systems via a switching differential evolution subject to noise perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Wu, E-mail: dtzhuwu@gmail.com [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Fang, Jian-an [College of Information Science and Technology, Donghua University, Shanghai 201620 (China); Tang, Yang, E-mail: yang.tang@pik-potsdam.de [Institute of Physics, Humboldt University, Berlin 12489 (Germany); Potsdam Institute for Climate Impact Research, Potsdam 14415 (Germany); Research Institute for Intelligent Control and System, Harbin Institute of Technology, Harbin 150006 (China); Zhang, Wenbing [Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hong Kong (China); Xu, Yulong [College of Information Science and Technology, Donghua University, Shanghai 201620 (China)

    2012-10-01

    In this Letter, a differential evolution variant, called switching DE (SDE), has been employed to estimate the orders and parameters in incommensurate fractional-order chaotic systems. The proposed algorithm includes a switching population utilization strategy, where the population size is adjusted dynamically based on the solution-searching status. Thus, this adaptive control method realizes the identification of fractional-order Lorenz, Lü and Chen systems in both deterministic and stochastic environments, respectively. Numerical simulations are provided, where comparisons are made with five other State-of-the-Art evolutionary algorithms (EAs) to verify the effectiveness of the proposed method. -- Highlights: ► Switching population utilization strategy is applied for differential evolution. ► The parameters are estimated in both deterministic and stochastic environments. ► Comparisons with five other EAs verify the effectiveness of the proposed method.

  9. Biocorrosion and biofilm formation in a nutrient limited heating system subjected to alternating microaerophilic conditions.

    Science.gov (United States)

    Kjellerup, B V; Kjeldsen, K U; Lopes, F; Abildgaard, L; Ingvorsen, K; Frølund, B; Sowers, K R; Nielsen, P H

    2009-11-01

    Severe biofilm formation and biocorrosion have been observed in heating systems even when the water quality complied with existing standards. The coupling between water chemistry, biofilm formation, species composition, and biocorrosion in a heating system was investigated by adding low concentrations of nutrients and oxygen under continuous and alternating dosing regimes. Molecular analysis of 16S rRNA gene fragments demonstrated that the amendments did not cause changes in the overall bacterial community composition. The combined alternating dosing of nutrients and oxygen caused increased rates of pitting (bio-) corrosion. Detection of bacteria involved in sulfide production and oxidation by retrieval of the functional dsrAB and apsA genes revealed the presence of Gram-positive sulfate- and sulfite-reducers and an unknown sulfur-oxidizer. Therefore, to control biocorrosion, sources of oxygen and nutrients must be limited, since the effect of the alternating operational conditions apparently is more important than the presence of potentially corrosive biofilm bacteria.

  10. Computer simulation of two-level pedicle subtraction osteotomy for severe thoracolumbar kyphosis in ankylosing spondylitis

    Directory of Open Access Journals (Sweden)

    Ning Zhang

    2017-01-01

    Full Text Available Background: Advanced ankylosing spondylitis is often associated with thoracolumbar kyphosis, resulting in an abnormal spinopelvic balance and pelvic morphology. Different osteotomy techniques have been used to correct AS deformities, unfortunnaly, not all AS patients can gain spinal sagittal balance and good horizontal vision after osteotomy. Materials and Methods: Fourteen consecutive AS patients with severe thoracolumbar kyphosis who were treated with two-level PSO were studied retrospectively. All were male with a mean age of 34.9 ± 9.6 years. The followup ranged from 1–5 years. Preoperative computer simulations using the Surgimap Spinal software were performed for all patients, and the osteotomy level and angle determined from the computer simulation were used surgically. Spinal sagittal parameters were measured preoperatively, after the computer simulation, and postoperatively and included thoracic kyphosis (TK, lumbar lordosis (LL, sagittal vertical axis (SVA, pelvic incidence, pelvic tilt (PT, and sacral slope (SS. The level of correlation between the computer simulation and postoperative parameters was evaluated, and the differences between preoperative and postoperative parameters were compared. The visual analog scale (VAS for back pain and clinical outcome was also assessed. Results: Six cases underwent PSO at L1 and L3, five cases at L2 and T12, and three cases at L3 and T12. TK was corrected from 57.8 ± 15.2° preoperatively to 45.3 ± 7.7° postoperatively (P < 0.05, LL from 9.3 ± 17.5° to −52.3 ± 3.9° (P < 0.001, SVA from 154.5 ± 36.7 to 37.8 ± 8.4 mm (P < 0.001, PT from 43.3 ± 6.1° to 18.0 ± 0.9° (P < 0.001, and SS from 0.8 ± 7.0° to 26.5 ± 10.6° (P < 0.001. The LL, VAS, and PT of the simulated two-level PSO were highly consistent with, or almost the same as, the postoperative parameters. The correlations between the computer simulations and postoperative parameters were significant. The VAS decreased

  11. Adaptive evolution of body size subject to indirect effect in trophic cascade system.

    Science.gov (United States)

    Wang, Xin; Fan, Meng; Hao, Lina

    2017-09-01

    Trophic cascades represent a classic example of indirect effect and are wide-spread in nature. Their ecological impact are well established, but the evolutionary consequences have received even less theoretical attention. We theoretically and numerically investigate the trait (i.e., body size of consumer) evolution in response to indirect effect in a trophic cascade system. By applying the quantitative trait evolutionary theory and the adaptive dynamic theory, we formulate and explore two different types of eco-evolutionary resource-consumer-predator trophic cascade model. First, an eco-evolutionary model incorporating the rapid evolution is formulated to investigate the effect of rapid evolution of the consumer's body size, and to explore the impact of density-mediate indirect effect on the population dynamics and trait dynamics. Next, by employing the adaptive dynamic theory, a long-term evolutionary model of consumer body size is formulated to evaluate the effect of long-term evolution on the population dynamics and the effect of trait-mediate indirect effect. Those models admit rich dynamics that has not been observed yet in empirical studies. It is found that, both in the trait-mediated and density-mediated system, the body size of consumer in predator-consumer-resource interaction (indirect effect) evolves smaller than that in consumer-resource and predator-consumer interaction (direct effect). Moreover, in the density-mediated system, we found that the evolution of consumer body size contributes to avoiding consumer extinction (i.e., evolutionary rescue). The trait-mediate and density-mediate effects may produce opposite evolutionary response. This study suggests that the trophic cascade indirect effect affects consumer evolution, highlights a more comprehensive mechanistic understanding of the intricate interplay between ecological and evolutionary force. The modeling approaches provide avenue for study on indirect effects from an evolutionary perspective

  12. Design of a bolted flange subjected to severe nuclear system thermal transients - A case study

    International Nuclear Information System (INIS)

    Palmer, W.J.; Tomawski, R.J.; Ezekoye, L.I.; Lacey, M.L.

    1986-01-01

    Flange design standards recognize that flanged joints may develop leakage should they be exposed to severe thermal gradients and recommend that such operating conditions be avoided. In nuclear power plants, severe thermal transients may be encountered in many plant and system operating and test conditions. In such applications, conformance with standard design practice may not ensure a leak-tight joint. This paper describes the proper consideration of thermal effects on flanged joints and how that can lead to the development of a successful leak-tight design. Similar procedures may be applied generally to evaluate and upgrade flanged joints in thermal shock applications

  13. Analysis of ventilation systems subjected to explosive transients: far-field analysis

    International Nuclear Information System (INIS)

    Tang, P.K.; Andrae, R.W.; Bolstad, J.W.; Duerre, K.H.; Gregory, W.S.

    1981-11-01

    Progress in developing a far-field explosion simulation computer code is outlined. The term far-field implies that this computer code is suitable for modeling explosive transients in ventilation systems that are far removed from the explosive event and are rather insensitive to the particular characteristics of the explosive event. This type of analysis is useful when little detailed information is available and the explosive event is described parametrically. The code retains all the features of the TVENT code and allows completely compressible flow with inertia and choking effects. Problems that illustrate the capabilities and limitations of the code are described

  14. Comparison of the effects of growth hormone on acylated ghrelin and following acute intermittent exercise in two levels of obesity

    Directory of Open Access Journals (Sweden)

    Majid Gholipour

    2013-08-01

    Full Text Available Background: The prevalence of obesity has risen enormously over the past few decad-es. Both food intake (Appetite and energy expenditure can influence body weight. Acylated ghrelin enhances appetite, and its plasma level is suppressed by growth horm-one. The present study, examines the effects of an intermittent exercise with progress-ive intensities on acylated ghrelin, appetite, and growth hormone in inactive male students with two levels of obesity.Methods: Eleven inactive males were allocated into two groups on the basis of their body mass index (BMI. Six subjects in group one, BMI= 31.18±0.92 kg/m2, and five subjects in group two, BMI= 36.94±2.25 kg/m2, ran on the treadmill with progressive intensities of 50, 60, 70 and 80% of VO2max for 10, 10, 5, and 2 min respectively. Blood samples were collected before the exercise (as the resting values, after each workload (during the exercise, and at 30, 60, and 120 min (during recovery.Results: Plasma acylated ghrelin concentrations and hunger ratings in two groups were decreased and remained significantly lower than resting values (P=0.008 and P=0.002 respectively at the end of the trial and there was no significant differences between groups. Growth hormone levels in two groups were increased and remained significant-ly higher than resting values (groups one P=0.012, group two P=0.005 at the end of the trial and there was no significant differences between groups. In addition, there were no significant differences between area under the curves (AUC values over total periods for acylated ghrelin, hunger ratings, and growth hormone in two groups.Conclusion: These findings indicate that individuals with two levels of obesity have the same response to the different intensities of treadmill running and two hours thereafter during recovery period, which can be considered for designing a more effective weighting loss training program.

  15. Propagation of an attosecond pulse in a dense two-level medium

    International Nuclear Information System (INIS)

    Song Xiaohong; Gong Shangqing; Yang Weifeng; Xu Zhizhan

    2004-01-01

    We investigate the propagation of attosecond pulse in a dense two-level medium by using an iterative predictor-corrector finite-difference time-domain method. We find when attosecond pulse is considered, that the standard area theorem will break down even for small area pulses: ideal self-induced transparency cannot occur even for a 2π pulse, while the pulses whose areas are not integer multiples of 2π, such as 1.8π and 2.2π pulses, cannot evolve to 2π pulses as predicted by the standard area theorem. Significantly higher spectra components can occur on all these small area propagating pulses due to strong carrier reshaping. Furthermore, these higher spectral components dependent sensitively on the pulse area: the larger the pulse area is, the more evident are these higher spectral components

  16. Estimation of Missing Observations in Two-Level Split-Plot Designs

    DEFF Research Database (Denmark)

    Almimi, Ashraf A.; Kulahci, Murat; Montgomery, Douglas C.

    2008-01-01

    Inserting estimates for the missing observations from split-plot designs restores their balanced or orthogonal structure and alleviates the difficulties in the statistical analysis. In this article, we extend a method due to Draper and Stoneman to estimate the missing observations from unreplicated...... two-level factorial and fractional factorial split-plot (FSP and FFSP) designs. The missing observations, which can either be from the same whole plot, from different whole plots, or comprise entire whole plots, are estimated by equating to zero a number of specific contrast columns equal...... to the number of the missing observations. These estimates are inserted into the design table and the estimates for the remaining effects (or alias chains of effects as the case with FFSP designs) are plotted on two half-normal plots: one for the whole-plot effects and the other for the subplot effects...

  17. Thermal analysis of multi-MW two-level wind power converter

    DEFF Research Database (Denmark)

    Zhou, Dao; Blaabjerg, Frede; Mogens, Lau

    2012-01-01

    In this paper, the multi-MW wind turbine of partial-scale and full-scale two-level power converter with DFIG and direct-drive PMSG are designed and compared in terms of their thermal performance. Simulations of different configurations regarding loss distribution and junction temperature...... in the power device in the whole range of wind speed are presented and analyzed. It is concluded that in both partial-scale and full-scale power converter the most thermal stressed power device in the generator-side converter will have higher mean junction temperature and larger junction temperature...... fluctuation compared to grid-side converter at the rated wind speed. Moreover, the thermal performance of the generator-side converter in the partial-scale power converter becomes crucial around the synchronous operating point and should be considered carefully....

  18. Two-Level Verification of Data Integrity for Data Storage in Cloud Computing

    Science.gov (United States)

    Xu, Guangwei; Chen, Chunlin; Wang, Hongya; Zang, Zhuping; Pang, Mugen; Jiang, Ping

    Data storage in cloud computing can save capital expenditure and relive burden of storage management for users. As the lose or corruption of files stored may happen, many researchers focus on the verification of data integrity. However, massive users often bring large numbers of verifying tasks for the auditor. Moreover, users also need to pay extra fee for these verifying tasks beyond storage fee. Therefore, we propose a two-level verification of data integrity to alleviate these problems. The key idea is to routinely verify the data integrity by users and arbitrate the challenge between the user and cloud provider by the auditor according to the MACs and ϕ values. The extensive performance simulations show that the proposed scheme obviously decreases auditor's verifying tasks and the ratio of wrong arbitration.

  19. TWO-LEVEL HIERARCHICAL COORDINATION QUEUING METHOD FOR TELECOMMUNICATION NETWORK NODES

    Directory of Open Access Journals (Sweden)

    M. V. Semenyaka

    2014-07-01

    Full Text Available The paper presents hierarchical coordination queuing method. Within the proposed method a queuing problem has been reduced to optimization problem solving that was presented as two-level hierarchical structure. The required distribution of flows and bandwidth allocation was calculated at the first level independently for each macro-queue; at the second level solutions obtained on lower level for each queue were coordinated in order to prevent probable network link overload. The method of goal coordination has been determined for multilevel structure managing, which makes it possible to define the order for consideration of queue cooperation restrictions and calculation tasks distribution between levels of hierarchy. Decisions coordination was performed by the method of Lagrange multipliers. The study of method convergence has been carried out by analytical modeling.

  20. Intensity profiles of superdeformed bands in Pb isotopes in a two-level mixing model

    International Nuclear Information System (INIS)

    Wilson, A. N.; Szigeti, S. S.; Rogers, J. I.; Davidson, P. M.; Cardamone, D. M.

    2009-01-01

    A recently developed two-level mixing model of the decay out of superdeformed bands is applied to examine the loss of flux from the yrast superdeformed bands in 192 Pb, 194 Pb, and 196 Pb. Probability distributions for decay to states at normal deformations are calculated at each level. The sensitivity of the results to parameters describing the levels at normal deformation and their coupling to levels in the superdeformed well is explored. It is found that except for narrow ranges of the interaction strength coupling the states, the amount of intensity lost is primarily determined by the ratio of γ decay widths in the normal and superdeformed wells. It is also found that while the model can accommodate the observed fractional intensity loss profiles for decay from bands at relatively high excitation, it cannot accommodate the similarly abrupt decay from bands at lower energies if standard estimates of the properties of the states in the first minimum are employed

  1. Photon echo with a few photons in two-level atoms

    International Nuclear Information System (INIS)

    Bonarota, M; Dajczgewand, J; Louchet-Chauvet, A; Le Gouët, J-L; Chanelière, T

    2014-01-01

    To store and retrieve signals at the single photon level, various photon echo schemes have resorted to complex preparation steps involving ancillary shelving states in multi-level atoms. For the first time, we experimentally demonstrate photon echo operation at such a low signal intensity without any preparation step, which allows us to work with mere two-level atoms. This simplified approach relies on the so-coined ‘revival of silenced echo’ (ROSE) scheme. Low noise conditions are obtained by returning the atoms to the ground state before the echo emission. In the present paper we manage ROSE in photon counting conditions, showing that very strong control fields can be compatible with extremely weak signals, making ROSE consistent with quantum memory requirements. (paper)

  2. Indoor Semantic Modelling for Routing: The Two-Level Routing Approach for Indoor Navigation

    Directory of Open Access Journals (Sweden)

    Liu Liu

    2017-11-01

    Full Text Available Humans perform many activities indoors and they show a growing need for indoor navigation, especially in unfamiliar buildings such as airports, museums and hospitals. Complexity of such buildings poses many challenges for building managers and visitors. Indoor navigation services play an important role in supporting these indoor activities. Indoor navigation covers extensive topics such as: 1 indoor positioning and localization; 2 indoor space representation for navigation model generation; 3 indoor routing computation; 4 human wayfinding behaviours; and 5 indoor guidance (e.g., textual directories. So far, a large number of studies of pedestrian indoor navigation have presented diverse navigation models and routing algorithms/methods. However, the major challenge is rarely referred to: how to represent the complex indoor environment for pedestrians and conduct routing according to the different roles and sizes of users. Such complex buildings contain irregular shapes, large open spaces, complicated obstacles and different types of passages. A navigation model can be very complicated if the indoors are accurately represented. Although most research demonstrates feasible indoor navigation models and related routing methods in regular buildings, the focus is still on a general navigation model for pedestrians who are simplified as circles. In fact, pedestrians represent different sizes, motion abilities and preferences (e.g., described in user profiles, which should be reflected in navigation models and be considered for indoor routing (e.g., relevant Spaces of Interest and Points of Interest. In order to address this challenge, this thesis proposes an innovative indoor modelling and routing approach – two-level routing. It specially targets the case of routing in complex buildings for distinct users. The conceptual (first level uses general free indoor spaces: this is represented by the logical network whose nodes represent the spaces and edges

  3. Inverse problem for a two-level medium with an inhomgeneously broadened transition in the field of a periodic wave

    International Nuclear Information System (INIS)

    Zabolotskii, A.A.

    1995-01-01

    The inverse problem is considered for a spectral problem, which is formally equivalent to a system of Bloch equations for an inhomogeneously broadened transition interacting with the electric field. Two cases are considered to demonstrate that, for any given frequency interval, one can determine the pulse of the shape which corresponds to the interaction with only this frequency interval. In the general case, the pulse shape is described by a nonlinear periodic wave. The first example is the resonance interaction of light with a gas of two-level atoms. The second example is interaction of a linearly polarized light with the molecular J-J transition, where J much-gt 1. In the latter case, the role of inhomogeneous broadening belongs to the frequency shift induced by the applied magnetic field. 10 refs

  4. Cascaded two-photon nonlinearity in a one-dimensional waveguide with multiple two-level emitters

    Science.gov (United States)

    Roy, Dibyendu

    2013-01-01

    We propose and theoretically investigate a model to realize cascaded optical nonlinearity with few atoms and photons in one-dimension (1D). The optical nonlinearity in our system is mediated by resonant interactions of photons with two-level emitters, such as atoms or quantum dots in a 1D photonic waveguide. Multi-photon transmission in the waveguide is nonreciprocal when the emitters have different transition energies. Our theory provides a clear physical understanding of the origin of nonreciprocity in the presence of cascaded nonlinearity. We show how various two-photon nonlinear effects including spatial attraction and repulsion between photons, background fluorescence can be tuned by changing the number of emitters and the coupling between emitters (controlled by the separation). PMID:23948782

  5. Dynamics of a trapped two-level and three-level atom interacting with classical electromagnetic field

    International Nuclear Information System (INIS)

    Ray, Aditi

    2004-01-01

    The dynamics of a two-level atom driven by a single laser beam and three-level atom (Lambda configuration) irradiated by two laser beams are studied taking into account of the quantized center-of-mass motion of the atom. It is shown that the trapped atom system under appropriate resonance condition exhibits the large time-scale revivals when the index of the vibrational sideband responsible for the atomic electronic transition is greater than unity. The revival times are shown to be dependent on the initial number of vibrational excitations and the magnitude of the Lamb-Dicke parameter. The sub-Poissonian statistics in vibrational quantum number is observed at certain time intervals. The minimum time of interaction for which the squeezed states of motional quadrature are generated is found to be decreasing with the increase in the Lamb-Dicke parameter

  6. The EPQ model under conditions of two levels of trade credit and limited storage capacity in supply chain management

    Science.gov (United States)

    Chung, Kun-Jen

    2013-09-01

    An inventory problem involves a lot of factors influencing inventory decisions. To understand it, the traditional economic production quantity (EPQ) model plays rather important role for inventory analysis. Although the traditional EPQ models are still widely used in industry, practitioners frequently question validities of assumptions of these models such that their use encounters challenges and difficulties. So, this article tries to present a new inventory model by considering two levels of trade credit, finite replenishment rate and limited storage capacity together to relax the basic assumptions of the traditional EPQ model to improve the environment of the use of it. Keeping in mind cost-minimisation strategy, four easy-to-use theorems are developed to characterise the optimal solution. Finally, the sensitivity analyses are executed to investigate the effects of the various parameters on ordering policies and the annual total relevant costs of the inventory system.

  7. Contour integral computations for multi-component material systems subjected to creep

    International Nuclear Information System (INIS)

    Chen, J.-J.; Tu, S.-T.; Xuan, F.-Z.; Wang, Z.-D.

    2006-01-01

    In the present paper the crack behavior of multi-component material systems is investigated under extensive creep condition. The validation of the creep fracture parameters C* and C(t) is firstly examined at the microscale level. It is found that the C* value is no longer path-independent when mismatch inclusions are embedded into the matrix. To characterize the crack fields in inhomogeneous material the integral value defined at the crack tip as C tip * is introduced to reflect the influence of the inclusion. The interaction effects between microcrack and inclusion are systematically calculated with respect to different mismatch factors, various inclusion locations and inclusion numbers. The analysis results show that the C tip * value is not only influenced by the inclusion properties but also depends on the microstructure near the crack tip

  8. Optical scatterometry system for detecting specific line edge roughness of resist gratings subjected to detector noises

    International Nuclear Information System (INIS)

    Lee, Yen-Min; Li, Jia-Han; Cheng, Hsin-Hung; Wang, Fu-Min; Shen, Yu-Tian; Tsai, Kuen-Yu; Shieh, Jason J; Chen, Alek C

    2014-01-01

    The Fourier scatterometry model was used to measure the ZEP 520A electron beam resist lines with specific line edge roughness (LER). By obtaining the pupils via an objective lens, the angle-resolved diffraction spectrum was collected efficiently without additional mechanical scanning. The concavity of the pupil was considered as the weight function in specimen recognition. A series of white noises was examined in the model, and the tolerant white noise levels for different system numerical apertures (NAs) were reported. Our numerical results show that the scatterometry model of a higher NA can identify a target with a higher white noise level. Moreover, the fabricated ZEP 520A electron beam resist gratings with LER were measured by using our model, and the fitting results were matched with scanning electron microscope measurements. (paper)

  9. Serious infections among a large cohort of subjects with systemically treated psoriasis.

    Science.gov (United States)

    Dobry, Allison S; Quesenberry, Charles P; Ray, G Thomas; Geier, Jamie L; Asgari, Maryam M

    2017-11-01

    Biologic therapy is effective for treatment of moderate-to-severe psoriasis but may be associated with an increased risk for serious infection. To estimate the serious infection rate among patients with psoriasis treated with biologic as compared with nonbiologic systemic agents within a community-based health care delivery setting. We identified 5889 adult Kaiser Permanente Northern California health plan members with psoriasis who had ever been treated with systemic therapies and calculated the incidence rates and 95% confidence intervals (CIs) for serious infections over 29,717 person-years of follow-up. Adjusted hazard ratios (aHRs) were calculated using Cox regression. Adjusting for age, sex, race or ethnicity, and comorbidities revealed a significantly increased risk for overall serious infection among patients treated with biologics as compared with those treated with nonbiologics (aHR, 1.31; 95% CI, 1.02-1.68). More specifically, there was a significantly elevated risk for skin and soft tissue infection (aHR, 1.75; 95% CI, 1.19-2.56) and meningitis (aHR, 9.22; 95% CI, 1.77-48.10) during periods of active biologic use. Risk associated with individual drugs was not examined. We found an increased rate of skin and soft tissue infections among patients with psoriasis treated with biologic agents. There also was a signal suggesting increased risk for meningitis. Clinicians should be aware of these potential adverse events when prescribing biologic agents. Copyright © 2017 American Academy of Dermatology, Inc. Published by Elsevier Inc. All rights reserved.

  10. Optimal Attack Strategies Subject to Detection Constraints Against Cyber-Physical Systems

    International Nuclear Information System (INIS)

    Chen, Yuan; Kar, Soummya; Moura, Jose M. F.

    2017-01-01

    This paper studies an attacker against a cyberphysical system (CPS) whose goal is to move the state of a CPS to a target state while ensuring that his or her probability of being detected does not exceed a given bound. The attacker’s probability of being detected is related to the nonnegative bias induced by his or her attack on the CPS’s detection statistic. We formulate a linear quadratic cost function that captures the attacker’s control goal and establish constraints on the induced bias that reflect the attacker’s detection-avoidance objectives. When the attacker is constrained to be detected at the false-alarm rate of the detector, we show that the optimal attack strategy reduces to a linear feedback of the attacker’s state estimate. In the case that the attacker’s bias is upper bounded by a positive constant, we provide two algorithms – an optimal algorithm and a sub-optimal, less computationally intensive algorithm – to find suitable attack sequences. Lastly, we illustrate our attack strategies in numerical examples based on a remotely-controlled helicopter under attack.

  11. Systemic Inflammation and Lung Function Impairment in Morbidly Obese Subjects with the Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Astrid van Huisstede

    2013-01-01

    Full Text Available Background. Obesity and asthma are associated. There is a relationship between lung function impairment and the metabolic syndrome. Whether this relationship also exists in the morbidly obese patients is still unknown. Hypothesis. Low-grade systemic inflammation associated with the metabolic syndrome causes inflammation in the lungs and, hence, lung function impairment. Methods. This is cross-sectional study of morbidly obese patients undergoing preoperative screening for bariatric surgery. Metabolic syndrome was assessed according to the revised NCEP-ATP III criteria. Results. A total of 452 patients were included. Patients with the metabolic syndrome (n=293 had significantly higher blood monocyte (mean 5.3 versus 4.9, P=0.044 and eosinophil percentages (median 1.0 versus 0.8, P=0.002, while the total leukocyte count did not differ between the groups. The FEV1/FVC ratio was significantly lower in patients with the metabolic syndrome (76.7% versus 78.2%, P=0.032. Blood eosinophils were associated with FEV1/FVC ratio (adj. B −0.113, P=0.018. Conclusion. Although the difference in FEV1/FVC ratio between the groups is relatively small, in this cross-sectional study, and its clinical relevance may be limited, these data indicate that the presence of the metabolic syndrome may influence lung function impairment, through the induction of relative eosinophilia.

  12. A periodic inspection and replacement policy for systems subject to competing failure modes due to degradation and traumatic events

    Energy Technology Data Exchange (ETDEWEB)

    Huynh, K.T., E-mail: tuan.huynh@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Barros, A., E-mail: anne.barros@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes, Institut Charles Delaunay and STMR UMR CNRS 6279-12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Castro, I.T., E-mail: inmatorres@unex.e [Departamento de Matematicas, Escuela Politecnica, 10071 Caceres (Spain)

    2011-04-15

    This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.

  13. A periodic inspection and replacement policy for systems subject to competing failure modes due to degradation and traumatic events

    International Nuclear Information System (INIS)

    Huynh, K.T.; Barros, A.; Berenguer, C.; Castro, I.T.

    2011-01-01

    This paper deals with the condition-based maintenance of single-unit systems which are subject to the competing and dependent failures due deterioration and traumatic shock events. The main aim is to provide a model to assess the value of condition monitoring information for the maintenance decision-making. A condition-based periodic inspection/replacement policy is developed and compared with a benchmark time-based block replacement policy. Numerical results show that it is indeed useful to follow closely the actual evolution of the system to adapt the maintenance decisions to the true system state to improve the performance of maintenance policies. The analysis of the maintenance costs savings can be used to justify or not the choice to implement a policy based on condition monitoring information and to invest in condition monitoring devices.

  14. Colonic movements in healthy subjects as monitored by a Magnet Tracking System.

    Science.gov (United States)

    Hiroz, P; Schlageter, V; Givel, J-C; Kucera, P

    2009-08-01

    The Magnet Tracking System (MTS) is a minimally-invasive technique of continuous evaluation of gastrointestinal motility. In this study, MTS was used to analyse colonic propulsive dynamics and compare the transit of a magnetic pill with that of standard radio-opaque markers. MTS monitors the progress in real time of a magnetic pill through the gut. Ten men and 10 women with regular daily bowel movements swallowed this pill and 10 radio-opaque markers at 8 pm. Five hours of recordings were conducted during 2 following mornings. Origin, direction, amplitude and velocity of movements were analysed relative to space-time plots of the pill trajectory. Abdominal radiographs were taken to compare the progress of both pill and markers. The magnetic pill lay idle for 90% of its sojourn in the colon; its total retrograde displacement accounted for only 20% of its overall movement. Analysis of these movements showed a bimodal distribution of velocities: around 1.5 and 50 cm min(-1), the latter being responsible for 2/3 of distance traversed. There were more movements overall and more mass movements in males. Net hourly forward progress was greater in the left than right colon, and greater in males. The position of the magnetic pill correlated well with the advancement of markers. MTS showed patterns and propulsion dynamics of colonic segments with as yet unmet precision. Detailed analysis of slow and fast patterns of colonic progress makes it possible to specify the motility of colonic segments, and any variability in gender. Such analysis opens up promising avenues in studies of motility disorders.

  15. Oral supplementation with Lactobacillus delbrueckii subsp. bulgaricus 8481 enhances systemic immunity in elderly subjects.

    Science.gov (United States)

    Moro-García, Marco Antonio; Alonso-Arias, Rebeca; Baltadjieva, Maria; Fernández Benítez, Carlos; Fernández Barrial, Manuel Amadeo; Díaz Ruisánchez, Enrique; Alonso Santos, Ricardo; Alvarez Sánchez, Magdalena; Saavedra Miján, Juan; López-Larrea, Carlos

    2013-08-01

    Throughout life, there is an aging of the immune system that causes impairment of its defense capability. Prevention or delay of this deterioration is considered crucial to maintain general health and increase longevity. We evaluated whether dietary supplementation with Lactobacillus delbrueckii subsp. bulgaricus 8481 could enhance the immune response in the elderly. This multi-center, double-blind, and placebo controlled study enrolled 61 elderly volunteers who were randomly assigned to receive either placebo or probiotics. Each capsule of probiotics contained at least 3 × 10(7)  L. delbrueckii subsp. bulgaricus 8481. Individuals in the study were administered three capsules per day for 6 months. Blood samples were obtained at baseline (time 0), end of month 3, and month 6. We characterized cell subpopulations, measured cytokines by flow cytometry, quantified T cell receptor excision circle (TREC) by real-time PCR (RT-PCR), and determined human β-defensin-2 (hBD-2) concentrations and human cytomegalovirus (CMV) titers by enzyme-linked immunosorbent assay (ELISA). Elderly responded to the intake of probiotic with an increase in the percentage of NK cells, an improvement in the parameters defining the immune risk profile (IRP), and an increase in the T cell subsets that are less differentiated. The probiotic group also showed decreased concentrations of the pro-inflammatory cytokine IL-8 but increased antimicrobial peptide hBD-2. These effects disappeared within 6 months of stopping the probiotic intake. Immunomodulation induced by L. delbrueckii subsp. bulgaricus 8481 could favor the maintenance of an adequate immune response, mainly by slowing the aging of the T cell subpopulations and increasing the number of immature T cells which are potential responders to new antigens.

  16. Fear of happiness predicts subjective and psychological well-being above the behavioral inhibition system (BIS) and behavioral activation system (BAS) model of personality

    OpenAIRE

    Murat Yildirim; Hacer Belen

    2018-01-01

    Fear of happiness is an important psychological construct and has a significant effect on life outcomes such as well-being. This study sought to examine whether fear of happiness could explain variance in subjective well-being and psychological well-being domains after controlling for Behavioral Inhibition System (BIS) and Behavioral Activation System (BAS) Model of Personality. A total of 243 participants (189 males and 54 females) completed Fear of Happiness Scale, Positive-Negative Affect ...

  17. Bond strength of primer/cement systems to zirconia subjected to artificial aging.

    Science.gov (United States)

    Zhao, Li; Jian, Yu-Tao; Wang, Xiao-Dong; Zhao, Ke

    2016-11-01

    Creating reliable and durable adhesion to the nonactive zirconia surface is difficult and has limited zirconia use. The introduction of functional monomers such as 10-methacryloyloxydecyl dihydrogen phosphate (MDP) appears to have enhanced bond strength to zirconia. The purpose of this in vitro study was to evaluate the long-term bond strength of several MDP-containing primer/cement systems to zirconia. Zirconia blocks were divided into 6 groups (n=24) according to the 3 primers/cements to be bonded, as follows: Scotchbond Universal/RelyX Ultimate (SU/RU; consisting of MDP-containing primer/MDP-free cement); Clearfil ceramic primer/Panavia F (CCP/PAN; consisting ofMDP-containing/MDP-containing); and Z-Prime Plus/Duo-Link (ZP/DUO; consisting ofMDP-containing/MDP-free), which were compared with 3 nonprimed groups, RU, PAN, and DUO. After bonding, each group was further divided into 3 subgroups (n=8) according to the level of aging: 24-hour storage in water at 37°C (24H); 30-day storage at 37°C (30D); and 30-day storage at 37°C followed by 3000 thermal cycles (30D/TC). After aging, a shear bond strength test and failure mode analysis were performed. The data were analyzed using 2-way ANOVA (α=.05). After aging, nearly all primer/cement groups presented significantly higher bond strength than the related nonprimed groups for each level of aging (P<.05), except for CCP/PAN versus PAN with 24H (P=.741). SU/RU had the highest bond strength among the groups for all treatments (P<.05), except for CCP/PAN versus SU/RU with 30D/TC (P=.171). Among the nonprimed groups, only RU went through 30D/TC without premature debonding. With 24H and 30D, the failure modes in SU/RU and CCP/PAN were purely mixed, whereas those in the other groups were mainly adhesive, except for RU. The superiority of the initial bond strength in SU/RU may result from some functional components other than MDP. The presence of MDP in the cement did not appear to have a positive effect on long-term bond

  18. Effect of Global Postural Reeducation on cardiovascular system of healthy subjects

    Directory of Open Access Journals (Sweden)

    Elizângela Márcia de Carvalho Abreu

    Full Text Available Objective To evaluate the effect of Global Postural Reeducation (GPR on cardiovascular system by heart rate variability (HRV, blood pressure (BP and heart rate (HR. Materials and methods Seventeen healthy men (22.47 ± 3.02 years were submitted to the postures frog on the floor, frog on the air, sitting, standing against the wall and inclined standing, two postures per session. The systolic and diastolic blood pressure (SBP and DBP and HR were recorded. The intervals between heartbeats were collected during the whole session (Polar S810i. The frequency domain was analyzed (Wavelet Transform, the low frequency (LF and high frequency (HF were obtained. The data were analyzed by ANOVA and Tukey (p < 0.05. Results Increased LF/HF ratio was observed in the frog on the floor (1 ± 0.1 vs. 2 ± 0.3 p < 0.05 and on the air postures (1 ± 0.1 vs. 2 ± 0.2 p < 0.01. There was an increase in SBP in the postures frog on the floor (123 ± 2 vs. 136 ± 4 p < 0.05, frog on the air (122 ± 2 vs. 133 ± 3 p < 0.05, standing against the wall (123 ± 2 vs. 136 ± 4 p < 0.05, inclined standing (124 ± 3 vs. 146 ± 5 p < 0.05. There was increase of DBP in the postures frog on the floor (69 ± 2 vs. 81 ± 2 p < 0.01, frog on the air (72 ± 2 vs. 83 ± 3 p < 0.05, sitting (85 ± 2 vs. 102 ± 3 p < 0.01. There was increase in HR in the postures frog on the air (67 ± 2 vs. 77 ± 3 p < 0.05 and inclined standing (88 ± 3.5 vs. 101 ± 3 p < 0.05. Conclusion The increase in LF/HF ratio and also the BP and HR indicates high sympathetic activity, possibly related to the work isometric developed during GPR method. [P

  19. A SEMI-LAGRANGIAN TWO-LEVEL PRECONDITIONED NEWTON-KRYLOV SOLVER FOR CONSTRAINED DIFFEOMORPHIC IMAGE REGISTRATION.

    Science.gov (United States)

    Mang, Andreas; Biros, George

    2017-01-01

    We propose an efficient numerical algorithm for the solution of diffeomorphic image registration problems. We use a variational formulation constrained by a partial differential equation (PDE), where the constraints are a scalar transport equation. We use a pseudospectral discretization in space and second-order accurate semi-Lagrangian time stepping scheme for the transport equations. We solve for a stationary velocity field using a preconditioned, globalized, matrix-free Newton-Krylov scheme. We propose and test a two-level Hessian preconditioner. We consider two strategies for inverting the preconditioner on the coarse grid: a nested preconditioned conjugate gradient method (exact solve) and a nested Chebyshev iterative method (inexact solve) with a fixed number of iterations. We test the performance of our solver in different synthetic and real-world two-dimensional application scenarios. We study grid convergence and computational efficiency of our new scheme. We compare the performance of our solver against our initial implementation that uses the same spatial discretization but a standard, explicit, second-order Runge-Kutta scheme for the numerical time integration of the transport equations and a single-level preconditioner. Our improved scheme delivers significant speedups over our original implementation. As a highlight, we observe a 20 × speedup for a two dimensional, real world multi-subject medical image registration problem.

  20. Subject-enabled analytics model on measurement statistics in health risk expert system for public health informatics.

    Science.gov (United States)

    Chung, Chi-Jung; Kuo, Yu-Chen; Hsieh, Yun-Yu; Li, Tsai-Chung; Lin, Cheng-Chieh; Liang, Wen-Miin; Liao, Li-Na; Li, Chia-Ing; Lin, Hsueh-Chun

    2017-11-01

    This study applied open source technology to establish a subject-enabled analytics model that can enhance measurement statistics of case studies with the public health data in cloud computing. The infrastructure of the proposed model comprises three domains: 1) the health measurement data warehouse (HMDW) for the case study repository, 2) the self-developed modules of online health risk information statistics (HRIStat) for cloud computing, and 3) the prototype of a Web-based process automation system in statistics (PASIS) for the health risk assessment of case studies with subject-enabled evaluation. The system design employed freeware including Java applications, MySQL, and R packages to drive a health risk expert system (HRES). In the design, the HRIStat modules enforce the typical analytics methods for biomedical statistics, and the PASIS interfaces enable process automation of the HRES for cloud computing. The Web-based model supports both modes, step-by-step analysis and auto-computing process, respectively for preliminary evaluation and real time computation. The proposed model was evaluated by computing prior researches in relation to the epidemiological measurement of diseases that were caused by either heavy metal exposures in the environment or clinical complications in hospital. The simulation validity was approved by the commercial statistics software. The model was installed in a stand-alone computer and in a cloud-server workstation to verify computing performance for a data amount of more than 230K sets. Both setups reached efficiency of about 10 5 sets per second. The Web-based PASIS interface can be used for cloud computing, and the HRIStat module can be flexibly expanded with advanced subjects for measurement statistics. The analytics procedure of the HRES prototype is capable of providing assessment criteria prior to estimating the potential risk to public health. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. DNCON2: improved protein contact prediction using two-level deep convolutional neural networks.

    Science.gov (United States)

    Adhikari, Badri; Hou, Jie; Cheng, Jianlin

    2018-05-01

    Significant improvements in the prediction of protein residue-residue contacts are observed in the recent years. These contacts, predicted using a variety of coevolution-based and machine learning methods, are the key contributors to the recent progress in ab initio protein structure prediction, as demonstrated in the recent CASP experiments. Continuing the development of new methods to reliably predict contact maps is essential to further improve ab initio structure prediction. In this paper we discuss DNCON2, an improved protein contact map predictor based on two-level deep convolutional neural networks. It consists of six convolutional neural networks-the first five predict contacts at 6, 7.5, 8, 8.5 and 10 Å distance thresholds, and the last one uses these five predictions as additional features to predict final contact maps. On the free-modeling datasets in CASP10, 11 and 12 experiments, DNCON2 achieves mean precisions of 35, 50 and 53.4%, respectively, higher than 30.6% by MetaPSICOV on CASP10 dataset, 34% by MetaPSICOV on CASP11 dataset and 46.3% by Raptor-X on CASP12 dataset, when top L/5 long-range contacts are evaluated. We attribute the improved performance of DNCON2 to the inclusion of short- and medium-range contacts into training, two-level approach to prediction, use of the state-of-the-art optimization and activation functions, and a novel deep learning architecture that allows each filter in a convolutional layer to access all the input features of a protein of arbitrary length. The web server of DNCON2 is at http://sysbio.rnet.missouri.edu/dncon2/ where training and testing datasets as well as the predictions for CASP10, 11 and 12 free-modeling datasets can also be downloaded. Its source code is available at https://github.com/multicom-toolbox/DNCON2/. chengji@missouri.edu. Supplementary data are available at Bioinformatics online.

  2. Expanding subjectivities

    DEFF Research Database (Denmark)

    Lundgaard Andersen, Linda; Soldz, Stephen

    2012-01-01

    A major theme in recent psychoanalytic thinking concerns the use of therapist subjectivity, especially “countertransference,” in understanding patients. This thinking converges with and expands developments in qualitative research regarding the use of researcher subjectivity as a tool......-Saxon and continental traditions, this special issue provides examples of the use of researcher subjectivity, informed by psychoanalytic thinking, in expanding research understanding....

  3. Spectral density of Cooper pairs in two level quantum dot–superconductors Josephson junction

    Energy Technology Data Exchange (ETDEWEB)

    Dhyani, A., E-mail: archana.d2003@gmail.com [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Rawat, P.S. [Department of Nuclear Science and Technology, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Tewari, B.S., E-mail: bstewari@ddn.upes.ac.in [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India)

    2016-09-15

    Highlights: • The present work deals with the study of the electronic spectral density of electron pairs and its effect in charge transport in superconductor-quantum dot-superconductor junctions. • The charge transfer across such junctions can be controlled by changing the positions of the dot level. • The Josephson supercurrent can also be tuned by controlling the position of quantum dot energy levels. - Abstract: In the present paper, we report the role of quantum dot energy levels on the electronic spectral density for a two level quantum dot coupled to s-wave superconducting leads. The theoretical arguments in this work are based on the Anderson model so that it necessarily includes dot energies, single particle tunneling and superconducting order parameter for BCS superconductors. The expression for single particle spectral function is obtained by using the Green's function equation of motion technique. On the basis of numerical computation of spectral function of superconducting leads, it has been found that the charge transfer across such junctions can be controlled by the positions and availability of the dot levels.

  4. Induced absorption and stimulated emission in a driven two-level atom

    International Nuclear Information System (INIS)

    Mavroyannis, C.

    1992-01-01

    We have considered the induced processes that occur in a driven two-level atom, where a laser photon is absorbed and emitted by the ground and by the excited states of the atom, respectively. In the low-intensity limit of the laser field, the induced spectra arising when a laser photon is absorbed by the ground state of the atom consist of two peaks describing induced absorption and stimulated-emission processes, respectively, where the former prevails over the latter. Asymmetry of the spectral lines occurs at off-resonance and its extent depends on the detuning of the laser field. The physical. process where a laser photon is emitted by the excited state is the reverse of that arising from the absorption of a laser photon by the ground state of the atom. The former differs from the latter in that the emission of a laser photon by the excited state occurs in the low frequency regime and that the stimulated-emission process prevails over that of the induced absorption. In this case, amplification of ultrashort pulses is likely to occur without the need of population inversion between the optical transitions. The computed spectra are graphically presented and discussed. (author)

  5. Vorticity, backscatter and counter-gradient transport predictions using two-level simulation of turbulent flows

    Science.gov (United States)

    Ranjan, R.; Menon, S.

    2018-04-01

    The two-level simulation (TLS) method evolves both the large-and the small-scale fields in a two-scale approach and has shown good predictive capabilities in both isotropic and wall-bounded high Reynolds number (Re) turbulent flows in the past. Sensitivity and ability of this modelling approach to predict fundamental features (such as backscatter, counter-gradient turbulent transport, small-scale vorticity, etc.) seen in high Re turbulent flows is assessed here by using two direct numerical simulation (DNS) datasets corresponding to a forced isotropic turbulence at Taylor's microscale-based Reynolds number Reλ ≈ 433 and a fully developed turbulent flow in a periodic channel at friction Reynolds number Reτ ≈ 1000. It is shown that TLS captures the dynamics of local co-/counter-gradient transport and backscatter at the requisite scales of interest. These observations are further confirmed through a posteriori investigation of the flow in a periodic channel at Reτ = 2000. The results reveal that the TLS method can capture both the large- and the small-scale flow physics in a consistent manner, and at a reduced overall cost when compared to the estimated DNS or wall-resolved LES cost.

  6. Robust Methods for Moderation Analysis with a Two-Level Regression Model.

    Science.gov (United States)

    Yang, Miao; Yuan, Ke-Hai

    2016-01-01

    Moderation analysis has many applications in social sciences. Most widely used estimation methods for moderation analysis assume that errors are normally distributed and homoscedastic. When these assumptions are not met, the results from a classical moderation analysis can be misleading. For more reliable moderation analysis, this article proposes two robust methods with a two-level regression model when the predictors do not contain measurement error. One method is based on maximum likelihood with Student's t distribution and the other is based on M-estimators with Huber-type weights. An algorithm for obtaining the robust estimators is developed. Consistent estimates of standard errors of the robust estimators are provided. The robust approaches are compared against normal-distribution-based maximum likelihood (NML) with respect to power and accuracy of parameter estimates through a simulation study. Results show that the robust approaches outperform NML under various distributional conditions. Application of the robust methods is illustrated through a real data example. An R program is developed and documented to facilitate the application of the robust methods.

  7. Multilevel Converter by Cascading Two-Level Three-Phase Voltage Source Converter

    Directory of Open Access Journals (Sweden)

    Abdullrahman A. Al-Shamma’a

    2018-04-01

    Full Text Available This paper proposes a topology using isolated, cascaded multilevel voltage source converters (VSCs and employing two-winding magnetic elements for high-power applications. The proposed topology synthesizes 6 two-level, three-phase VSCs, so the power capability of the presented converter is six times the capability of each VSC module. The characteristics of the proposed topology are demonstrated through analyzing its current relationships, voltage relationships and power capability in detail. The power rating is equally shared among the VSC modules without the need for a sharing algorithm; thus, the converter operates as a single three-phase VSC. The comparative analysis with classical neutral-point clamped, flying capacitor and cascaded H-bridge exhibits the superior features of fewer insulated gate bipolar transistors (IGBTs, capacitor requirement and fewer diodes. To validate the theoretical performance of the proposed converter, it is simulated in a MATLAB/Simulink environment and the results are experimentally demonstrated using a laboratory prototype.

  8. Two-Level Evaluation on Sensor Interoperability of Features in Fingerprint Image Segmentation

    Directory of Open Access Journals (Sweden)

    Ya-Shuo Li

    2012-03-01

    Full Text Available Features used in fingerprint segmentation significantly affect the segmentation performance. Various features exhibit different discriminating abilities on fingerprint images derived from different sensors. One feature which has better discriminating ability on images derived from a certain sensor may not adapt to segment images derived from other sensors. This degrades the segmentation performance. This paper empirically analyzes the sensor interoperability problem of segmentation feature, which refers to the feature’s ability to adapt to the raw fingerprints captured by different sensors. To address this issue, this paper presents a two-level feature evaluation method, including the first level feature evaluation based on segmentation error rate and the second level feature evaluation based on decision tree. The proposed method is performed on a number of fingerprint databases which are obtained from various sensors. Experimental results show that the proposed method can effectively evaluate the sensor interoperability of features, and the features with good evaluation results acquire better segmentation accuracies of images originating from different sensors.

  9. Automatic QRS complex detection using two-level convolutional neural network.

    Science.gov (United States)

    Xiang, Yande; Lin, Zhitao; Meng, Jianyi

    2018-01-29

    The QRS complex is the most noticeable feature in the electrocardiogram (ECG) signal, therefore, its detection is critical for ECG signal analysis. The existing detection methods largely depend on hand-crafted manual features and parameters, which may introduce significant computational complexity, especially in the transform domains. In addition, fixed features and parameters are not suitable for detecting various kinds of QRS complexes under different circumstances. In this study, based on 1-D convolutional neural network (CNN), an accurate method for QRS complex detection is proposed. The CNN consists of object-level and part-level CNNs for extracting different grained ECG morphological features automatically. All the extracted morphological features are used by multi-layer perceptron (MLP) for QRS complex detection. Additionally, a simple ECG signal preprocessing technique which only contains difference operation in temporal domain is adopted. Based on the MIT-BIH arrhythmia (MIT-BIH-AR) database, the proposed detection method achieves overall sensitivity Sen = 99.77%, positive predictivity rate PPR = 99.91%, and detection error rate DER = 0.32%. In addition, the performance variation is performed according to different signal-to-noise ratio (SNR) values. An automatic QRS detection method using two-level 1-D CNN and simple signal preprocessing technique is proposed for QRS complex detection. Compared with the state-of-the-art QRS complex detection approaches, experimental results show that the proposed method acquires comparable accuracy.

  10. Injury patterns of child abuse: Experience of two Level 1 pediatric trauma centers.

    Science.gov (United States)

    Yu, Yangyang R; DeMello, Annalyn S; Greeley, Christopher S; Cox, Charles S; Naik-Mathuria, Bindi J; Wesson, David E

    2018-05-01

    This study examines non-accidental trauma (NAT) fatalities as a percentage of all injury fatalities and identifies injury patterns in NAT admissions to two level 1 pediatric trauma centers. We reviewed all children (<5years old) treated for NAT from 2011 to 2015. Patient demographics, injury sites, and survival were obtained from both institutional trauma registries. Of 4623 trauma admissions, 557 (12%) were due to NAT. However, 43 (46%) of 93 overall trauma fatalities were due to NAT. Head injuries were the most common injuries sustained (60%) and led to the greatest increased risk of death (RR 5.1, 95% CI 2.0-12.7). Less common injuries that increased the risk of death were facial injuries (14%, RR 2.9, 95% CI 1.6-5.3), abdominal injuries (8%, RR 2.8, 95% CI 1.4-5.6), and spinal injuries (3%, RR 3.9, 95% CI 1.8-8.8). Although 76% of head injuries occurred in infants <1year, children ages 1-4years old with head injuries had a significantly higher case fatality rate (27% vs. 6%, p<0.001). Child abuse accounts for a large proportion of trauma fatalities in children under 5years of age. Intracranial injuries are common in child abuse and increase the risk of death substantially. Preventing NAT in infants and young children should be a public health priority. Retrospective Review. II. Copyright © 2018. Published by Elsevier Inc.

  11. Two level undercut-profile substrate-based filamentary coated conductors produced using metal organic chemical vapor deposition

    DEFF Research Database (Denmark)

    Insinga, Andrea R.; Sundaram, Aarthi; Hazelton, Drew W.

    2018-01-01

    The two level undercut-profile substrate (2LUPS) has been introduced as a concept for subdividing rare-earth-Ba$_{2}$Cu$_{3}$O$_{7}$ (REBCO) coated conductors (CC) into narrow filaments which reduces the AC losses and improves field stability for DC magnets. The 2LUPS consists of two levels...

  12. Demand response strategy management with active and reactive power incentive in the smart grid: a two-level optimization approach

    Directory of Open Access Journals (Sweden)

    Ryuto Shigenobu

    2017-05-01

    Full Text Available High penetration of distributed generators (DGs using renewable energy sources (RESs is raising some important issues in the operation of modern po­wer system. The output power of RESs fluctuates very steeply, and that include uncertainty with weather conditions. This situation causes voltage deviation and reverse power flow. Several methods have been proposed for solving these problems. Fundamentally, these methods involve reactive power control for voltage deviation and/or the installation of large battery energy storage system (BESS at the interconnection point for reverse power flow. In order to reduce the installation cost of static var compensator (SVC, Distribution Company (DisCo gives reactive power incentive to the cooperating customers. On the other hand, photovoltaic (PV generator, energy storage and electric vehicle (EV are introduced in customer side with the aim of achieving zero net energy homes (ZEHs. This paper proposes not only reactive power control but also active power flow control using house BESS and EV. Moreover, incentive method is proposed to promote participation of customers in the control operation. Demand response (DR system is verified with several DR menu. To create profit for both side of DisCo and customer, two level optimization approach is executed in this research. Mathematical modeling of price elasticity and detailed simulations are executed by case study. The effectiveness of the proposed incentive menu is demonstrated by using heuristic optimization method.

  13. Television system in which digitised picture signals subjected to a transform coding are transmitted from an encoding station to a decoding station

    NARCIS (Netherlands)

    1989-01-01

    Television system in which digitalized picture signals subjected to a transform coding are transmitted from an encoding station to a decoding station. In a television system a digital picture signal is subjected to a transform coding for the purpose of bit rate reduction. In order to detect motion

  14. An EMG-driven exoskeleton hand robotic training device on chronic stroke subjects: task training system for stroke rehabilitation.

    Science.gov (United States)

    Ho, N S K; Tong, K Y; Hu, X L; Fung, K L; Wei, X J; Rong, W; Susanto, E A

    2011-01-01

    An exoskeleton hand robotic training device is specially designed for persons after stroke to provide training on their impaired hand by using an exoskeleton robotic hand which is actively driven by their own muscle signals. It detects the stroke person's intention using his/her surface electromyography (EMG) signals from the hemiplegic side and assists in hand opening or hand closing functional tasks. The robotic system is made up of an embedded controller and a robotic hand module which can be adjusted to fit for different finger length. Eight chronic stroke subjects had been recruited to evaluate the effects of this device. The preliminary results showed significant improvement in hand functions (ARAT) and upper limb functions (FMA) after 20 sessions of robot-assisted hand functions task training. With the use of this light and portable robotic device, stroke patients can now practice more easily for the opening and closing of their hands at their own will, and handle functional daily living tasks at ease. A video is included together with this paper to give a demonstration of the hand robotic system on chronic stroke subjects and it will be presented in the conference. © 2011 IEEE

  15. Fuzzy combination of fuzzy and switching state-feedback controllers for nonlinear systems subject to parameter uncertainties.

    Science.gov (United States)

    Lam, H K; Leung, Frank H F

    2005-04-01

    This paper presents a fuzzy controller, which involves a fuzzy combination of local fuzzy and global switching state-feedback controllers, for nonlinear systems subject to parameter uncertainties with known bounds. The nonlinear system is represented by a fuzzy combined Takagi-Sugeno-Kang model, which is a fuzzy combination of the global and local fuzzy plant models. By combining the local fuzzy and global switching state-feedback controllers using fuzzy logic techniques, the advantages of both controllers can be retained and the undesirable chattering effect introduced by the global switching state-feedback controller can be eliminated. The steady-state error introduced by the global switching state-feedback controller when a saturation function is used can also be removed. Stability conditions, which are related to the system matrices of the local and global closed-loop systems, are derived to guarantee the closed-loop system stability. An application example will be given to demonstrate the merits of the proposed approach.

  16. Reinforcement-Learning-Based Robust Controller Design for Continuous-Time Uncertain Nonlinear Systems Subject to Input Constraints.

    Science.gov (United States)

    Liu, Derong; Yang, Xiong; Wang, Ding; Wei, Qinglai

    2015-07-01

    The design of stabilizing controller for uncertain nonlinear systems with control constraints is a challenging problem. The constrained-input coupled with the inability to identify accurately the uncertainties motivates the design of stabilizing controller based on reinforcement-learning (RL) methods. In this paper, a novel RL-based robust adaptive control algorithm is developed for a class of continuous-time uncertain nonlinear systems subject to input constraints. The robust control problem is converted to the constrained optimal control problem with appropriately selecting value functions for the nominal system. Distinct from typical action-critic dual networks employed in RL, only one critic neural network (NN) is constructed to derive the approximate optimal control. Meanwhile, unlike initial stabilizing control often indispensable in RL, there is no special requirement imposed on the initial control. By utilizing Lyapunov's direct method, the closed-loop optimal control system and the estimated weights of the critic NN are proved to be uniformly ultimately bounded. In addition, the derived approximate optimal control is verified to guarantee the uncertain nonlinear system to be stable in the sense of uniform ultimate boundedness. Two simulation examples are provided to illustrate the effectiveness and applicability of the present approach.

  17. Assessment of colorectal length using the electromagnetic capsule tracking system: a comparative validation study in healthy subjects.

    Science.gov (United States)

    Mark, E B; Poulsen, J L; Haase, A M; Frøkjaer, J B; Schlageter, V; Scott, S M; Krogh, K; Drewes, A M

    2017-09-01

    We aimed to determine colorectal length with the 3D-Transit system by describing a 'centreline' of capsule movement and comparing it with known anatomy, as determined by magnetic resonance imaging (MRI). Further, we aimed to test the day-to-day variation of colorectal length assessed with the system. The 3D-Transit system consists of electromagnetic capsules that can be tracked as they traverse the gastrointestinal tract. Twenty-five healthy subjects were examined with both 3D-Transit and MRI. Another 21 healthy subjects were examined with 3D-Transit on two consecutive days. Computation of colorectal length from capsule passage was possible for 60 of the 67 3D-Transit recordings. The length of the colorectum measured with MRI and 3D-Transit was 95 (75-153) cm and 99 (77-147) cm, respectively (P = 0.15). The coefficient of variation (CV) between MRI and 3D-Transit was 7.8%. Apart from the caecum/ascending colon being 26% (P = 0.002) shorter on MRI, there were no other differences in total or segmental colorectal lengths between methods (all P > 0.05). The length of the colorectum measured with 3D-Transit on two consecutive days was 102 (73-119) cm and 103 (75-123) cm (P = 0.67). The CV between days was 7.3%. The 3D-Transit system allows accurate and reliable determination of colorectal length compared with MRI-derived colorectal length and between days. Antegrade or retrograde capsule movement relative to this centreline, as well as the length and speed of movements, may be determined by future studies to allow better classification and treatment in patients with dysmotility. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

  18. Absorption spectrum of a two-level atom in a bad cavity with injected squeezed vacuum

    Science.gov (United States)

    Zhou, Peng; Swain, S.

    1996-02-01

    We study the absorption spectrum of a coherently driven two-level atom interacting with a resonant cavity mode which is coupled to a broadband squeezed vacuum through its input-output mirror in the bad cavity limit. We study the modification of the two-photon correlation strength of the injected squeezed vacuum inside the cavity, and show that the equations describing probe absorption in the cavity environment are formally identical to these in free space, but with modified parameters describing the squeezed vacuum. The two photon correlations induced by the squeezed vacuum are always weaker than in free space. We pay particular attention to the spectral behaviour at line centre in the region of intermediate trength driving intensities, where anomalous spectral features such as hole-burning and dispersive profiles are displayed. These unusual spectral features are very sensitive to the squeezing phase and the Rabi frequency of the driving field. We also derive the threshold value of the Rabi frequency which gives rise to the transparency of the probe beam at the driving frequency. When the Rabi frequency is less than the threshold value, the probe beam is absorbed, whilst the probe beam is amplified (without population inversion under certain conditions) when the Rabi frequency is larger than this threshold. The anomalous spectral features all take place in the vicinity of the critical point dividing the different dynamical regimes, probe absorption and amplification, of the atomic radiation. The physical origin of the strong amplification without population inversion, and the feasibility of observing it, are discussed.

  19. A two level mutation-selection model of cultural evolution and diversity.

    Science.gov (United States)

    Salazar-Ciudad, Isaac

    2010-11-21

    Cultural evolution is a complex process that can happen at several levels. At the level of individuals in a population, each human bears a set of cultural traits that he or she can transmit to its offspring (vertical transmission) or to other members of his or her society (horizontal transmission). The relative frequency of a cultural trait in a population or society can thus increase or decrease with the relative reproductive success of its bearers (individual's level) or the relative success of transmission (called the idea's level). This article presents a mathematical model on the interplay between these two levels. The first aim of this article is to explore when cultural evolution is driven by the idea's level, when it is driven by the individual's level and when it is driven by both. These three possibilities are explored in relation to (a) the amount of interchange of cultural traits between individuals, (b) the selective pressure acting on individuals, (c) the rate of production of new cultural traits, (d) the individual's capacity to remember cultural traits and to the population size. The aim is to explore the conditions in which cultural evolution does not lead to a better adaptation of individuals to the environment. This is to contrast the spread of fitness-enhancing ideas, which make individual bearers better adapted to the environment, to the spread of "selfish" ideas, which spread well simply because they are easy to remember but do not help their individual bearers (and may even hurt them). At the same time this article explores in which conditions the adaptation of individuals is maximal. The second aim is to explore how these factors affect cultural diversity, or the amount of different cultural traits in a population. This study suggests that a larger interchange of cultural traits between populations could lead to cultural evolution not improving the adaptation of individuals to their environment and to a decrease of cultural diversity

  20. Subjective evaluation of two stereoscopic imaging systems exploiting visual attention to improve 3D quality of experience

    Science.gov (United States)

    Hanhart, Philippe; Ebrahimi, Touradj

    2014-03-01

    Crosstalk and vergence-accommodation rivalry negatively impact the quality of experience (QoE) provided by stereoscopic displays. However, exploiting visual attention and adapting the 3D rendering process on the fly can reduce these drawbacks. In this paper, we propose and evaluate two different approaches that exploit visual attention to improve 3D QoE on stereoscopic displays: an offline system, which uses a saliency map to predict gaze position, and an online system, which uses a remote eye tracking system to measure real time gaze positions. The gaze points were used in conjunction with the disparity map to extract the disparity of the object-of-interest. Horizontal image translation was performed to bring the fixated object on the screen plane. The user preference between standard 3D mode and the two proposed systems was evaluated through a subjective evaluation. Results show that exploiting visual attention significantly improves image quality and visual comfort, with a slight advantage for real time gaze determination. Depth quality is also improved, but the difference is not significant.

  1. Identification of the Response of a Controlled Building Structure Subjected to Seismic Load by Using Nonlinear System Models

    Directory of Open Access Journals (Sweden)

    Mosbeh R. Kaloop

    2016-10-01

    Full Text Available The present study investigates the prediction efficiency of nonlinear system-identification models, in assessing the behavior of a coupled structure-passive vibration controller. Two system-identification models, including Nonlinear AutoRegresive with eXogenous inputs (NARX and adaptive neuro-fuzzy inference system (ANFIS, are used to model the behavior of an experimentally scaled three-story building incorporated with a tuned mass damper (TMD subjected to seismic loads. The experimental study is performed to generate the input and output data sets for training and testing the designed models. The parameters of root-mean-squared error, mean absolute error and determination coefficient statistics are used to compare the performance of the aforementioned models. A TMD controller system works efficiently to mitigate the structural vibration. The results revealed that the NARX and ANFIS models could be used to identify the response of a controlled structure. The parameters of both two time-delays of the structure response and the seismic load were proven to be effective tools in identifying the performance of the models. A comparison based on the parametric evaluation of the two methods showed that the NARX model outperforms the ANFIS model in identifying structures response.

  2. Optimal selective renewal policy for systems subject to propagated failures with global effect and failure isolation phenomena

    International Nuclear Information System (INIS)

    Maaroufi, Ghofrane; Chelbi, Anis; Rezg, Nidhal

    2013-01-01

    This paper considers a selective maintenance policy for multi-component systems for which a minimum level of reliability is required for each mission. Such systems need to be maintained between consecutive missions. The proposed strategy aims at selecting the components to be maintained (renewed) after the completion of each mission such that a required reliability level is warranted up to the next stop with the minimum cost, taking into account the time period allotted for maintenance between missions and the possibility to extend it while paying a penalty cost. This strategy is applied to binary-state systems subject to propagated failures with global effect, and failure isolation phenomena. A set of rules to reduce the solutions space for such complex systems is developed. A numerical example is presented to illustrate the modeling approach and the use of the reduction rules. Finally, the Monte-Carlo simulation is used in combination with the selective maintenance optimization model to deal with a number of successive missions

  3. Effect of propofol on the medial temporal lobe emotional memory system: a functional magnetic resonance imaging study in human subjects.

    Science.gov (United States)

    Pryor, K O; Root, J C; Mehta, M; Stern, E; Pan, H; Veselis, R A; Silbersweig, D A

    2015-07-01

    Subclinical doses of propofol produce anterograde amnesia, characterized by an early failure of memory consolidation. It is unknown how propofol affects the amygdala-dependent emotional memory system, which modulates consolidation in the hippocampus in response to emotional arousal and neurohumoral stress. We present an event-related functional magnetic resonance imaging study of the effects of propofol on the emotional memory system in human subjects. Thirty-five healthy subjects were randomized to receive propofol, at an estimated brain concentration of 0.90 μg ml(-1), or placebo. During drug infusion, emotionally arousing and neutral images were presented in a continuous recognition task, while blood-oxygen-level-dependent activation responses were acquired. After a drug-free interval of 2 h, subsequent memory for successfully encoded items was assessed. Imaging analysis was performed using statistical parametric mapping and behavioural analysis using signal detection models. Propofol had no effect on the stereotypical amygdalar response to emotional arousal, but caused marked suppression of the hippocampal response. Propofol caused memory performance to become uncoupled from amygdalar activation, but it remained correlated with activation in the posterior hippocampus, which decreased in proportion to amnesia. Propofol is relatively ineffective at suppressing amygdalar activation at sedative doses, but abolishes emotional modulation and causes amnesia via mechanisms that commonly involve hyporesponsiveness of the hippocampus. These findings raise the possibility that amygdala-dependent fear systems may remain intact even when a patient has diminished memory of events. This may be of clinical importance in the perioperative development of fear-based psychopathologies, such as post-traumatic stress disorder. NCT00504894. © The Author 2015. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions

  4. Markov counting and reward processes for analysing the performance of a complex system subject to random inspections

    International Nuclear Information System (INIS)

    Ruiz-Castro, Juan Eloy

    2016-01-01

    In this paper, a discrete complex reliability system subject to internal failures and external shocks, is modelled algorithmically. Two types of internal failure are considered: repairable and non-repairable. When a repairable failure occurs, the unit goes to corrective repair. In addition, the unit is subject to external shocks that may produce an aggravation of the internal degradation level, cumulative damage or extreme failure. When a damage threshold is reached, the unit must be removed. When a non-repairable failure occurs, the device is replaced by a new, identical one. The internal performance and the external damage are partitioned in performance levels. Random inspections are carried out. When an inspection takes place, the internal performance of the system and the damage caused by external shocks are observed and if necessary the unit is sent to preventive maintenance. If the inspection observes minor state for the internal performance and/or external damage, then these states remain in memory when the unit goes to corrective or preventive maintenance. Transient and stationary analyses are performed. Markov counting and reward processes are developed in computational form to analyse the performance and profitability of the system with and without preventive maintenance. These aspects are implemented computationally with Matlab. - Highlights: • A multi-state device is modelled in an algorithmic and computational form. • The performance is partitioned in multi-states and degradation levels. • Several types of failures with repair times according to degradation levels. • Preventive maintenance as response to random inspection is introduced. • The performance-profitable is analysed through Markov counting and reward processes.

  5. An additive matrix preconditioning method with application for domain decomposition and two-level matrix partitionings

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2010-01-01

    Roč. 5910, - (2010), s. 76-83 ISSN 0302-9743. [International Conference on Large-Scale Scientific Computations, LSSC 2009 /7./. Sozopol, 04.06.2009-08.06.2009] R&D Projects: GA AV ČR 1ET400300415 Institutional research plan: CEZ:AV0Z30860518 Keywords : additive matrix * condition number * domain decomposition Subject RIV: BA - General Mathematics www.springerlink.com

  6. Quality of Service-Driven Requirements Analyses for Component Composition: A Two-Level Grammar++ Approach

    National Research Council Canada - National Science Library

    Liu, Shih-Hsi; Cao, Fei; Bryant, Barrett R; Gray, Jeff; Raje, Rajeev R; Olson, Andrew M; Auguston, Mikhail

    2005-01-01

    .... When applied to Distributed Real-Time and Embedded (DRE) systems, which components to assemble and how to assemble them are determined not only from functional correctness criteria but also assurance of the system's quality of service (QoS...

  7. Subjective and objective image qualities: a comparison of sagittal T2 weighted spin-echo and turbo-spin-eco sequences in magnetic resonance imaging of the spine by use of a subjective ranking system

    Energy Technology Data Exchange (ETDEWEB)

    Goerres, G. [Institut fuer diagnostische Radiologie, Departement Radiologie, Universitaetskliniken, Kantonsspital Basel (Switzerland); Mader, I. [Radiologische Gemeinschaftspraxis Dres. Siems, Grossmann, Bayreuth (Germany); Proske, M. [Klinikum Rosenheim (Germany). Inst. fuer Diagnostische Radiologie

    1998-12-31

    We evaluated the subjective image impression of two different magnetic resonance (MR) sequences by using a subjective ranking system. This ranking system was based on 20 criteria describing several tissue characteristics such as the signal intensity of normal anatomical structures and the changes of signal intensities and shape of lesions as well as artefacts. MR of the vertebral spine was performed in 48 female and 52 male patients (mean age 44.8 years) referred consecutively for investigation of a back problem. Ninety-six pathologies were found in 82 patients. Sagittal and axial T1 weighted spin-echo before and after administration of Gadolinium (Gd-DOTA), and sagittal T2 weighted spin-echo (T2wSE) and Turbo-spin-echo (TSE) sequences were performed by means of surface coils. Using the subjective ranking system the sagittal T2wSE and sagittal TSE were compared. Both sequences were suitable for identification of normal anatomy and pathologic changes and there was no trend for increased detection of disease by one imaging sequence over the other. We found that sagittal TSE sequences can replace sagittal T2wSE sequences in spinal MR and that artefacts at the cervical and lumbar spine are less frequent using TSE, thus confirming previous studies. In this study, our ranking system reveiled, that there are differences between the subjective judgement of image qualities and objective measurement of SNR. However, this approach may not be helpful to compare two different MR sequences as it is limited to the anatomical area investigated and is time consuming. The subjective image impression, i.e. the quality of images, may not always be represented by physical parameters such as a signal-to-noise ratio (SNR), radiologists should try to define influences of image quality also by subjective parameters. (orig.)

  8. MRI pattern of arthritis in systemic lupus erythematosus: a comparative study with rheumatoid arthritis and healthy subjects

    Energy Technology Data Exchange (ETDEWEB)

    Tani, Chiara; Possemato, Niccolo; Delle Sedie, Andrea; Bombardieri, Stefano; Mosca, Marta [University of Pisa, Rheumatology Unit, Department of Clinical and Experimental Medicine, Pisa (Italy); D' aniello, Dario; Caramella, Davide [Radiology Unit, University of Pisa, Pisa (Italy)

    2014-10-24

    In this study we aimed to describe the magnetic resonance imaging (MRI) pattern of the distribution of bone marrow edema (BME) and joint erosion in hands and wrists of patients with systemic lupus erythematosus (SLE) with arthritis in comparison with rheumatoid arthritis (RA) and healthy subjects (H). SLE patients with arthritis (n = 50), patients with RA (n = 22), and H (n = 48) were enrolled. Every patient underwent a non-dominant hand (2nd-5th metacarpophalangeal joints) and wrist MRI without contrast injection with a low-field extremity dedicated 0.2-Tesla instrument. BME was observed in two SLE patients in the hand (4 %) and in 15 in the wrist (13 %) versus three (30 %), and 14 (63 %) RA patients. No BME was found in H. Erosions were observed in the hand in 24 SLE patients (48 %), 15 RA patients (68 %), and 9 H (18 %); in the wrist, in 41 (82 %) SLE, all RA and 47 (97 %) H. The cumulative erosive burden in SLE was significantly higher than in H (c = 0.002) but similar to RA patients. Joint involvement of the wrist in SLE is similar to RA and is not as rare as expected, as shown by the comparison with healthy subjects. On the contrary, the involvement of the hand in SLE is significantly lower compared to RA. (orig.)

  9. MRI pattern of arthritis in systemic lupus erythematosus: a comparative study with rheumatoid arthritis and healthy subjects

    International Nuclear Information System (INIS)

    Tani, Chiara; Possemato, Niccolo; Delle Sedie, Andrea; Bombardieri, Stefano; Mosca, Marta; D'aniello, Dario; Caramella, Davide

    2015-01-01

    In this study we aimed to describe the magnetic resonance imaging (MRI) pattern of the distribution of bone marrow edema (BME) and joint erosion in hands and wrists of patients with systemic lupus erythematosus (SLE) with arthritis in comparison with rheumatoid arthritis (RA) and healthy subjects (H). SLE patients with arthritis (n = 50), patients with RA (n = 22), and H (n = 48) were enrolled. Every patient underwent a non-dominant hand (2nd-5th metacarpophalangeal joints) and wrist MRI without contrast injection with a low-field extremity dedicated 0.2-Tesla instrument. BME was observed in two SLE patients in the hand (4 %) and in 15 in the wrist (13 %) versus three (30 %), and 14 (63 %) RA patients. No BME was found in H. Erosions were observed in the hand in 24 SLE patients (48 %), 15 RA patients (68 %), and 9 H (18 %); in the wrist, in 41 (82 %) SLE, all RA and 47 (97 %) H. The cumulative erosive burden in SLE was significantly higher than in H (c = 0.002) but similar to RA patients. Joint involvement of the wrist in SLE is similar to RA and is not as rare as expected, as shown by the comparison with healthy subjects. On the contrary, the involvement of the hand in SLE is significantly lower compared to RA. (orig.)

  10. Noninvasive verification of nasogastric tube placement using a magnet-tracking system: a pilot study in healthy subjects.

    Science.gov (United States)

    Bercik, Premysl; Schlageter, Vincent; Mauro, Marina; Rawlinson, John; Kucera, Pavel; Armstrong, David

    2005-01-01

    Fluoroscopic verification of nasogastric (NG) feeding tube placement is inconvenient and involves radiation exposure. We tested whether the position of an NG tube can be assessed reliably by a recently introduced magnet-tracking system. A small permanent magnet was attached at the end of an NG tube and its position was monitored using an external sensor array connected to a computer. NG tube trajectory, spontaneous movements of the magnet, and its position relative to the lower esophageal sphincter (LES) and xiphisternum were assessed in 22 healthy subjects and compared with esophageal manometry. In 12 subjects, localization of the magnet was also compared with fluoroscopy. Magnet-tracking displayed NG tube tip movement reproducibly as it moved vertically in the esophagus and then laterally into the stomach. Compared with manometry, the accuracy and sensitivity of magnet tracking for localization of the NG tube tip, above or below the diaphragm, were 100%. Compared with fluoroscopy, the accuracy of NG tube localization by magnet tracking was 100%. With the magnet in the stomach, but not in the esophagus or LES, low amplitude displacements at a frequency of 3 per minute, consistent with gastric slow wave activity, were observed. Magnet tracking allows accurate, real-time, 3-dimensional localization of an NG tube with respect to anatomic landmarks. Recorded motor patterns are indicative of the position of the NG tube. Magnet tracking may be a useful tool for bedside placement of nasogastric and enteral feeding tubes.

  11. Performance Evaluation of Waterproofing Membrane Systems Subject to the Concrete Joint Load Behavior of Below-Grade Concrete Structures

    Directory of Open Access Journals (Sweden)

    Jaeyoung Song

    2017-11-01

    Full Text Available Below-grade structures such as parking lots, underground subway tunnels, and basements are growing in scale and reaching deeper below-ground levels. In this type of environment, they become subject to higher water pressure. The concrete material of the structures is exposed to wet conditions for longer periods of time, which makes the proper adhesion of waterproofing membranes difficult. Joint movements from increased structural settlement, thermal expansion/shrinkage, and physical loads from external sources (e.g., vehicles make securing durable waterproofing challenging. While ASTM Guides, Korean Codes, and BS Practice Codes on below-grade waterproofing stress the importance of manufacturer specification for quality control, ensuring high quality waterproofing for the ever-changing scale of construction remains a challenge. This study proposes a new evaluation method and criteria which allow for the selection of waterproofing membranes based on specific performance attributes and workmanship. It subjects six different waterproofing membrane systems (installed on dry and wet surface conditioned mortar slab specimens with an artificial joint to different cyclic movement widths to 300 cycles in water to demonstrate that inadequate material properties and workmanship are key causes for leakages.

  12. Response localization of the pharmacological agents histamine and salbutamol along the respiratory system by forced oscillations in asthmatic subjects.

    Science.gov (United States)

    Wouters, E F; Polko, A H; Visser, B F

    1989-01-01

    The bronchodilating effect of 1 mg and 0.4 mg salbutamol on the impedance of the respiratory system was studied in 25 asthmatic subjects after histamine-induced bronchoconstriction. Histamine caused an increase of respiratory resistance (Rrs) at lower frequencies and a frequency dependence of Rrs. Respiratory reactance (Xrs) decreased at all frequencies after histamine challenge. These changes can be explained by peripheral airway obstruction. Impedance measurements performed 5 min after inhalation of 1 mg and 0.4 mg salbutamol showed a decrease of Rrs values at lower frequencies, a disappearance of the frequency dependence of Rrs, and a significant increase of Xrs values. No significant differences in absolute changes of Rrs and Xrs are observed between the salbutamol regimens. These changes after inhalation of salbutamol can be explained by supposing a predominant action on the peripheral airways.

  13. Two-Level Chebyshev Filter Based Complementary Subspace Method: Pushing the Envelope of Large-Scale Electronic Structure Calculations.

    Science.gov (United States)

    Banerjee, Amartya S; Lin, Lin; Suryanarayana, Phanish; Yang, Chao; Pask, John E

    2018-06-12

    We describe a novel iterative strategy for Kohn-Sham density functional theory calculations aimed at large systems (>1,000 electrons), applicable to metals and insulators alike. In lieu of explicit diagonalization of the Kohn-Sham Hamiltonian on every self-consistent field (SCF) iteration, we employ a two-level Chebyshev polynomial filter based complementary subspace strategy to (1) compute a set of vectors that span the occupied subspace of the Hamiltonian; (2) reduce subspace diagonalization to just partially occupied states; and (3) obtain those states in an efficient, scalable manner via an inner Chebyshev filter iteration. By reducing the necessary computation to just partially occupied states and obtaining these through an inner Chebyshev iteration, our approach reduces the cost of large metallic calculations significantly, while eliminating subspace diagonalization for insulating systems altogether. We describe the implementation of the method within the framework of the discontinuous Galerkin (DG) electronic structure method and show that this results in a computational scheme that can effectively tackle bulk and nano systems containing tens of thousands of electrons, with chemical accuracy, within a few minutes or less of wall clock time per SCF iteration on large-scale computing platforms. We anticipate that our method will be instrumental in pushing the envelope of large-scale ab initio molecular dynamics. As a demonstration of this, we simulate a bulk silicon system containing 8,000 atoms at finite temperature, and obtain an average SCF step wall time of 51 s on 34,560 processors; thus allowing us to carry out 1.0 ps of ab initio molecular dynamics in approximately 28 h (of wall time).

  14. Radiographic changes of the distal phalangeal tuft of the hands in subjects with systemic sclerosis. Systematic review.

    Science.gov (United States)

    Izquierdo, Yojhan Edilberto; Calvo Páramo, Enrique; Castañeda, Luisa María; Gómez, Sandra Viviana; Zambrano, Fernán Santiago

    To determine abnormal plain radiograph findings of the distal phalanx tuft of the hand (DPTH) associated with systemic sclerosis in adults. A systematic review was developed following the parameters of the PRISMA guidelines in databases: MEDLINE, EMBASE, BIREME, Scielo, Google Scholar and others including as primary outcomes alterations of DPTH (erosions, resorption, sclerosis and proliferation) detected by simple radiography in subjects with systemic sclerosis. The prevalence of radiographic findings was synthesized using the fixed effects model. The statistical associations were expressed in terms of relative risk or odds ratio with their respective confidence intervals and p values. Twenty-two observational studies were included; the prevalence of DPTH resorption was 28.3% (95% CI: 0.256-0.312; p < .001); I 2 =80.4%, the prevalence of calcinosis was 15.6% (95% CI: 0.113-0.210; p < .001); I 2 =0%. No study reported proliferation or erosions and only one study described sclerosis of DPTH in 5 individuals. Resorption and calcinosis of DPTH are the characteristic radiographic findings in patients with systemic sclerosis. However, new studies with greater methodological strength are needed to establish associations between these phenomena and their presence in other connective tissue diseases. Copyright © 2016 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

  15. Melnikov's criteria, parametric control of chaos, and stationary chaos occurrence in systems with asymmetric potential subjected to multiscale type excitation.

    Science.gov (United States)

    Kwuimy, C A Kitio; Nataraj, C; Litak, G

    2011-12-01

    We consider the problems of chaos and parametric control in nonlinear systems under an asymmetric potential subjected to a multiscale type excitation. The lower bound line for horseshoes chaos is analyzed using the Melnikov's criterion for a transition to permanent or transient nonperiodic motions, complement by the fractal or regular shape of the basin of attraction. Numerical simulations based on the basins of attraction, bifurcation diagrams, Poincaré sections, Lyapunov exponents, and phase portraits are used to show how stationary dissipative chaos occurs in the system. Our attention is focussed on the effects of the asymmetric potential term and the driven frequency. It is shown that the threshold amplitude ∣γ(c)∣ of the excitation decreases for small values of the driven frequency ω and increases for large values of ω. This threshold value decreases with the asymmetric parameter α and becomes constant for sufficiently large values of α. γ(c) has its maximum value for asymmetric load in comparison with the symmetric load. Finally, we apply the Melnikov theorem to the controlled system to explore the gain control parameter dependencies.

  16. Multi-objective optimal planning of the stand-alone microgrid system based on different benefit subjects

    International Nuclear Information System (INIS)

    Guo, Li; Wang, Nan; Lu, Hai; Li, Xialin; Wang, Chengshan

    2016-01-01

    As an important means to realize the energetic complementarity and improve the efficiency of renewable resources, the stand-alone microgrid (SAMG) system gains attention increasingly, especially in islands and remote areas. In this paper, considering the interest conflict of the distribution company and the distributed generation owner, a new multi-objective optimal planning model is formulated for medium voltage SAMG. Besides, to avoid the power constraint of distributed generation (DG) once the over-limit voltage occurs, a novel two-step power dispatch control method including the voltage regulation strategy is proposed, in which the absorption of distributed power by energy storage system (ESS) and the reactive power adjustment though its power control system are used to regulate voltage. The goal of this paper is to search the Pareto-optimal front of the site and capacity of DG as well as the contract price between both parties, and thus can provide effective references for practical planning of SAMG. Considering the high cost of ESS, the investment analysis of ESS is also discussed in the paper. - Highlights: • A multi-objective planning model based on different benefit subjects is proposed. • A two-step power dispatch method including the voltage regulation is proposed. • The economical efficiency of the proposed model is analyzed. • The effective reference for the stand-alone microgrid planning is provided.

  17. Design and Development of a Model to Simulate 0-G Treadmill Running Using the European Space Agency's Subject Loading System

    Science.gov (United States)

    Caldwell, E. C.; Cowley, M. S.; Scott-Pandorf, M. M.

    2010-01-01

    Develop a model that simulates a human running in 0 G using the European Space Agency s (ESA) Subject Loading System (SLS). The model provides ground reaction forces (GRF) based on speed and pull-down forces (PDF). DESIGN The theoretical basis for the Running Model was based on a simple spring-mass model. The dynamic properties of the spring-mass model express theoretical vertical GRF (GRFv) and shear GRF in the posterior-anterior direction (GRFsh) during running gait. ADAMs VIEW software was used to build the model, which has a pelvis, thigh segment, shank segment, and a spring foot (see Figure 1).the model s movement simulates the joint kinematics of a human running at Earth gravity with the aim of generating GRF data. DEVELOPMENT & VERIFICATION ESA provided parabolic flight data of subjects running while using the SLS, for further characterization of the model s GRF. Peak GRF data were fit to a linear regression line dependent on PDF and speed. Interpolation and extrapolation of the regression equation provided a theoretical data matrix, which is used to drive the model s motion equations. Verification of the model was conducted by running the model at 4 different speeds, with each speed accounting for 3 different PDF. The model s GRF data fell within a 1-standard-deviation boundary derived from the empirical ESA data. CONCLUSION The Running Model aids in conducting various simulations (potential scenarios include a fatigued runner or a powerful runner generating high loads at a fast cadence) to determine limitations for the T2 vibration isolation system (VIS) aboard the International Space Station. This model can predict how running with the ESA SLS affects the T2 VIS and may be used for other exercise analyses in the future.

  18. An Efficient Data Fingerprint Query Algorithm Based on Two-Leveled Bloom Filter

    OpenAIRE

    Bin Zhou; Rongbo Zhu; Ying Zhang; Linhui Cheng

    2013-01-01

    The function of the comparing fingerprints algorithm was to judge whether a new partitioned data chunk was in a storage system a decade ago.  At present, in the most de-duplication backup system the fingerprints of the big data chunks are huge and cannot be stored in the memory completely. The performance of the system is unavoidably retarded by data chunks accessing the storage system at the querying stage. Accordingly, a new query mechanism namely Two-stage Bloom Filter (TBF) mechanism...

  19. Fear of happiness predicts subjective and psychological well-being above the behavioral inhibition system (BIS and behavioral activation system (BAS model of personality

    Directory of Open Access Journals (Sweden)

    Murat Yildirim

    2018-03-01

    Full Text Available Fear of happiness is an important psychological construct and has a significant effect on life outcomes such as well-being. This study sought to examine whether fear of happiness could explain variance in subjective well-being and psychological well-being domains after controlling for Behavioral Inhibition System (BIS and Behavioral Activation System (BAS Model of Personality. A total of 243 participants (189 males and 54 females completed Fear of Happiness Scale, Positive-Negative Affect Schedule, Psychological Well-being Scales and BIS/BAS personality scales. In terms of correlational analyses, fear of happiness revealed significant negative correlations with positive affect, all domains of psychological well-being except purpose in life (autonomy, environmental mastery, personal growth, positive relations with others, and self-acceptance and BAS fun seeking dimension while a significant positive correlation was found with negative affect. With regard to hierarchical multiple regression analyses, fear of happiness accounted for a unique variance in both affective aspects of subjective well-being, namely positive and negative affect and three aspects of psychological well-being (autonomy, positive relations and self-acceptance after controlling for BIS/BAS personality model. These results suggested that fear of happiness is uniquely useful to both subjective and psychological well-being beyond the effect of the aspects of BIS/BAS personality.

  20. Controlled ultrafast transfer and stability degree of generalized coherent states of a kicked two-level ion

    Science.gov (United States)

    Chen, Hao; Kong, Chao; Hai, Wenhua

    2018-06-01

    We investigate quantum dynamics of a two-level ion trapped in the Lamb-Dicke regime of a δ -kicked optical lattice, based on the exact generalized coherent states rotated by a π / 2 pulse of Ramsey type experiment. The spatiotemporal evolutions of the spin-motion entangled states in different parameter regions are illustrated, and the parameter regions of different degrees of quantum stability described by the quantum fidelity are found. Time evolutions of the probability for the ion being in different pseudospin states reveal that the ultrafast entanglement generation and population transfers of the system can be analytically controlled by managing the laser pulses. The probability in an initially disentangled state shows periodic collapses (entanglement) and revivals (de-entanglement). Reduction of the stability degree results in enlarging the period of de-entanglement, while the instability and potential chaos will cause the sustained entanglement. The results could be justified experimentally in the existing setups and may be useful in engineering quantum dynamics for quantum information processing.

  1. Ordering policies of a deteriorating item in an EOQ model with backorder under two-level partial trade credit

    Science.gov (United States)

    Molamohamadi, Zohreh; Arshizadeh, Rahman; Ismail, Napsiah

    2015-05-01

    In the classical inventory model, it was assumed that the retailer must settle the accounts of the purchased items as soon as they are received. In practice, however, the supplier usually offers a full or partial delay period to the retailer to pay for the amount of the purchasing costs. In the partial trade credit contract, which is mostly applied to avoid non-payment risks, the retailer must pay for a portion of the purchased goods at the time of ordering and may delay settling the rest until the end of the predefined agreed upon period, so-called credit period. This paper assumes a two-level partial trade credit where both supplier and retailer offer a partial trade credit to their downstream members. The objective here is to determine the retailer's ordering policy of a deteriorating item by formulating his economic order quantity (EOQ) inventory system with backorder as a cost minimization problem. The sensitivity of the variables on different parameters has been also analyzed by applying numerical examples.

  2. Optimal Policies for Deteriorating Items with Maximum Lifetime and Two-Level Trade Credits

    Directory of Open Access Journals (Sweden)

    Nita H. Shah

    2014-01-01

    Full Text Available The retailer’s optimal policies are developed when the product has fixed lifetime and also the units in inventory are subject to deterioration at a constant rate. This study will be mainly applicable to pharmaceuticals, drugs, beverages, and dairy products, and so forth. To boost the demand, offering a credit period is considered as the promotional tool. The retailer passes credit period to the buyers which is received from the supplier. The objective is to maximize the total profit per unit time of the retailer with respect to optimal retail price of an item and purchase quantity during the optimal cycle time. The concavity of the total profit per unit time is exhibited using inventory parametric values. The sensitivity analysis is carried out to advise the decision maker to keep an eye on critical inventory parameters.

  3. Output Feedback Finite-Time Stabilization of Systems Subject to Hölder Disturbances via Continuous Fractional Sliding Modes

    Directory of Open Access Journals (Sweden)

    Aldo-Jonathan Muñoz-Vázquez

    2017-01-01

    Full Text Available The problem of designing a continuous control to guarantee finite-time tracking based on output feedback for a system subject to a Hölder disturbance has remained elusive. The main difficulty stems from the fact that such disturbance stands for a function that is continuous but not necessarily differentiable in any integer-order sense, yet it is fractional-order differentiable. This problem imposes a formidable challenge of practical interest in engineering because (i it is common that only partial access to the state is available and, then, output feedback is needed; (ii such disturbances are present in more realistic applications, suggesting a fractional-order controller; and (iii continuous robust control is a must in several control applications. Consequently, these stringent requirements demand a sound mathematical framework for designing a solution to this control problem. To estimate the full state in finite-time, a high-order sliding mode-based differentiator is considered. Then, a continuous fractional differintegral sliding mode is proposed to reject Hölder disturbances, as well as for uncertainties and unmodeled dynamics. Finally, a homogeneous closed-loop system is enforced by means of a continuous nominal control, assuring finite-time convergence. Numerical simulations are presented to show the reliability of the proposed method.

  4. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    International Nuclear Information System (INIS)

    Wang Canjun; Wei Qun; Mei Dongcheng

    2008-01-01

    The associated relaxation time T c and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T c and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ 1 increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ 3 , the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ 2 cannot affect the tumor cell numbers; The relaxation time T c is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ 1 and τ 3 enhance the related activity between two states at different time; However, τ 2 has no effect on the related activity between two states at different time

  5. Interleukin-6 levels in the central nervous system are negatively correlated with fat mass in overweight/obese subjects.

    Science.gov (United States)

    Stenlöf, Kaj; Wernstedt, Ingrid; Fjällman, Ted; Wallenius, Ville; Wallenius, Kristina; Jansson, John-Olov

    2003-09-01

    Recently, we demonstrated that intracerebroventricular injection of IL-6 increases energy expenditure and decreases body fat in rodents. Therefore, IL-6 may play a role in appetite and body weight control in the central nervous system. In the present study we evaluated cerebrospinal fluid (CSF) and serum IL-6 levels in humans in relation to body fat content and to CSF and serum levels of leptin. Thirty-two healthy overweight/obese male subjects with a body mass index range of 29.3-36.0 kg/m(2) were studied. Total and sc body fat were measured by dual energy x-ray absorptiometry and computed tomography, respectively. CSF IL-6 levels were in some individuals higher than serum IL-6 levels and correlated negatively with total body weight, sc and total body fat. In contrast, CSF leptin levels were 30-60 times lower than serum leptin levels and correlated positively with serum leptin, body weight, sc and total body fat. Furthermore, there was a negative correlation between CSF IL-6 and leptin. In conclusion, CSF IL-6 differs in many ways from CSF leptin. CSF IL-6 may be locally produced rather than serum derived, and body fat-regulating regions in the central nervous system may be exposed to insufficient IL-6 levels in more severe obesity.

  6. Associated relaxation time and the correlation function for a tumor cell growth system subjected to color noises

    Science.gov (United States)

    Wang, Can-Jun; Wei, Qun; Mei, Dong-Cheng

    2008-03-01

    The associated relaxation time T and the normalized correlation function C(s) for a tumor cell growth system subjected to color noises are investigated. Using the Novikov theorem and Fox approach, the steady probability distribution is obtained. Based on them, the expressions of T and C(s) are derived by means of projection operator method, in which the effects of the memory kernels of the correlation function are taken into account. Performing the numerical computations, it is found: (1) With the cross-correlation intensity |λ|, the additive noise intensity α and the multiplicative noise self-correlation time τ increasing, the tumor cell numbers can be restrained; And the cross-correlation time τ, the multiplicative noise intensity D can induce the tumor cell numbers increasing; However, the additive noise self-correlation time τ cannot affect the tumor cell numbers; The relaxation time T is a stochastic resonant phenomenon, and the distribution curves exhibit a single-maximum structure with D increasing. (2) The cross-correlation strength λ weakens the related activity between two states of the tumor cell numbers at different time, and enhances the stability of the tumor cell growth system in the steady state; On the contrast, τ and τ enhance the related activity between two states at different time; However, τ has no effect on the related activity between two states at different time.

  7. Switched Two-Level H∞ and Robust Fuzzy Learning Control of an Overhead Crane

    Directory of Open Access Journals (Sweden)

    Kao-Ting Hung

    2013-01-01

    Full Text Available Overhead cranes are typical dynamic systems which can be modeled as a combination of a nominal linear part and a highly nonlinear part. For such kind of systems, we propose a control scheme that deals with each part separately, yet ensures global Lyapunov stability. The former part is readily controllable by the H∞ PDC techniques, and the latter part is compensated by fuzzy mixture of affine constants, leaving the remaining unmodeled dynamics or modeling error under robust learning control using the Nelder-Mead simplex algorithm. Comparison with the adaptive fuzzy control method is given via simulation studies, and the validity of the proposed control scheme is demonstrated by experiments on a prototype crane system.

  8. Entanglement manipulation via Coulomb interaction in an optomechanical cavity assisted by two-level cold atoms

    Science.gov (United States)

    Wang, Jing; Tian, Xue-Dong; Liu, Yi-Mou; Cui, Cui-Li; Wu, Jin-Hui

    2018-06-01

    We investigate the stationary entanglement properties in a hybrid system consisting of an optical cavity, a mechanical resonator, a charged object, and an atomic ensemble. Numerical results show that this hybrid system exhibits three kinds of controllable bipartite entanglements in an experimentally accessible parameter regime with the help of the charged object. More importantly, it is viable to enhance on demand each bipartite entanglement at the expense of reducing others by modulating the Coulomb coupling strength. Last but not least, these bipartite entanglements seem more robust against on the environmental temperature for the positive Coulomb interaction.

  9. Two-level preconditioned conjugate gradient methods with applications to bubbly flow problems

    NARCIS (Netherlands)

    Tang, J.M.

    2008-01-01

    The Preconditioned Conjugate Gradient (PCG) method is one of the most popular iterative methods for solving large linear systems with a symmetric and positive semi-definite coefficient matrix. However, if the preconditioned coefficient matrix is ill-conditioned, the convergence of the PCG method

  10. Cross-Circulating Current Suppression Method for Parallel Three-Phase Two-Level Inverters

    DEFF Research Database (Denmark)

    Wei, Baoze; Guerrero, Josep M.; Guo, Xiaoqiang

    2015-01-01

    The parallel architecture is very popular for power inverters to increase the power level. This paper presents a method for the parallel operation of inverters in an ac-distributed system, to suppress the cross-circulating current based on virtual impedance without current-sharing bus...

  11. A TWO LEVEL ARCHITECTURE USING CONSENSUS METHOD FOR GLOBAL DECISION MAKING AGAINST DDoS ATTACKS

    Directory of Open Access Journals (Sweden)

    S.Seetha

    2010-06-01

    Full Text Available Distributed Denial of service is a major threat to the availability of internet services. Due to the distributed, large scale nature of the Internet makes DDoS (Distributed Denial-of-Service attacks stealthy and difficult to counter. Defense against Distributed Denial- of -Service attacks is one of the hardest security problems on the Internet. Recently these network attacks have been increasing. Therefore more effective countermeasures are required to counter the threat. This requirement has motivated us to propose a novel mechanism against DDoS attack. This paper presents the design details of a distributed defense mechanism against DDoS attack. In our approach, the egress routers of the intermediate network coordinate with each other to provide the information necessary to detect and respond to the attack. Thus, a detection system based on single site will have either high positive or high negative rates. Unlike the traditional IDSs (Intrusion Detection System this method has the potential to achieve high true positive ratio. This work has been done by using consensus algorithms for exchanging the information between the detection systems. So the overall detection time would be reduced for global decision making.

  12. Vertical dynamics of a single-span beam subjected to moving mass-suspended payload system with variable speeds

    Science.gov (United States)

    He, Wei

    2018-03-01

    This paper presents the vertical dynamics of a simply supported Euler-Bernoulli beam subjected to a moving mass-suspended payload system of variable velocities. A planar theoretical model of the moving mass-suspended payload system of variable speeds is developed based on several assumptions: the rope is massless and rigid, and its length keeps constant; the stiffness of the gantry beam is much greater than the supporting beam, and the gantry beam can be treated as a mass particle traveling along the supporting beam; the supporting beam is assumed as a simply supported Bernoulli-Euler beam. The model can be degenerated to consider two classical cases-the moving mass case and the moving payload case. The proposed model is verified using both numerical and experimental methods. To further investigate the effect of possible influential factors, numerical examples are conducted covering a range of parameters, such as variable speeds (acceleration or deceleration), mass ratios of the payload to the total moving load, and the pendulum lengths. The effect of beam flexibility on swing response of the payload is also investigated. It is shown that the effect of a variable speed is significant for the deflections of the beam. The accelerating movement tends to induce larger beam deflections, while the decelerating movement smaller ones. For accelerating or decelerating movements, the moving mass model may underestimate the deflections of the beam compared with the presented model; while for uniform motion, both the moving mass model and the moving mass-payload model lead to same beam responses. Furthermore, it is observed that the swing response of the payload is not sensitive to the stiffness of the beam for operational cases of a moving crane, thus a simple moving payload model can be employed in the swing control of the payload.

  13. A two-level real-time vision machine combining coarse and fine grained parallelism

    DEFF Research Database (Denmark)

    Jensen, Lars Baunegaard With; Kjær-Nielsen, Anders; Pauwels, Karl

    2010-01-01

    In this paper, we describe a real-time vision machine having a stereo camera as input generating visual information on two different levels of abstraction. The system provides visual low-level and mid-level information in terms of dense stereo and optical flow, egomotion, indicating areas...... a factor 90 and a reduction of latency of a factor 26 compared to processing on a single CPU--core. Since the vision machine provides generic visual information it can be used in many contexts. Currently it is used in a driver assistance context as well as in two robotic applications....

  14. Comparison of Helicopter Emergency Medical Services Transport Types and Delays on Patient Outcomes at Two Level I Trauma Centers.

    Science.gov (United States)

    Nolan, Brodie; Tien, Homer; Sawadsky, Bruce; Rizoli, Sandro; McFarlan, Amanda; Phillips, Andrea; Ackery, Alun

    2017-01-01

    Helicopter emergency medical services (HEMS) have become an engrained component of trauma systems. In Ontario, transportation for trauma patients is through one of three ways: scene call, modified scene call, or interfacility transfer. We hypothesize that differences exist between these types of transports in both patient demographics and patient outcomes. This study compares the characteristics of patients transported by each of these methods to two level 1 trauma centers and assesses for any impact on morbidity or mortality. As a secondary outcome reasons for delay were identified. A local trauma registry was used to identify and abstract data for all patients transported to two trauma centers by HEMS over a 36-month period. Further chart abstraction using the HEMS patient care reports was done to identify causes of delay during HEMS transport. During the study period HEMS transferred a total of 911 patients of which 139 were scene calls, 333 were modified scene calls and 439 were interfacility transfers. Scene calls had more patients with an ISS of less than 15 and had more patients discharged home from the ED. Modified scene calls had more patients with an ISS greater than 25. The most common delays that were considered modifiable included the sending physician doing a procedure, waiting to meet a land EMS crew, delays for diagnostic imaging and confirming disposition or destination. Differences exist between the types of transports done by HEMS for trauma patients. Many identified reasons for delay to HEMS transport are modifiable and have practical solutions. Future research should focus on solutions to identified delays to HEMS transport. Key words: helicopter emergency medical services; trauma; prehospital care; delays.

  15. Strategic production modeling for defective items with imperfect inspection process, rework, and sales return under two-level trade credit

    Directory of Open Access Journals (Sweden)

    Aditi Khanna

    2017-01-01

    Full Text Available Quality decisions are one of the major decisions in inventory management. It affects customer’s demand, loyalty and customer satisfaction and also inventory costs. Every manufacturing process is inherent to have some chance causes of variation which may lead to some defectives in the lot. So, in order to cater the customers with faultless products, an inspection process is inevitable, which may also be prone to errors. Thus for an operations manager, maintaining the quality of the lot and the screening process becomes a challenging task, when his objective is to determine the optimal order quantity for the inventory system. Besides these operational tasks, the goal is also to increase the customer base which eventually leads to higher profits. So, as a promotional tool, trade credit is being offered by both the retailer and supplier to their respective customers to encourage more frequent and higher volume purchases. Thus taking into account of these facts, a strategic production model is formulated here to study the combined effects of imperfect quality items, faulty inspection process, rework process, sales return under two level trade credit. The present study is a general framework for many articles and classical EPQ model. An analytical method is employed which jointly optimizes the retailer’s credit period and order quantity, so as to maximize the expected total profit per unit time. To study the behavior and application of the model, a numerical example has been cited and a comprehensive sensitivity analysis has been performed. The model can be widely applicable in manufacturing industries like textile, footwear, plastics, electronics, furniture etc.

  16. On the Performance Optimization of Two-Level Three-Phase Grid-Feeding Voltage-Source Inverters

    Directory of Open Access Journals (Sweden)

    Issam A. Smadi

    2018-02-01

    Full Text Available The performance optimization of the two-level, three-phase, grid-feeding, voltage-source inverter (VSI is studied in this paper, which adopts an online adaptive switching frequency algorithm (OASF. A new degree of freedom has been added to the employed OASF algorithm for optimal selection of the weighting factor and overall system optimization design. Toward that end, a full mathematical formulation, including the impact of the coupling inductor and the controller response time, is presented. At first, the weighting factor is selected to favor the switching losses, and the controller gains are optimized by minimizing the integral time-weighted absolute error (ITAE of the output active and reactive power. Different loading and ambient temperature conditions are considered to validate the optimized controller and its fast response through online field programmable gate array (FPGA-in-the-loop. Then, the weighting factor is optimally selected to reduce the cost of the L-filter and the heat-sink. An optimization problem to minimize the cost design at the worst case of loading condition for grid-feeding VSI is formulated. The results from this optimization problem are the filter inductance, the thermal resistance of the heat-sink, and the optimal switching frequency with the optimal weighting factor. The VSI test-bed using the optimized parameters is used to verify the proposed work experimentally. Adopting the OASF algorithm that employs the optimal weighting factor for grid-feeding VSI, the percentages of the reductions in the slope of the steady state junction temperature profile compared to fixed frequencies of 10 kHz, 14.434 kHz, and 20 kHz are about 6%, 30%, and 18%, respectively.

  17. NT-pro-BNP during hypoglycemia and hypoxemia in normal subjects: impact of renin-angiotensin system activity

    DEFF Research Database (Denmark)

    Due-Andersen, R; Pedersen-Bjergaard, U; Høi-Hansen, T

    2008-01-01

    subjects with high-RAS activity and 10 subjects with low-RAS activity (age 26 +/- 1 yr; mean +/- SE) were studied in a single-blinded, randomized, counterbalanced, crossover study on three occasions separated by at least 3 wk: 1) hypoglycemia (mean nadir plasma glucose 2.7 +/- 0.5 mmol/l), 2) hypoxemia...

  18. Direct Power Control for Three-Phase Two-Level Voltage-Source Rectifiers Based on Extended-State Observation

    DEFF Research Database (Denmark)

    Song, Zhanfeng; Tian, Yanjun; Yan, Zhuo

    2016-01-01

    This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent characte......This paper proposed a direct power control strategy for three-phase two-level voltage-source rectifiers based on extended-state observation. Active and reactive powers are directly regulated in the stationary reference frame. Similar to the family of predictive controllers whose inherent...

  19. Peak load demand forecasting using two-level discrete wavelet decomposition and neural network algorithm

    Science.gov (United States)

    Bunnoon, Pituk; Chalermyanont, Kusumal; Limsakul, Chusak

    2010-02-01

    This paper proposed the discrete transform and neural network algorithms to obtain the monthly peak load demand in mid term load forecasting. The mother wavelet daubechies2 (db2) is employed to decomposed, high pass filter and low pass filter signals from the original signal before using feed forward back propagation neural network to determine the forecasting results. The historical data records in 1997-2007 of Electricity Generating Authority of Thailand (EGAT) is used as reference. In this study, historical information of peak load demand(MW), mean temperature(Tmean), consumer price index (CPI), and industrial index (economic:IDI) are used as feature inputs of the network. The experimental results show that the Mean Absolute Percentage Error (MAPE) is approximately 4.32%. This forecasting results can be used for fuel planning and unit commitment of the power system in the future.

  20. Fabrication of a two-level tumor bone repair biomaterial based on a rapid prototyping technique

    Energy Technology Data Exchange (ETDEWEB)

    Kai He; Yan Yongnian; Zhang Renji; Wang Xiaohong [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education and Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Wang Xinluan; Madhukar, Kumta Shekhar; Qin Ling [Department of Orthoapedics and Traumatology, The Chinese University of Hong Kong. Shatin, NT (Hong Kong)], E-mail: wangxiaohong@tsinghua.edu.cn, E-mail: kumta@cuhk.edu.hk, E-mail: qin@ort.cuhk.edu.hk

    2009-06-01

    After the removal of the giant cell tumor (GCT) of bone, it is necessary to fill the defects with adequate biomaterials. A new functional bone repair material with both stimulating osteoblast growth and inhibiting osteoclast activity has been developed with phosphorylated chitosan (P-chitosan) and disodium (1 {yields} 4)-2-deoxy-2-sulfoamino-{beta}-D-glucopyranuronan (S-chitosan) as the additives of poly(lactic acid-co-glycolic acid) (PLGA)/calcium phosphate (TCP) scaffolds based on a double-nozzle low-temperature deposition manufacturing technique. A computer-assisted design model was used and the optimal fabrication parameters were determined through the manipulation of a pure PLGA/TCP system. The microscopic structures, water absorbability and mechanical properties of the samples with different P-chitosan and S-chitosan concentrations were characterized correspondingly. The results suggested that this unique composite porous scaffold material is a potential candidate for the repair of large bone defects after a surgical removal of GCT.

  1. Controlled cross-over study in normal subjects of naloxone-preceding-lactate infusions; respiratory and subjective responses: relationship to endogenous opioid system, suffocation false alarm theory and childhood parental loss.

    Science.gov (United States)

    Preter, M; Lee, S H; Petkova, E; Vannucci, M; Kim, S; Klein, D F

    2011-02-01

    The expanded suffocation false alarm theory (SFA) hypothesizes that dysfunction in endogenous opioidergic regulation increases sensitivity to CO2, separation distress and panic attacks. In panic disorder (PD) patients, both spontaneous clinical panics and lactate-induced panics markedly increase tidal volume (TV), whereas normals have a lesser effect, possibly due to their intact endogenous opioid system. We hypothesized that impairing the opioidergic system by naloxone could make normal controls parallel PD patients' response when lactate challenged. Whether actual separations and losses during childhood (childhood parental loss, CPL) affected naloxone-induced respiratory contrasts was explored. Subjective panic-like symptoms were analyzed although pilot work indicated that the subjective aspect of anxious panic was not well modeled by this specific protocol. Randomized cross-over sequences of intravenous naloxone (2 mg/kg) followed by lactate (10 mg/kg), or saline followed by lactate, were given to 25 volunteers. Respiratory physiology was objectively recorded by the LifeShirt. Subjective symptomatology was also recorded. Impairment of the endogenous opioid system by naloxone accentuates TV and symptomatic response to lactate. This interaction is substantially lessened by CPL. Opioidergic dysregulation may underlie respiratory pathophysiology and suffocation sensitivity in PD. Comparing specific anti-panic medications with ineffective anti-panic agents (e.g. propranolol) can test the specificity of the naloxone+lactate model. A screen for putative anti-panic agents and a new pharmacotherapeutic approach are suggested. Heuristically, the experimental unveiling of the endogenous opioid system impairing effects of CPL and separation in normal adults opens a new experimental, investigatory area.

  2. Controlled cross-over study in normal subjects of naloxone-preceding-lactate infusions; respiratory and subjective responses: relationship to endogenous opioid system, suffocation false alarm theory and childhood parental loss

    Science.gov (United States)

    Preter, M.; Lee, S. H.; Petkova, E.; Vannucci, M.; Kim, S.; Klein, D. F.

    2015-01-01

    Background The expanded suffocation false alarm theory (SFA) hypothesizes that dysfunction in endogenous opioidergic regulation increases sensitivity to CO2, separation distress and panic attacks. In panic disorder (PD) patients, both spontaneous clinical panics and lactate-induced panics markedly increase tidal volume (TV), whereas normals have a lesser effect, possibly due to their intact endogenous opioid system. We hypothesized that impairing the opioidergic system by naloxone could make normal controls parallel PD patients' response when lactate challenged. Whether actual separations and losses during childhood (childhood parental loss, CPL) affected naloxone-induced respiratory contrasts was explored. Subjective panic-like symptoms were analyzed although pilot work indicated that the subjective aspect of anxious panic was not well modeled by this specific protocol. Method Randomized cross-over sequences of intravenous naloxone (2 mg/kg) followed by lactate (10 mg/kg), or saline followed by lactate, were given to 25 volunteers. Respiratory physiology was objectively recorded by the LifeShirt. Subjective symptomatology was also recorded. Results Impairment of the endogenous opioid system by naloxone accentuates TV and symptomatic response to lactate. This interaction is substantially lessened by CPL. Conclusions Opioidergic dysregulation may underlie respiratory pathophysiology and suffocation sensitivity in PD. Comparing specific anti-panic medications with ineffective anti-panic agents (e.g. propranolol) can test the specificity of the naloxone + lactate model. A screen for putative anti-panic agents and a new pharmacotherapeutic approach are suggested. Heuristically, the experimental unveiling of the endogenous opioid system impairing effects of CPL and separation in normal adults opens a new experimental, investigatory area. PMID:20444308

  3. Objective and subjective comparison of standard 2-D and fully 3-D reconstructed data on a PET/CT system.

    Science.gov (United States)

    Strobel, Klaus; Rüdy, Matthias; Treyer, Valerie; Veit-Haibach, Patrick; Burger, Cyrill; Hany, Thomas F

    2007-07-01

    The relative advantage of fully 3-D versus 2-D mode for whole-body imaging is currently the focus of considerable expert debate. The nature of 3-D PET acquisition for FDG PET/CT theoretically allows a shorter scan time and improved efficiency of FDG use than in the standard 2-D acquisition. We therefore objectively and subjectively compared standard 2-D and fully 3-D reconstructed data for FDG PET/CT on a research PET/CT system. In a total of 36 patients (mean 58.9 years, range 17.3-78.9 years; 21 male, 15 female) referred for known or suspected malignancy, FDG PET/CT was performed using a research PET/CT system with advanced detector technology with improved sensitivity and spatial resolution. After 45 min uptake, a low-dose CT (40 mAs) from head to thigh was performed followed by 2-D PET (emission 3 min per field) and 3-D PET (emission 1.5 min per field) with both seven slices overlap to cover the identical anatomical region. Acquisition time was therefore 50% less (seven fields; 21 min vs. 10.5 min). PET data was acquired in a randomized fashion, so in 50% of the cases 2-D data was acquired first. CT data was used for attenuation correction. 2-D (OSEM) and 3-D PET images were iteratively reconstructed. Subjective analysis of 2-D and 3-D images was performed by two readers in a blinded, randomized fashion evaluating the following criteria: sharpness of organs (liver, chest wall/lung), overall image quality and detectability and dignity of each identified lesion. Objective analysis of PET data was investigated measuring maximum standard uptake value with lean body mass (SUV(max,LBM)) of identified lesions. On average, per patient, the SUV(max) was 7.86 (SD 7.79) for 2-D and 6.96 (SD 5.19) for 3-D. On a lesion basis, the average SUV(max) was 7.65 (SD 7.79) for 2-D and 6.75 (SD 5.89) for 3-D. The absolute difference on a paired t-test of SUV 3-D-2-D based on each measured lesion was significant with an average of -0.956 (P=0.002) and an average of -0.884 on a

  4. Coherent effects on two-photon correlation and directional emission of two two-level atoms

    International Nuclear Information System (INIS)

    Ooi, C. H. Raymond; Kim, Byung-Gyu; Lee, Hai-Woong

    2007-01-01

    Sub- and superradiant dynamics of spontaneously decaying atoms are manifestations of collective many-body systems. We study the internal dynamics and the radiation properties of two atoms in free space. Interesting results are obtained when the atoms are separated by less than half a wavelength of the atomic transition, where the dipole-dipole interaction gives rise to new coherent effects, such as (a) coherence between two intermediate collective states, (b) oscillations in the two-photon correlation G (2) , (c) emission of two photons by one atom, and (d) the loss of directional correlation. We compare the population dynamics during the two-photon emission process with the dynamics of single-photon emission in the cases of a Λ and a V scheme. We compute the temporal correlation and angular correlation of two successively emitted photons using the G (2) for different values of atomic separation. We find antibunching when the atomic separation is a quarter wavelength λ/4. Oscillations in the temporal correlation provide a useful feature for measuring subwavelength atomic separation. Strong directional correlation between two emitted photons is found for atomic separation larger than a wavelength. We also compare the directionality of a photon spontaneously emitted by the two atoms prepared in phased-symmetric and phased-antisymmetric entangled states vertical bar ±> k 0 =e ik 0 ·r 1 vertical bar a 1 ,b 2 >±e ik 0 ·r 2 vertical bar b 1 ,a 2 > by a laser pulse with wave vector k 0 . Photon emission is directionally suppressed along k 0 for the phased-antisymmetric state. The directionality ceases for interatomic distances less than λ/2

  5. Fractures of the talus: experience of two level 1 trauma centers.

    Science.gov (United States)

    Elgafy, H; Ebraheim, N A; Tile, M; Stephen, D; Kase, J

    2000-12-01

    Fifty-eight patients with 60 talar fractures were retrospectively reviewed. There were 39 men and 19 women. The age average was 32 (range, 14-74). Eighty six percent of the patients had multiple injuries. The most common mechanism of injury was a motor vehicle accident. Twenty-seven (45%) of the fractures were neck, 22 (36.7%) process, and 11 (18.3%) body. Forty-eight fractures had operative treatment and 12 had non-operative management. The average follow-up period was 30 months (range, 24-65). Thirty-two fractures (53.3%) developed subtalar arthritis. Two patients had subsequent subtalar fusion. Fifteen fractures (25%) developed ankle arthritis. None of these patients required ankle fusion. Fractures of the body of the talus were associated with the highest incidence of degenerative joint disease of both the subtalar and ankle joints. Ten fractures (16.6%) developed avascular necrosis (AVN), only one of which had subsequent slight collapse. Avascular necrosis occurred mostly after Hawkins Type 3 and 2 fractures of the talar neck. Three rating scores were used in this series to assess the outcome: the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score, Maryland Foot Score, and Hawkins Evaluation Criteria. The outcome was different with every rating system. However, the outcome with AOFAS Ankle-Hindfoot Score and Hawkins Evaluation Criteria were almost equivalent. Assessment with the three rating scores showed that the process fractures had the best results followed by the neck and then the body fractures.

  6. Aerobic exercise improves quality of life, psychological well-being and systemic inflammation in subjects with Alzheimer's disease.

    Science.gov (United States)

    Abd El-Kader, Shehab M; Al-Jiffri, Osama H

    2016-12-01

    Alzheimer's disease has a destructive drawbacks on the patient and his/her entire family as this disease badly af fects the behavior, cognition and abilities to do activities of daily living (ADL). The physical and mental benefits of exercise are widely known but seldom available to persons suffering from Alzheimer's disease. The aim of this study was to measure quality of life, systemic inflammation and psychological well-being response to aerobic exercises in Alzheimer's. Forty Alzheimer elderly subjects were enrolled in two groups; the first group received treadmill aerobic exercise, while the second group was considered as a control group and received no training intervention for two months. Assessment of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), Rosenberg Self-Esteem Scale (RSES),Beck Depression Inventory (BDI), Profile of Mood States(POMS) and SF-36 health quality of life (SF-36 HRQL) were taken before and at the end of the study. There was a 25.2%, 19.4%, 23.5%, 21.3%, 17.7% , 11.7%, 12.5% and 10.1 % reduction in mean values of TNF-α, IL-6, BDI, POMS, health transition SF-36 subscale, bodily pain SF-36 subscale, role functioning: emotional SF-36 subscale and mental health SF-36 subscale respectively in addition to 15.7%, 13.1%, 12.6%, 11.1%, 13.2% and 11.2 % increase in mean values of RSES, physical functioning SF-36 subscale, role functioning:physical SF-36 subscale, general health SF-36 subscale, Vitality SF-36 subscale and Social functioning SF-36 subscale respectively in group (A) received aerobic exercise training, so that there was a significant reduction in the mean values of TNF-α, IL-6, BDI & POMS and increase in the mean values of SF-36 HRQL subscale scores, RSES in group (A) as a result of aerobic exercise training, while the results of group (B) who received no training intervention were not significant. Also, there were significant differences between mean levels of the investigated parameters in group (A) and group (B) at

  7. Analytical Design of Passive LCL Filter for Three-phase Two-level Power Factor Correction Rectifiers

    DEFF Research Database (Denmark)

    Kouchaki, Alireza; Nymand, Morten

    2017-01-01

    This paper proposes a comprehensive analytical LCL filter design method for three-phase two-level power factor correction rectifiers (PFCs). The high frequency converter current ripple generates the high frequency current harmonics that need to be attenuated with respect to the grid standards...

  8. SYSTEM-COGNITIVE MODEL OF FORECASTING THE DEVELOPMENT OF DIVERSIFIED AGRO-INDUSTRIAL CORPORATIONS. PART I. COGNITIVE STRUCTURING AND FORMALIZATION OF THE SUBJECT AREA

    OpenAIRE

    Lutsenko Y. V.; Loyko V. I.; Baranovskaya T. P.; Makarevich O. A.

    2015-01-01

    In this article, in accordance with the methodology of the Automated system-cognitive analysis (ASCanalysis), we examine the implementation of the 1st and 2nd stages of ASC-analysis: cognitive structuring and formalization of the subject area. At the stage of cognitive structurization of subject area, researchers decide what to consider as the object of modeling, the factors affecting it and the results of their actions. In accordance with the results of the cognitive structurization, we prep...

  9. Theoretical analysis of the multiple resonances for many-level spin systems. The four-level spin system of s electron ions subjected to strong microwave fields

    International Nuclear Information System (INIS)

    Popescu, F.F.; Marica, F.

    1994-01-01

    The analytic steady state solutions of master equation for the density matrix of a multilevel spin system in dilute paramagnetic crystals at high temperature, subjected to strong microwave fields, are discussed. These solutions enable to obtain the populations of the levels, and the microwave powers absorbed or emitted by the crystal, in the presence of one, two or more microwave fields. A detailed theoretical study of the maser effects for s electron ions with nuclear spin one-half is carried out. In the case of three frequency correlated strong fields, when 'the spectroscopic' bridge conditions are fulfilled, sensitive detections, or high efficient generations of microwaves of frequency higher than those of the pumping fields are predicted. (author) 16 figs., 16 refs

  10. SUBJECT INDEX

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    granulite belt, India: structural and petrochemical evidences attesting to their relict nature. 337. Earth systems. Earth support systems: Threatened? Why? What can we do? 269. Earthquake source. Earthquake source model using strong motion dis- placement as response of finite elastic media. 9. Eastern Dharwar Craton.

  11. Clinical evaluation of an allogeneic bone matrix containing viable osteogenic cells in patients undergoing one- and two-level posterolateral lumbar arthrodesis with decompressive laminectomy.

    Science.gov (United States)

    Musante, David B; Firtha, Michael E; Atkinson, Brent L; Hahn, Rebekah; Ryaby, James T; Linovitz, Raymond J

    2016-05-27

    Trinity Evolution® cellular bone allograft (TE) possesses the osteogenic, osteoinductive, and osteoconductive elements essential for bone healing. The purpose of this study is to evaluate the radiographic and clinical outcomes when TE is used as a graft extender in combination with locally derived bone in one- and two-level instrumented lumbar posterolateral arthrodeses. In this retrospective evaluation, a consecutive series of subject charts that had posterolateral arthrodesis with TE and a 12-month radiographic follow-up were evaluated. All subjects were diagnosed with degenerative disc disease, radiculopathy, stenosis, and decreased disc height. At 2 weeks and at 3 and 12 months, plain radiographs were performed and the subject's back and leg pain (VAS) was recorded. An evaluation of fusion status was performed at 12 months. The population consisted of 43 subjects and 47 arthrodeses. At 12 months, a fusion rate of 90.7 % of subjects and 89.4 % of surgical levels was observed. High-risk subjects (e.g., diabetes, tobacco use, etc.) had fusion rates comparable to normal patients. Compared with the preoperative leg or back pain level, the postoperative pain levels were significantly (p < 0.0001) improved at every time point. There were no adverse events attributable to TE. Fusion rates using TE were higher than or comparable to fusion rates with autologous iliac crest bone graft that have been reported in the recent literature for posterolateral fusion procedures, and TE fusion rates were not adversely affected by several high-risk patient factors. The positive results provide confidence that TE can safely replace autologous iliac crest bone graft when used as a bone graft extender in combination with locally derived bone in the setting of posterolateral lumbar arthrodesis in patients with or without risk factors for compromised bone healing. Because of the retrospective nature of this study, the trial was not registered.

  12. On the structure of the master equation for a two-level system coupled to a thermal bath

    International Nuclear Information System (INIS)

    Vega, Inés de

    2015-01-01

    We derive a master equation from the exact stochastic Liouville–von-Neumann (SLN) equation (Stockburger and Grabert 2002 Phys. Rev. Lett. 88 170407). The latter depends on two correlated noises and describes exactly the dynamics of an oscillator (which can be either harmonic or present an anharmonicity) coupled to an environment at thermal equilibrium. The newly derived master equation is obtained by performing analytically the average over different noise trajectories. It is found to have a complex hierarchical structure that might be helpful to explain the convergence problems occurring when performing numerically the stochastic average of trajectories given by the SLN equation (Koch et al 2008 Phys. Rev. Lett. 100 230402, Koch 2010 PhD thesis Fakultät Mathematik und Naturwissenschaften der Technischen Universitat Dresden). (paper)

  13. On the structure of the master equation for a two-level system coupled to a thermal bath

    Science.gov (United States)

    de Vega, Inés

    2015-04-01

    We derive a master equation from the exact stochastic Liouville-von-Neumann (SLN) equation (Stockburger and Grabert 2002 Phys. Rev. Lett. 88 170407). The latter depends on two correlated noises and describes exactly the dynamics of an oscillator (which can be either harmonic or present an anharmonicity) coupled to an environment at thermal equilibrium. The newly derived master equation is obtained by performing analytically the average over different noise trajectories. It is found to have a complex hierarchical structure that might be helpful to explain the convergence problems occurring when performing numerically the stochastic average of trajectories given by the SLN equation (Koch et al 2008 Phys. Rev. Lett. 100 230402, Koch 2010 PhD thesis Fakultät Mathematik und Naturwissenschaften der Technischen Universitat Dresden).

  14. Retailer's inventory system in a two-level trade credit financing with selling price discount and partial order cancelations

    Science.gov (United States)

    Thangam, A.

    2015-06-01

    In today's fast marketing over the Internet or online, many retailers want to trade at the same time and change their marketing strategy to attract more customers. Some of the customers may decide to cancel their orders partially with a retailer due to various reasons such as increase in customer's waiting time, loss of customer's goodwill on retailer's business, attractive promotional schemes offered by other retailers etc. Even though there is a lag in trading and order cancelation, this paper attempts to develop the retailer's inventory model with the effect of order cancelations during advance sales period. The retailer announces a price discount program during advance sales period to promote his sales and also he offers trade credit financing during the sales periods. The retailer availing trade credit period from his supplier offers a permissible delay period to his customers. The customer who gets an item has allowed paying on or before the permissible delay period which is accounted from the buying time rather than the start period of inventory sales. This accounts for significant changes in the calculations of interest payable and interest earned by the retailer. The retailer's total cost is minimized so as to find out the optimal replenishment cycle time and price discount policies through a solution procedure. The results derived in mathematical theorems are implemented in numerical examples and sensitivity analyses on several inventory parameters are obtained.

  15. Retailer's inventory system in a two-level trade credit financing with selling price discount and partial order cancellations

    Science.gov (United States)

    Thangam, A.

    2014-02-01

    In today's fast marketing over the Internet or online, many retailers want to trade at the same time and change their marketing strategy to attract more customers. Some of the customers may decide to cancel their orders partially with a retailer due to various reasons such as increase in customer's waiting time, loss of customer's goodwill on retailer's business, and attractive promotional schemes offered by other retailers. Even though there is a lag in trading and order cancellation, this paper attempts to develop the retailer's inventory model with the effect of order cancellations during advance sales period. The retailer announces a price discount program during advance sales period to promote his sales and also offers trade credit financing during the sales periods. The retailer availing trade credit period from his supplier offers a permissible delay period to his customers. The customer who gets an item is allowed to pay on or before the permissible delay period which is accounted from the buying time rather than from the start period of inventory sales. This accounts for significant changes in the calculations of interest payable and interest earned by the retailer. The retailer's total cost is minimized so as to find out the optimal replenishment cycle time and price discount policies through a solution procedure. The results derived in mathematical theorems are implemented in numerical examples, and sensitivity analyses on several inventory parameters are obtained.

  16. Role of spontaneous emission through operating transition in probe-field spectroscopy of two-level systems

    Energy Technology Data Exchange (ETDEWEB)

    Saprykin, E. G. [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation); Chernenko, A. A., E-mail: chernen@isp.nsc.ru [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Shalagin, A. M. [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation)

    2016-08-15

    Analytical and numerical investigations are carried out of the effect of spontaneous decay through operating transition on the shape of a resonance in the work of a probe field under a strong field applied to the transition. A narrow nonlinear resonance arising on transitions with long-living lower level in the work of a probe field can manifest itself in the form of a traditional minimum and a peak as a function of the first Einstein coefficient for the operating transition. The transformation of the resonance from a minimum to a peak is attributed to the specific character of relaxation of lower-level population beatings on a closed or almost closed transition (the decay of the upper level occurs completely or almost completely through the operating transition).

  17. Effects of quasiparticle tunnelling in a circuit-QED realization of a strongly driven two-level system

    International Nuclear Information System (INIS)

    Leppäkangas, J; De Graaf, S E; Adamyan, A; Fogelström, M; Danilov, A V; Kubatkin, S E; Johansson, G; Lindström, T

    2013-01-01

    We experimentally and theoretically study the frequency shift of a driven cavity coupled to a superconducting charge qubit. In addition to previous studies, here we also consider drive strengths large enough to energetically allow for quasiparticle creation. Quasiparticle tunnelling leads to the inclusion of more than two charge states in the dynamics. To explain the observed effects, we develop a master equation for the microwave dressed charge states, including quasiparticle tunnelling. A bimodal behaviour of the frequency shift as a function of gate voltage can be used for sensitive charge detection. However, at weak drives, the charge sensitivity is significantly reduced by nonequilibrium quasiparticles, which induce transitions to a non-sensitive state. Unexpectedly, at high-enough drives, the quasiparticle tunnelling enables a very fast relaxation channel to the sensitive state. In this regime, the charge sensitivity is thus robust against externally injected quasiparticles and the desired dynamics prevail over a broad range of temperatures. We find very good agreement between the theory and experiment over a wide range of drive strengths and temperatures. (paper)

  18. Observation of the widening and shifting of EIT windows in a quasi-degenerate two-level atomic system

    International Nuclear Information System (INIS)

    Dong Yabin; Zhang Junxiang; Wang Haihong; Gao Jiangrui

    2006-01-01

    Widening and shifting the EIT windows in a closed transition F e = 2 ↔ F g = 3 driven by linearly polarized coupling lights and probed by circularly polarized lights are observed in Cs vapour. It is shown that by increasing the strength of magnetic field i.e. Zeeman splitting in the upper and lower levels, the electromagnetically induced transparency window is divided into two windows and the EIT maxima are shifted away from the zero detuning. In the contrast, if the strength of the magnetic field is fixed and the Rabi frequency of coupling beam is increased, the two EIT windows become wider, and the gap between the two EIT windows becomes smaller and smaller. These effects are also theoretically discussed and they are qualitatively in agreement with the theoretical results

  19. The reliability and validity of subjective notational analysis in comparison to global positioning system tracking to assess athlete movement patterns.

    Science.gov (United States)

    Doğramac, Sera N; Watsford, Mark L; Murphy, Aron J

    2011-03-01

    Subjective notational analysis can be used to track players and analyse movement patterns during match-play of team sports such as futsal. The purpose of this study was to establish the validity and reliability of the Event Recorder for subjective notational analysis. A course was designed, replicating ten minutes of futsal match-play movement patterns, where ten participants undertook the course. The course allowed a comparison of data derived from subjective notational analysis, to the known distances of the course, and to GPS data. The study analysed six locomotor activity categories, focusing on total distance covered, total duration of activities and total frequency of activities. The values between the known measurements and the Event Recorder were similar, whereas the majority of significant differences were found between the Event Recorder and GPS values. The reliability of subjective notational analysis was established with all ten participants being analysed on two occasions, as well as analysing five random futsal players twice during match-play. Subjective notational analysis is a valid and reliable method of tracking player movements, and may be a preferred and more effective method than GPS, particularly for indoor sports such as futsal, and field sports where short distances and changes in direction are observed.

  20. SUBJECT INDEX

    Indian Academy of Sciences (India)

    R.Narasimhan(krishtel emaging)1461 1996 Oct 15 13:05:22

    bian Pacific Ocean and its relationship with the wind field using .... Electron spin resonance dating of fault gouge from ... impact. Assimilation of IRS-P4 (MSMR) meteorological data in the NCMRWF global data ... mobile auroral current systems.

  1. SUBJECT INDEX

    Indian Academy of Sciences (India)

    (Afyon-Sandıklı) geothermal systems, SW Turkey 1081. Microtremor measurements ... Analysis of carbon dioxide, water vapour and energy fluxes over an Indian ... Petrological and geochemical characteristics of Paleo- proterozoic ultramafic ...

  2. PSCAD modeling of a two-level space vector pulse width modulation algorithm for power electronics education

    Directory of Open Access Journals (Sweden)

    Ahmet Mete Vural

    2016-09-01

    Full Text Available This paper presents the design details of a two-level space vector pulse width modulation algorithm in PSCAD that is able to generate pulses for three-phase two-level DC/AC converters with two different switching patterns. The presented FORTRAN code is generic and can be easily modified to meet many other kinds of space vector modulation strategies. The code is also editable for hardware programming. The new component is tested and verified by comparing its output as six gating signals with those of a similar component in MATLAB library. Moreover the component is used to generate digital signals for closed-loop control of STATCOM for reactive power compensation in PSCAD. This add-on can be an effective tool to give students better understanding of the space vector modulation algorithm for different control tasks in power electronics area, and can motivate them for learning.

  3. Adiabatic interpretation of a two-level atom diode, a laser device for unidirectional transmission of ground-state atoms

    International Nuclear Information System (INIS)

    Ruschhaupt, A.; Muga, J. G.

    2006-01-01

    We present a generalized two-level scheme for an 'atom diode', namely, a laser device that lets a two-level ground-state atom pass in one direction, say from left to right, but not in the opposite direction. The laser field is composed of two lateral state-selective mirror regions and a central pumping region. We demonstrate the robustness of the scheme and propose a physical realization. It is shown that the inclusion of a counterintuitive laser field blocking the excited atoms on the left side of the device is essential for a perfect diode effect. The reason for this, the diodic behavior, and the robustness may be understood with an adiabatic approximation. The conditions to break down the approximation, which imply also the diode failure, are analyzed

  4. Two-level MOC calculation scheme in APOLLO2 for cross-section library generation for LWR hexagonal assemblies

    International Nuclear Information System (INIS)

    Petrov, Nikolay; Todorova, Galina; Kolev, Nikola; Damian, Frederic

    2011-01-01

    The accurate and efficient MOC calculation scheme in APOLLO2, developed by CEA for generating multi-parameterized cross-section libraries for PWR assemblies, has been adapted to hexagonal assemblies. The neutronic part of this scheme is based on a two-level calculation methodology. At the first level, a multi-cell method is used in 281 energy groups for cross-section definition and self-shielding. At the second level, precise MOC calculations are performed in a collapsed energy mesh (30-40 groups). In this paper, the application and validation of the two-level scheme for hexagonal assemblies is described. Solutions for a VVER assembly are compared with TRIPOLI4® calculations and direct 281g MOC solutions. The results show that the accuracy is close to that of the 281g MOC calculation while the CPU time is substantially reduced. Compared to the multi-cell method, the accuracy is markedly improved. (author)

  5. Fabrication of Ni stamp with high aspect ratio, two-leveled, cylindrical microstructures using dry etching and electroplating

    DEFF Research Database (Denmark)

    Petersen, Ritika Singh; Keller, Stephan Sylvest; Hansen, Ole

    2015-01-01

    obtained by defining a reservoir and a separating trench with different depths of 85 and 125 μm, respectively, in a single embossing step. The fabrication of the required two leveled stamp is done using a modified DEEMO (dry etching, electroplating and molding) process. Dry etching using the Bosch process...... and electroplating are optimized to obtain a stamp with smooth stamp surfaces and a positive sidewall profile. Using this stamp, hot embossing is performed successfully with excellent yield and high replication fidelity....

  6. Coherent control of the group velocity in a dielectric slab doped with duplicated two-level atoms

    Science.gov (United States)

    Ziauddin; Chuang, You-Lin; Lee, Ray-Kuang; Qamar, Sajid

    2016-01-01

    Coherent control of reflected and transmitted pulses is investigated theoretically through a slab doped with atoms in a duplicated two-level configuration. When a strong control field and a relatively weak probe field are employed, coherent control of the group velocity is achieved via changing the phase shift ϕ between control and probe fields. Furthermore, the peak values in the delay time of the reflected and transmitted pulses are also studied by varying the phase shift ϕ.

  7. Performance and meat quality traits of beef heifers fed with two levels of concentrate and ruminally undegradable protein.

    Science.gov (United States)

    Duarte, Marcio de Souza; Paulino, Pedro Veiga Rodrigues; Valadares Filho, Sebastião de Campos; Paulino, Mario Fonseca; Detmann, Edenio; Zervoudakis, Joanis Tilemahos; Monnerat, João Paulo Ismerio dos Santos; Viana, Gabriel da Silva; Silva, Luiz Henrique P; Serão, Nicola Vergara Lopes

    2011-04-01

    The effects of two levels of concentrate and ruminally undegradable protein (RUP) on performance, intake, digestibility, carcass characteristics, meat quality traits, and commercial cuts yield were assessed. Twenty crossbred heifers (240 kg average body weight) were used. At the beginning of the trial, four animals were slaughtered as reference group and the 16 remaining animals were randomly assigned to four treatments, in a 2 × 2 factorial design: two levels of concentrate (40% and 80%, dry matter (DM) basis) and two levels of RUP (48.79% and 27.19% of CP). At the end of the trial, all the animals were slaughtered. There was no interaction (P > 0.05) between concentrate and RUP levels. Dry matter intake and nutrients digestibility was not affected (P > 0.05) by RUP level. Heifers fed the highest RUP level had greater (P  0.05) DMI and ADG. Heifers fed diets with 80% concentrate had greater intake of TDN and EE, and lower intake of NDF (P RUP levels did not affect (P > 0.05) the carcass characteristics and carcass gain composition. Heifers fed 80% concentrate diets had larger (P  0.05) the composition of carcass gain. There was no effect (P > 0.05) of RUP and concentrate levels on meat quality traits and commercial cut yields.

  8. An Indication of Reliability of the Two-Level Approach of the AWIN Welfare Assessment Protocol for Horses

    Directory of Open Access Journals (Sweden)

    Irena Czycholl

    2018-01-01

    Full Text Available To enhance feasibility, the Animal Welfare Indicators (AWIN assessment protocol for horses consists of two levels: the first is a visual inspection of a sample of horses performed from a distance, the second a close-up inspection of all horses. The aim was to analyse whether information would be lost if only the first level were performed. In this study, 112 first and 112 second level assessments carried out on a subsequent day by one observer were compared by calculating the Spearman’s Rank Correlation Coefficient (RS, Intraclass Correlation Coefficients (ICC, Smallest Detectable Changes (SDC and Limits of Agreements (LoA. Most indicators demonstrated sufficient reliability between the two levels. Exceptions were the Horse Grimace Scale, the Avoidance Distance Test and the Voluntary Human Approach Test (e.g., Voluntary Human Approach Test: RS: 0.38, ICC: 0.38, SDC: 0.21, LoA: −0.25–0.17, which could, however, be also interpreted as a lack of test-retest reliability. Further disagreement was found for the indicator consistency of manure (RS: 0.31, ICC: 0.38, SDC: 0.36, LoA: −0.38–0.36. For these indicators, an adaptation of the first level would be beneficial. Overall, in this study, the division into two levels was reliable and might therewith have the potential to enhance feasibility in other welfare assessment schemes.

  9. Manual for subject analysis

    International Nuclear Information System (INIS)

    2002-01-01

    This document is one in a series of publications known as the ETDE/INIS Joint Reference Series and also constitutes a part of the ETDE Procedures Manual. It presents the rules, guidelines and procedures to be adopted by centers submitting input to the International Nuclear Information System (INIS) or the Energy Technology Data Exchange (ETDE). It is a manual for the subject analysis part of input preparation, meaning the selection, subject classification, abstracting and subject indexing of relevant publications, and is to be used in conjunction with the Thesauruses, Subject Categories documents and the documents providing guidelines for the preparation of abstracts. The concept and structure of the new manual are intended to describe in a logical and efficient sequence all the steps comprising the subject analysis of documents to be reported to INIS or ETDE. The manual includes new chapters on preparatory analysis, subject classification, abstracting and subject indexing, as well as rules, guidelines, procedures, examples and a special chapter on guidelines and examples for subject analysis in particular subject fields. (g.t.; a.n.)

  10. Comparison of Cervical Kinematics, Pain, and Functional Disability Between Single- and Two-level Anterior Cervical Discectomy and Fusion.

    Science.gov (United States)

    Chien, Andy; Lai, Dar-Ming; Wang, Shwu-Fen; Hsu, Wei-Li; Cheng, Chih-Hsiu; Wang, Jaw-Lin

    2016-08-01

    A prospective, time series design. The purpose of this study is two-fold: firstly, to investigate the impact of altered cervical alignment and range of motion (ROM) on patients' self-reported outcomes after anterior cervical discectomy and fusion (ACDF), and secondly, to comparatively differentiate the influence of single- and two-level ACDF on the cervical ROM and adjacent segmental kinematics up to 12-month postoperatively. ACDF is one of the most commonly employed surgical interventions to treat degenerative disc disease. However, there are limited in vivo data on the impact of ACDF on the cervical kinematics and its association with patient-reported clinical outcomes. Sixty-two patients (36 males; 55.63 ± 11.6 yrs) undergoing either a single- or consecutive two-level ACDF were recruited. The clinical outcomes were assessed with the Pain Visual Analogue Scale (VAS) and the Neck Disability Index (NDI). Radiological results included cervical lordosis, global C2-C7 ROM, ROM of the Functional Spinal Unit (FSU), and its adjacent segments. The outcome measures were collected preoperatively and then at 3, 6, and 12-month postoperatively. A significant reduction of both VAS and NDI was found for both groups from the preoperative to 3-month period (P < 0.01). Pearson correlation revealed no significant correlation between global ROM with neither VAS (P = 0.667) nor NDI (P = 0.531). A significant reduction of global ROM was identified for the two-level ACDF group at 12 months (P = 0.017) but not for the single-level group. A significant interaction effect was identified for the upper adjacent segment ROM (P = 0.024) but not at the lower adjacent segment. Current study utilized dynamic radiographs to comparatively evaluate the biomechanical impact of single- and two-level ACDF. The results highlighted that the two-level group demonstrated a greater reduction of global ROM coupled with an increased upper adjacent segmental compensatory motions that

  11. Television system in which digitised picture signals subjected to a transform coding are transmitted from an encoding station to a decoding station

    NARCIS (Netherlands)

    1987-01-01

    In a television system a digital picture signal is subjected to a transform coding for the purpose of bit rate reduction. In order to detect motion effects between the two fields of a picture, these fields are also examined in a motion detector 8310. If no motion is detected, intraframe transform is

  12. The proceduralisation of data protection remedies under EU data protection law : Towards a more effective and data subject-oriented remedial system?

    NARCIS (Netherlands)

    Galetta, Antonella; de Hert, Paul

    2015-01-01

    The proceduralisation of data protection remedies under EU data protection law: towards a more effective and data subject-oriented remedial system?
The right to remedy breaches of data protection is laid down in both Directive 95/46/EC (Art. 22) and the Council of Europe Data Protection Convention

  13. WordPress as a Content Management System for a Library Web Site: How to Create a Dynamically Generated Subject Guide

    OpenAIRE

    Joshua Dodson

    2008-01-01

    This article explains a method of generating dynamic subject guides through the WordPress content management system. This method includes the use of the Exec-PHP WordPress plugin and additional PHP code to create a new category-based loop within the preexisting WordPress loop. Example code and screenshots are provided.

  14. Multicausal systems ask for multicausal approaches: A network perspective on subjective well-being in individuals with autism spectrum disorder.

    Science.gov (United States)

    Deserno, Marie K; Borsboom, Denny; Begeer, Sander; Geurts, Hilde M

    2017-11-01

    Given the heterogeneity of autism spectrum disorder, an important limitation of much autism spectrum disorder research is that outcome measures are statistically modeled as separate dependent variables. Often, their multivariate structure is either ignored or treated as a nuisance. This study aims to lift this limitation by applying network analysis to explicate the multivariate pattern of risk and success factors for subjective well-being in autism spectrum disorder. We estimated a network structure for 27 potential factors in 2341 individuals with autism spectrum disorder to assess the centrality of specific life domains and their importance for well-being. The data included both self- and proxy-reported information. We identified social satisfaction and societal contribution as the strongest direct paths to subjective well-being. The results suggest that an important contribution to well-being lies in resources that allow the individual to engage in social relations, which influence well-being directly. Factors most important in determining the network's structure include self-reported IQ, living situation, level of daily activity, and happiness. Number of family members with autism spectrum disorder and openness about one's diagnosis are least important of all factors for subjective well-being. These types of results can serve as a roadmap for interventions directed at improving the well-being of individuals with autism spectrum disorder.

  15. Informational provision as the factor of effective cooperation between the subject and object in the system of business management

    OpenAIRE

    Netreba, I.

    2009-01-01

    The article reveals: ITsignificance for providing of effective communications in business management system; approach analysis for specification of such categories as "economic information", "information support", "information management system"; classification of economic information; reasons for introduction of integrated automation systems into management.

  16. The Effects of Two Levels of Linguistic Constraint on Echolalia and Generative Language Production in Children with Autism.

    Science.gov (United States)

    Rydell, Patrick J.; Mirenda, Pat

    1991-01-01

    This study of 3 boys (ages 5-6) with autism found that adult high-constraint antecedent utterances elicited more verbal utterances in general, including subjects' echolalia; adult low-constraint utterances elicited more subject high-constraint utterances; and the degree of adult-utterance constraint did not influence the mean lengths of subjects'…

  17. RUSSIAN LAW SUBJECTS

    Directory of Open Access Journals (Sweden)

    D.N. Bakhrakh

    2006-03-01

    Full Text Available The question about the subjects of law branches is concerning the number of most important and difficult in law science. Its right decision influences on the subject of law regulation, precise definition of addressees of law norms, the volume of their rights and duties, the limits of action of norms of Main part of the branch, its principles. Scientific investigations, dedicated to law subjects system, promote the development of recommendations for the legislative and law applying activity; they are needed for scientific work organization and student training, for preparing qualified lawyers.

  18. 7. ordinance to amend the ordinance concerning fees for inspection of plants and systems subject to surveyance

    International Nuclear Information System (INIS)

    1983-01-01

    The fees to be levied for inspection largely remained the same since April 1, 1977 for the majority of industrial plants. The seventh amendment is intended to bring about an adjustment of fees to current costs of inspection. Considering the differing increase in fees for the various types of plants, an average increase of 7% is to be expected according to the draft ordinance. The additional expense to be borne by the operators of industrial plants subject to surveyance are low: an effect on consumer prices hence is not to be expected. (orig.) [de

  19. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    International Nuclear Information System (INIS)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon

    2010-01-01

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)

  20. Two-level anterior lumbar interbody fusion with percutaneous pedicle screw fixation. A minimum 3-year follow-up study

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Yeob; Lee, Sang-Ho; Maeng, Dae-Hyeon [Wooridul Spine Hospital, Seoul (Korea, Republic of)

    2010-08-15

    The clinical and radiological outcomes of two-level anterior lumbar interbody fusion (ALIF) with percutaneous pedicle screw fixation (PSF) were evaluated in 24 consecutive patients who underwent two level ALIF with percutaneous PSF for segmental instability and were followed up for more than 3 years. Clinical outcomes were assessed using a visual analogue scale (VAS) score and the Oswestry Disability Index (ODI). Sagittal alignment, bone union, and adjacent segment degeneration (ASD) were assessed using radiography and magnetic resonance imaging. The mean age of the patients at the time of operation was 56.3 years (range 39-70 years). Minor complications occurred in 2 patients in the perioperative period. At a mean follow-up duration of 39.4 months (range 36-42 months), VAS scores for back pain and leg pain, and ODI score decreased significantly (from 6.5, 6.8, and 46.9% to 3.0, 1.9, and 16.3%, respectively). Clinical success was achieved in 22 of the 24 patients. The mean segmental lordosis, whole lumbar lordosis, and sacral tilt significantly increased after surgery (from 25.1deg, 39.2deg, and 32.6deg to 32.9deg, 44.5deg, and 36.6deg, respectively). Solid fusion was achieved in 21 patients. ASD was found in 8 of the 24 patients. No patient underwent revision surgery due to nonunion or ASD. Two-level ALIF with percutaneous PSF yielded satisfactory clinical and radiological outcomes and could be a useful alternative to posterior fusion surgery. (author)