WorldWideScience

Sample records for quasiphasematched concurrent nonlinearities

  1. Complete modulational-instability gain spectrum of nonlinear quasi-phase-matching gratings

    DEFF Research Database (Denmark)

    Corney, Joel F.; Bang, Ole

    2004-01-01

    We consider plane waves propagating in quadratic nonlinear slab waveguides with nonlinear quasi-phasematching gratings. We predict analytically and verify numerically the complete gain spectrum for transverse modulational instability, including hitherto undescribed higher-order gain bands....

  2. Asymmetric induced cubic nonlinearities in homogeneous and quasi-phase-matched quadratic materials: signature and importance

    DEFF Research Database (Denmark)

    Bang, Ole; Corney, Joel Frederick

    2001-01-01

    In continuous-wave operation asymmetric induced nonlinearities induce an intensity-dependent phase mismatch that implies a nonzero so-called separatrix intensity, the crossing of which changes the one-period phase shift of the fundamental by Pi , with obvious use in switching applications.......We derived a formula for this QPM-induced separatrix intensity that corrects earlier estimates by a factor of 5.3, and we found the optimum crystal lengths for a flat phase-versus-intensity response on each side of the separatrix...

  3. Intracavity quasi-phase-matched self-frequency conversion in a periodically poled Nd:Mg:LiNbO3 crystal

    International Nuclear Information System (INIS)

    Laptev, G D; Novikov, Aleksei A

    2001-01-01

    The theory of intracavity quasi-phase-matched self-frequency conversion in an active nonlinear periodically poled structure is developed. The processes of quasi-phase-matched self-frequency doubling, self-halving and mixing using the pump wave in a periodically poled Nd:Mg:LiNbO 3 crystal are studied. The dependences of the efficiency of nonlinear optical conversion in these processes on the reflection coefficient of the output mirror and on linear losses in the medium are investigated. (nonlinear optical phenomena)

  4. Nonlinear analysis for dual-frequency concurrent energy harvesting

    Science.gov (United States)

    Yan, Zhimiao; Lei, Hong; Tan, Ting; Sun, Weipeng; Huang, Wenhu

    2018-05-01

    The dual-frequency responses of the hybrid energy harvester undergoing the base excitation and galloping were analyzed numerically. In this work, an approximate dual-frequency analytical method is proposed for the nonlinear analysis of such a system. To obtain the approximate analytical solutions of the full coupled distributed-parameter model, the forcing interactions is first neglected. Then, the electromechanical decoupled governing equation is developed using the equivalent structure method. The hybrid mechanical response is finally separated to be the self-excited and forced responses for deriving the analytical solutions, which are confirmed by the numerical simulations of the full coupled model. The forced response has great impacts on the self-excited response. The boundary of Hopf bifurcation is analytically determined by the onset wind speed to galloping, which is linearly increased by the electrical damping. Quenching phenomenon appears when the increasing base excitation suppresses the galloping. The theoretical quenching boundary depends on the forced mode velocity. The quenching region increases with the base acceleration and electrical damping, but decreases with the wind speed. Superior to the base-excitation-alone case, the existence of the aerodynamic force protects the hybrid energy harvester at resonance from damages caused by the excessive large displacement. From the view of the harvested power, the hybrid system surpasses the base-excitation-alone system or the galloping-alone system. This study advances our knowledge on intrinsic nonlinear dynamics of the dual-frequency energy harvesting system by taking advantage of the analytical solutions.

  5. Angular quasi-phase-matching experiments and determination of accurate Sellmeier equations for 5%MgO:PPLN.

    Science.gov (United States)

    Brand, Pierre; Boulanger, Benoît; Segonds, Patricia; Petit, Yannick; Félix, Corinne; Ménaert, Bertrand; Taira, Takunori; Ishizuki, Hideki

    2009-09-01

    We validated the theory of angular quasi-phase-matching (AQPM) by performing measurements of second-harmonic generation and difference-frequency generation. A nonlinear least-squares fitting of these experimental data led to refine the Sellmeier equations of 5%MgO:PPLN that are now valid over the complete transparency range of the crystal. We also showed that AQPM exhibits complementary spectral ranges and acceptances compared with birefringence phase matching.

  6. Accurate switching intensities and length scales in quasi-phase-matched materials

    DEFF Research Database (Denmark)

    Bang, Ole; Graversen, Torben Winther; Corney, Joel Frederick

    2001-01-01

    We consider unseeded typeI second-harmonic generation in quasi-phase-matched quadratic nonlinear materials and derive an accurate analytical expression for the evolution of the average intensity. The intensity- dependent nonlinear phase mismatch that is due to the cubic nonlinearity induced...... by quasi phase matching is found. The equivalent formula for the intensity of maximum conversion, the crossing of which changes the one-period nonlinear phase shift of the fundamental abruptly by p , corrects earlier estimates [Opt.Lett. 23, 506 (1998)] by a factor of 5.3. We find the crystal lengths...... that are necessary to obtain an optimal flat phase versus intensity response on either side of this separatrix intensity....

  7. Modulational-instability gain bands in quasi-phase-matched materials

    International Nuclear Information System (INIS)

    Corney, J.F.; Bang, O.

    2002-01-01

    Full text: Quadratically nonlinear materials are of significant technological interest in optics because of their strong and fast cascaded nonlinearities, which are accessed most efficiently with quasi-phase-matching (QPM) techniques. We study the gain spectra of modulational instabilities (Ml) in quadratic materials where the linear and nonlinear properties are modulated with QPM gratings. The periods and intensity-dependence of the Ml can now be measured in the laboratory. Using an exact Floquet theory, we find that novel low- and high-frequency bands appear in the gain spectrum (gain versus transverse spatial frequency). The high-frequency gain bands are a general feature of gain spectra for QPM gratings. They form part of an extensive series of bands that correspond to Ml in the non-phase-matched, quickly varying components of the fields. The low-frequency bands correspond to Ml in the phase-matched DC components of the fields and are accurately predicted by a simple average theory. This theory includes the effect of the quickly varying components as induced cubic terms, which can be strong enough to suppress the low-frequency bands, in which case dark solitons and other broad beams may be effectively stable, since the high-frequency bands are typically small

  8. Diffraction study of duty-cycle error in ferroelectric quasi-phase-matching gratings with Gaussian beam illumination

    Science.gov (United States)

    Dwivedi, Prashant Povel; Kumar, Challa Sesha Sai Pavan; Choi, Hee Joo; Cha, Myoungsik

    2016-02-01

    Random duty-cycle error (RDE) is inherent in the fabrication of ferroelectric quasi-phase-matching (QPM) gratings. Although a small RDE may not affect the nonlinearity of QPM devices, it enhances non-phase-matched parasitic harmonic generations, limiting the device performance in some applications. Recently, we demonstrated a simple method for measuring the RDE in QPM gratings by analyzing the far-field diffraction pattern obtained by uniform illumination (Dwivedi et al. in Opt Express 21:30221-30226, 2013). In the present study, we used a Gaussian beam illumination for the diffraction experiment to measure noise spectra that are less affected by the pedestals of the strong diffraction orders. Our results were compared with our calculations based on a random grating model, demonstrating improved resolution in the RDE estimation.

  9. Equilibrium switching and mathematical properties of nonlinear interaction networks with concurrent antagonism and self-stimulation

    International Nuclear Information System (INIS)

    Rabajante, Jomar Fajardo; Talaue, Cherryl Ortega

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •Properties of n-dimensional decision model of competitive interaction networks. •Graphical technique for component-wise and steady state stability analysis. •Search for parameter conditions that control equilibrium switching. •Illustrations of multi-stable systems and repressilators. -- Abstract: Concurrent decision-making model (CDM) of interaction networks with more than two antagonistic components represents various biological systems, such as gene interaction, species competition and mental cognition. The CDM model assumes sigmoid kinetics where every component stimulates itself but concurrently represses the others. Here we prove generic mathematical properties (e.g., location and stability of steady states) of n-dimensional CDM with either symmetric or asymmetric reciprocal antagonism between components. Significant modifications in parameter values serve as biological regulators for inducing steady state switching by driving a temporal state to escape an undesirable equilibrium. Increasing the maximal growth rate and decreasing the decay rate can expand the basin of attraction of a steady state that contains the desired dominant component. Perpetually adding an external stimulus could shut down multi-stability of the system which increases the robustness of the system against stochastic noise. We further show that asymmetric interaction forming a repressilator-type network generates oscillatory behavior

  10. Spatial Solitons and Induced Kerr Effects in Quasi-Phase-Matched Quadratic Media

    DEFF Research Database (Denmark)

    Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yu.S.

    1997-01-01

    We show that the evolution of the average intensity of cw beams in a quasi-phase-matched quadratic (or chi((2))) medium is strongly influenced by induced Kerr effects, such as self- and cross-phase modulation. We prove the existence of rapidly oscillating solitary waves (a spatial analog of the g......We show that the evolution of the average intensity of cw beams in a quasi-phase-matched quadratic (or chi((2))) medium is strongly influenced by induced Kerr effects, such as self- and cross-phase modulation. We prove the existence of rapidly oscillating solitary waves (a spatial analog...

  11. Retrieving quasi-phase-matching structure with discrete layer-peeling method

    DEFF Research Database (Denmark)

    Zhang, Q. W.; Zeng, Xianglong; Wang, M.

    2012-01-01

    An approach to reconstruct a quasi-phase-matching grating by using a discrete layer-peeling algorithm is presented. Experimentally measured output spectra of Solc-type filters, based on uniform and chirped QPM structures, are used in the discrete layer-peeling algorithm. The reconstructed QPM...

  12. Induced Kerr effects and self-guided beams in quasi-phase-matched quadratic media [CBC4

    DEFF Research Database (Denmark)

    Clausen, Carl A. Balslev; Bang, Ole; Kivshar, Yuri S.

    1997-01-01

    We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons......We show that quasi-phase-matching of quadratic media induces Kerr effects, such as self- and cross-phase modulation, and leads to the existence of a novel class of solitary waves, QPM-solitons...

  13. Engineered nonlinear lattices

    DEFF Research Database (Denmark)

    Clausen, Carl A. Balslev; Christiansen, Peter Leth; Torner, L.

    1999-01-01

    We show that with the quasi-phase-matching technique it is possible to fabricate stripes of nonlinearity that trap and guide light like waveguides. We investigate an array of such stripes and find that when the stripes are sufficiently narrow, the beam dynamics is governed by a quadratic nonlinear...... discrete equation. The proposed structure therefore provides an experimental setting for exploring discrete effects in a controlled manner. In particular, we show propagation of breathers that are eventually trapped by discreteness. When the stripes are wide the beams evolve in a structure we term...

  14. Quadratic soliton self-reflection at a quadratically nonlinear interface

    Science.gov (United States)

    Jankovic, Ladislav; Kim, Hongki; Stegeman, George; Carrasco, Silvia; Torner, Lluis; Katz, Mordechai

    2003-11-01

    The reflection of bulk quadratic solutions incident onto a quadratically nonlinear interface in periodically poled potassium titanyl phosphate was observed. The interface consisted of the boundary between two quasi-phase-matched regions displaced from each other by a half-period. At high intensities and small angles of incidence the soliton is reflected.

  15. Application of mid-infrared pulses for quasi-phase-matching of high-order harmonics in silver plasma.

    Science.gov (United States)

    Ganeev, Rashid A; Husakou, Anton; Suzuki, Masayuki; Kuroda, Hiroto

    2016-02-22

    We demonstrate the quasi-phase-matching of a group of harmonics generated in Ag multi-jet plasma using tunable pulses in the region of 1160 - 1540 nm and their second harmonic emission. The numerical treatment of this effect includes microscopic description of the harmonic generation, propagation of the pump pulse, and the propagation of the generated harmonics. We obtained more than 30-fold growth of harmonics at the conditions of quasi-phase-matching in the region of 35 nm using eight-jet plasma compared with the case of imperforated plasma.

  16. Characterization of quasi-phase-matching gratings in quadratic media through double-pass second-harmonic power measurements

    DEFF Research Database (Denmark)

    Johansen, Steffen Kjær; Baldi, Pascal

    2004-01-01

    A new scheme for nondestructive characterization of quasi-phase-matching grating structures and temperature gradients through inverse Fourier theory using second-harmonic-generation experiments is proposed. By inserting a mirror to reflect the signals back through the sample, we show how...

  17. Concurrent Collections

    OpenAIRE

    Budimlić, Zoran; Burke, Michael; Cavé, Vincent; Knobe, Kathleen; Lowney, Geoff; Newton, Ryan; Palsberg, Jens; Peixotto, David; Sarkar, Vivek; Schlimbach, Frank; Taşırlar, Sağnak

    2010-01-01

    We introduce the Concurrent Collections (CnC) programming model. CnC supports flexible combinations of task and data parallelism while retaining determinism. CnC is implicitly parallel, with the user providing high-level operations along with semantic ordering constraints that together form a CnC graph. We formally describe the execution semantics of CnC and prove that the model guarantees deterministic computation. We evaluate the performance of CnC implementations on several applications an...

  18. Squeezed-light generation in a nonlinear planar waveguide with a periodic corrugation

    International Nuclear Information System (INIS)

    Perina, Jan Jr.; Haderka, Ondrej; Sibilia, Concita; Bertolotti, Mario; Scalora, Michael

    2007-01-01

    Two-mode nonlinear interaction (second-harmonic and second-subharmonic generation) in a planar waveguide with a small periodic corrugation at the surface is studied. Scattering of the interacting fields on the corrugation leads to constructive interference that enhances the nonlinear process provided that all the interactions are phase matched. Conditions for the overall phase matching are found. Compared with a perfectly quasi-phase-matched waveguide, better values of squeezing as well as higher intensities are reached under these conditions. Procedure for finding optimum values of parameters for squeezed-light generation is described

  19. Generation of green frequency comb from chirped χ{sup (2)} nonlinear photonic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Lai, C.-M. [Department of Electronic Engineering, Ming Chuan University, Taoyuan, Taiwan (China); Chang, K.-H.; Yang, Z.-Y.; Fu, S.-H.; Tsai, S.-T.; Hsu, C.-W.; Peng, L.-H. [Department of Electrical Engineering and Graduate Institute of Photonics and Optoelectronics, National Taiwan University, Taipei, Taiwan (China); Yu, N. E. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Boudrioua, A. [LPL, CNRS - UMR 7538, Université Paris 13, Sorbone Paris Cité (France); Kung, A. H. [Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan (China); Institute of Photonics Technologies, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-12-01

    Spectrally broad frequency comb generation over 510–555 nm range was reported on chirped quasi-phase-matching (QPM) χ{sup (2)} nonlinear photonic crystals of 12 mm length with periodicity stepwise increased from 5.9 μm to 7.1 μm. When pumped with nanosecond infrared (IR) frequency comb derived from a QPM optical parametric oscillator (OPO) and spanned over 1040 nm to 1090 nm wavelength range, the 520 nm to 545 nm up-converted green spectra were shown to consist of contributions from (a) second-harmonic generation among the signal or the idler modes, and (b) sum-frequency generation (SFG) from the neighboring pairs of the signal or the idler modes. These mechanisms led the up-converted green frequency comb to have the same mode spacing of 450 GHz as that in the IR-OPO pump comb. As the pump was further detuned from the aforementioned near-degeneracy point and moved toward the signal (1020–1040 nm) and the idler (1090–1110 nm) spectral range, the above QPM parametric processes were preserved in the chirped QPM devices to support up-converted green generation in the 510–520 nm and the 545–555 nm spectral regime. Additional 530–535 nm green spectral generation was also observed due to concurrence of multi-wavelength SFG processes between the (signal, idler) mode pairs. These mechanisms facilitate the chirped QPM device to support a single-pass up-conversion efficiency ∼10% when subject to an IR-OPO pump comb with 200 mW average power operated near- or off- the degeneracy point.

  20. Theoretical study and experimental scheme for the generation of a 1064-nm continuous variable entangled light source with quasi-phase-matching PPKTP crystal

    International Nuclear Information System (INIS)

    Liu, W.Y.; Bi, S.W.

    2011-01-01

    Beginning from Maxwell's equations, various factors required for the non-degenerate optical parametric amplifier (NOPA) to operate are considered step by step. Analytic expressions are obtained, generated from the experimental parameters and through the numerical simulation of the quantum-correlated spectrum between the signal and the idler modes from the NOPA operating below threshold. On this basis, an experimental program is designed for the generation of a 1064-nm continuous variable entanglement light source with a quasi-phase-matching periodical polarized KTiOPO 4 (PPKTP) crystal through a below-threshold optical parametric down-conversion process. This will play a crucial role in subsequent experiments.

  1. Terahertz-wave surface-emitted difference-frequency generation without quasi-phase-matching technique.

    Science.gov (United States)

    Avetisyan, Yuri H

    2010-08-01

    A scheme of terahertz (THz)-wave surface-emitted difference-frequency generation (SEDFG), which lacks the drawbacks associated with the usage of periodically orientation-inverted structures, is proposed. It is shown that both material birefringence of the bulk LiNbO(3) crystal and modal birefringence of GaAs/AlAs waveguide are sufficient to obtain SEDFG up to a frequency of approximately 3THz. The simplicity of the proposed scheme, along with the fact that there is a much smaller THz-wave decay in nonlinear crystal, makes it a good candidate for the practical realization of efficient THz generation. The use of a GaAs waveguide with an oxidized AlAs layer is proposed for enhanced THz-wave SEDFG in the vicinity of the GaAs polariton resonance at 8THz.

  2. Concurrent weighted logic

    DEFF Research Database (Denmark)

    Xue, Bingtian; Larsen, Kim Guldstrand; Mardare, Radu Iulian

    2015-01-01

    We introduce Concurrent Weighted Logic (CWL), a multimodal logic for concurrent labeled weighted transition systems (LWSs). The synchronization of LWSs is described using dedicated functions that, in various concurrency paradigms, allow us to encode the compositionality of LWSs. To reflect these......-completeness results for this logic. To complete these proofs we involve advanced topological techniques from Model Theory....

  3. Measuring and modelling concurrency

    Science.gov (United States)

    Sawers, Larry

    2013-01-01

    This article explores three critical topics discussed in the recent debate over concurrency (overlapping sexual partnerships): measurement of the prevalence of concurrency, mathematical modelling of concurrency and HIV epidemic dynamics, and measuring the correlation between HIV and concurrency. The focus of the article is the concurrency hypothesis – the proposition that presumed high prevalence of concurrency explains sub-Saharan Africa's exceptionally high HIV prevalence. Recent surveys using improved questionnaire design show reported concurrency ranging from 0.8% to 7.6% in the region. Even after adjusting for plausible levels of reporting errors, appropriately parameterized sexual network models of HIV epidemics do not generate sustainable epidemic trajectories (avoid epidemic extinction) at levels of concurrency found in recent surveys in sub-Saharan Africa. Efforts to support the concurrency hypothesis with a statistical correlation between HIV incidence and concurrency prevalence are not yet successful. Two decades of efforts to find evidence in support of the concurrency hypothesis have failed to build a convincing case. PMID:23406964

  4. Multiple nonlinear Bragg diffraction of femtosecond laser pulses in a {\\chi^{(2)}} photonic lattice with hexagonal domains

    Science.gov (United States)

    Vyunishev, A. M.; Arkhipkin, V. G.; Baturin, I. S.; Akhmatkhanov, A. R.; Shur, V. Ya; Chirkin, A. S.

    2018-04-01

    The frequency doubling of femtosecond laser pulses in a two-dimensional (2D) rectangular nonlinear photonic lattice with hexagonal domains is studied experimentally and theoretically. The broad fundamental spectrum enables frequency conversion under nonlinear Bragg diffraction for a series of transverse orders at a fixed longitudinal quasi-phase-matching order. The consistent nonstationary theory of the frequency doubling of femtosecond laser pulses is developed using the representation based on the reciprocal lattice of the structure. The calculated spatial distribution of the second-harmonic spectral intensity agrees well with the experimental data. The condition for multiple nonlinear Bragg diffraction in a 2D nonlinear photonic lattice is offered. The hexagonal shape of the domains contributes to multibeam second harmonic excitation. The maximum conversion efficiency for a series of transverse orders in the range 0.01%-0.03% is obtained.

  5. Generalization of concurrence vectors

    International Nuclear Information System (INIS)

    Yu Changshui; Song Heshan

    2004-01-01

    In this Letter, based on the generalization of concurrence vectors for bipartite pure state with respect to employing tensor product of generators of the corresponding rotation groups, we generalize concurrence vectors to the case of mixed states; a new criterion of separability of multipartite pure states is given out, for which we define a concurrence vector; we generalize the vector to the case of multipartite mixed state and give out a good measure of free entanglement

  6. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia Posso, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...... reflect the reactive interactions between concurrent constraint processes and their environment, as well as internal interactions between individual processes. Relationships between the suggested notions are studied, and they are all proved to be decidable for a substantial fragment of the calculus...

  7. Building Safe Concurrency Abstractions

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    2014-01-01

    Concurrent object-oriented programming in Beta is based on semaphores and coroutines and the ability to define high-level concurrency abstractions like monitors, and rendezvous-based communication, and their associated schedulers. The coroutine mechanism of SIMULA has been generalized into the no......Concurrent object-oriented programming in Beta is based on semaphores and coroutines and the ability to define high-level concurrency abstractions like monitors, and rendezvous-based communication, and their associated schedulers. The coroutine mechanism of SIMULA has been generalized...

  8. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank Dan

    2002-01-01

    The ntcc calculus is a model of non-deterministic temporal concurrent constraint programming. In this paper we study behavioral notions for this calculus. In the underlying computational model, concurrent constraint processes are executed in discrete time intervals. The behavioral notions studied...

  9. Impredicative concurrent abstract predicates

    DEFF Research Database (Denmark)

    Svendsen, Kasper; Birkedal, Lars

    2014-01-01

    We present impredicative concurrent abstract predicates { iCAP { a program logic for modular reasoning about concurrent, higher- order, reentrant, imperative code. Building on earlier work, iCAP uses protocols to reason about shared mutable state. A key novel feature of iCAP is the ability to dene...

  10. Automata and concurrency

    Energy Technology Data Exchange (ETDEWEB)

    Priese, L

    1983-07-01

    The author presents a precise notion of a realization (or simulation) of one concurrent system by another, and studies the relations of modular concurrent systems and non-persistent (i.e. With conflicts) concurrent systems in an automata theoretical style. He introduces a conception of realization that obeys three requirements: it allows for proper hierarchies in certain classes of concurrent systems; it allows for normal-form theorems, and the standard constructions of the literature remain realizations in formal concept; and it clarifies some counterintuitive examples. Further, although this realization conception is developed to translate the computational aspects of concurrent systems, it also gives a formal tool for the handling of synchronization problems. 38 references.

  11. Channel's Concurrence and Quantum Teleportation

    Institute of Scientific and Technical Information of China (English)

    LING Yin-Sheng

    2005-01-01

    Concurrence can measure the entanglement property of a system. If the channel is a pure state, positive concurrence state can afford the good performance in the teleportation process. If the channel ia a mixed state, positive concurrence state cannot assure the good performance in the teleportation. The conditions of the positive concurrence and the quantum teleportation in the Heisenberg spin ring is derived.

  12. Algebraic topology and concurrency

    DEFF Research Database (Denmark)

    Fajstrup, Lisbeth; Raussen, Martin; Goubault, Eric

    2006-01-01

    We show in this article that some concepts from homotopy theory, in algebraic topology,are relevant for studying concurrent programs. We exhibit a natural semantics of semaphore programs, based on partially ordered topological spaces, which are studied up to “elastic deformation” or homotopy...... differences between ordinary and directed homotopy through examples. We also relate the topological view to a combinatorial view of concurrent programs closer to transition systems, through the notion of a cubical set. Finally we apply some of these concepts to the proof of the safeness of a two...

  13. A Concurrent Logical Relation

    DEFF Research Database (Denmark)

    Birkedal, Lars; Sieczkowski, Filip; Thamsborg, Jacob Junker

    2012-01-01

    We present a logical relation for showing the correctness of program transformations based on a new type-and-effect system for a concurrent extension of an ML-like language with higher-order functions, higher-order store and dynamic memory allocation. We show how to use our model to verify a number....... To the best of our knowledge, this is the first such result for a concurrent higher-order language with higher-order store and dynamic memory allocation....

  14. Coalgebra, concurrency and control

    NARCIS (Netherlands)

    J.J.M.M. Rutten (Jan)

    1999-01-01

    textabstractCoalgebra is used to generalize notions and techniques from concurrency theory, in order to apply them to problems concerning the supervisory control of discrete event systems. The main ingredients of this approach are the characterization of controllability in terms of (a variant of)

  15. Correctness of concurrent processes

    NARCIS (Netherlands)

    E.R. Olderog (Ernst-Rüdiger)

    1989-01-01

    textabstractA new notion of correctness for concurrent processes is introduced and investigated. It is a relationship P sat S between process terms P built up from operators of CCS [Mi 80], CSP [Ho 85] and COSY [LTS 79] and logical formulas S specifying sets of finite communication sequences as in

  16. Concurrent credit portfolio losses.

    Science.gov (United States)

    Sicking, Joachim; Guhr, Thomas; Schäfer, Rudi

    2018-01-01

    We consider the problem of concurrent portfolio losses in two non-overlapping credit portfolios. In order to explore the full statistical dependence structure of such portfolio losses, we estimate their empirical pairwise copulas. Instead of a Gaussian dependence, we typically find a strong asymmetry in the copulas. Concurrent large portfolio losses are much more likely than small ones. Studying the dependences of these losses as a function of portfolio size, we moreover reveal that not only large portfolios of thousands of contracts, but also medium-sized and small ones with only a few dozens of contracts exhibit notable portfolio loss correlations. Anticipated idiosyncratic effects turn out to be negligible. These are troublesome insights not only for investors in structured fixed-income products, but particularly for the stability of the financial sector. JEL codes: C32, F34, G21, G32, H81.

  17. Temporal Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Valencia, Frank Dan

    Concurrent constraint programming (ccp) is a formalism for concurrency in which agents interact with one another by telling (adding) and asking (reading) information in a shared medium. Temporal ccp extends ccp by allowing agents to be constrained by time conditions. This dissertation studies...... temporal ccp by developing a process calculus called ntcc. The ntcc calculus generalizes the tcc model, the latter being a temporal ccp model for deterministic and synchronouss timed reactive systems. The calculus is built upon few basic ideas but it captures several aspects of timed systems. As tcc, ntcc...... structures, robotic devises, multi-agent systems and music applications. The calculus is provided with a denotational semantics that captures the reactive computations of processes in the presence of arbitrary environments. The denotation is proven to be fully-abstract for a substantial fragment...

  18. Concurrent radiotherapy and chemotherapy

    International Nuclear Information System (INIS)

    Fu, K.K.

    1985-01-01

    The principal objective of combining chemotherapy with radiotherapy (XRT) for the treatment of advanced head and neck cancer is to improve the therapeutic ratio through the enhancement of local control and reduction of distant metastases without excessively enhancing normal tissue effects. Improved tumour control can result from sole additivity of either therapy or direct interactions between drug and radiation leading to increased tumour cell kill. Chemotherapy may sensitize the cells to radiation, interfere with repair of sublethal or potentially lethal radiation damage, induce cell synchrony, and reduce tumour mass leading to reoxygenation and decreased fraction of resistant hypoxic cells. Radiation may improve drug accessibility to tumour cells and reduce tumour volume leading to increased cell proliferation and chemosensitivity. If the enhanced effects of combined therapy are purely additive, then the two modalities can be administered either sequentially or concurrently with the same results. However, if the enhanced effects result from the direct interaction between drug and radiation, it is necessary that the two modalities be administered concurrently and in close temporal proximity. This review summarizes the results of clinical studies in which chemotherapy was administered concurrently during the course of radiotherapy for patients with previously untreated advanced squamous cell carcinoma in the head and neck

  19. Concurrence Measurement for the Two-Qubit Optical and Atomic States

    Directory of Open Access Journals (Sweden)

    Lan Zhou

    2015-06-01

    Full Text Available Concurrence provides us an effective approach to quantify entanglement, which is quite important in quantum information processing applications. In the paper, we mainly review some direct concurrence measurement protocols of the two-qubit optical or atomic system. We first introduce the concept of concurrence for a two-qubit system. Second, we explain the approaches of the concurrence measurement in both a linear and a nonlinear optical system. Third, we introduce some protocols for measuring the concurrence of the atomic entanglement system.

  20. Concurrency in product realization

    Science.gov (United States)

    Kelly, Michael J.

    1994-03-01

    Technology per se does not provide a competitive advantage. Timely exploitation of technology is what gives the competitive edge, and this demands a major shift in the product development process and management of the industrial enterprise. `Teaming to win' is more than a management theme; it is the disciplined engineering practice that is essential to success in today's global marketplace. Teaming supports the concurrent engineering practices required to integrate the activities of people responsible for product realization through achievement of shorter development cycles, lower costs, and defect-free products.

  1. Domain Theory for Concurrency

    DEFF Research Database (Denmark)

    Nygaard, Mikkel

    and associated comonads, it highlights the role of linearity in concurrent computation. Two choices of comonad yield two expressive metalanguages for higher-order processes, both arising from canonical constructions in the model. Their denotational semantics are fully abstract with respect to contextual...... equivalence. One language, called HOPLA for Higher-Order Process LAnguage, derives from an exponential of linear logic. It can be viewed as an extension of the simply-typed lambda calculus with CCS-like nondeterministic sum and prefix operations, in which types express the form of computation path of which...

  2. Mastering concurrency in Go

    CERN Document Server

    Kozyra, Nathan

    2014-01-01

    A practical approach covering everything you need to know to get up and running with Go, starting with the basics and imparting increasingly more detail as the examples and topics become more complicated. The book utilizes a casual, conversational style, rife with actual code and historical anecdotes for perspective, as well as usable and extensible example applications. This book is intended for systems developers and programmers with some experience in either Go and/or concurrent programming who wish to become fluent in building high-performance applications that scale by leveraging single-c

  3. Morse Theory and Concurrency

    DEFF Research Database (Denmark)

    Wisniewski, Rafal

    2003-01-01

    The work is intended to provide some insight about concurrency theory using ideas from geometry and algebraic topology. We define a topological space containing all traces of execution of the computer program and the information about how time flows. This is the main difference with standard...... topological reasoning in which there is no information about relation "in time" among points. The main task is to define equivalence of paths reflecting execution of a program. We use the notion of homotopy history equivalence relation. The model space considered in this work is a differentiable manifold...

  4. Explicit time integration of finite element models on a vectorized, concurrent computer with shared memory

    Science.gov (United States)

    Gilbertsen, Noreen D.; Belytschko, Ted

    1990-01-01

    The implementation of a nonlinear explicit program on a vectorized, concurrent computer with shared memory is described and studied. The conflict between vectorization and concurrency is described and some guidelines are given for optimal block sizes. Several example problems are summarized to illustrate the types of speed-ups which can be achieved by reprogramming as compared to compiler optimization.

  5. Rethinking serializable multiversion concurrency control

    OpenAIRE

    Faleiro, Jose M.; Abadi, Daniel J.

    2014-01-01

    Multi-versioned database systems have the potential to significantly increase the amount of concurrency in transaction processing because they can avoid read-write conflicts. Unfortunately, the increase in concurrency usually comes at the cost of transaction serializability. If a database user requests full serializability, modern multi-versioned systems significantly constrain read-write concurrency among conflicting transactions and employ expensive synchronization patterns in their design....

  6. Quantify entanglement by concurrence hierarchy

    OpenAIRE

    Fan, Heng; Matsumoto, Keiji; Imai, Hiroshi

    2002-01-01

    We define the concurrence hierarchy as d-1 independent invariants under local unitary transformations in d-level quantum system. The first one is the original concurrence defined by Wootters et al in 2-level quantum system and generalized to d-level pure quantum states case. We propose to use this concurrence hierarchy as measurement of entanglement. This measurement does not increase under local quantum operations and classical communication.

  7. Concurrent Models for Object Execution

    OpenAIRE

    Diertens, Bob

    2012-01-01

    In previous work we developed a framework of computational models for the concurrent execution of functions on different levels of abstraction. It shows that the traditional sequential execution of function is just a possible implementation of an abstract computational model that allows for the concurrent execution of functions. We use this framework as base for the development of abstract computational models that allow for the concurrent execution of objects.

  8. Economic explanations for concurrent sourcing

    DEFF Research Database (Denmark)

    Mols, Niels Peter

    2010-01-01

    Concurrent sourcing is a phenomenon where firms simultaneously make and buy the same good, i.e. they simultaneously use the governance modes of market and hierarchy. Though concurrent sourcing seems to be widespread, few studies of sourcing have focused on this phenomenon. This paper reviews...... different economic explanations for why firms use concurrent sourcing. The distinctive features of the explanations are compared, and it is discussed how they may serve as a springboard for research on concurrent sourcing. Managerial implications are also offered....

  9. Concurrency Control for Transactional Drago

    OpenAIRE

    Patiño-Martinez, Marta; Jiménez-Peris, Ricardo; Kienzle, Jörg; Arévalo, Sergio

    2002-01-01

    The granularity of concurrency control has a big impact on the performance of transactional systems. Concurrency control granu- larity and data granularity (data size) are usually the same. The e ect of this coupling is that if a coarse granularity is used, the overhead of data access (number of disk accesses) is reduced, but also the degree of concurrency. On the other hand, if a ne granularity is chosen to achieve a higher degree of concurrency (there are less con icts), the cost of data ac...

  10. Measuring coherence with entanglement concurrence

    Science.gov (United States)

    Qi, Xianfei; Gao, Ting; Yan, Fengli

    2017-07-01

    Quantum coherence is a fundamental manifestation of the quantum superposition principle. Recently, Baumgratz et al (2014 Phys. Rev. Lett. 113 140401) presented a rigorous framework to quantify coherence from the view of theory of physical resource. Here we propose a new valid quantum coherence measure which is a convex roof measure, for a quantum system of arbitrary dimension, essentially using the generalized Gell-Mann matrices. Rigorous proof shows that the proposed coherence measure, coherence concurrence, fulfills all the requirements dictated by the resource theory of quantum coherence measures. Moreover, strong links between the resource frameworks of coherence concurrence and entanglement concurrence is derived, which shows that any degree of coherence with respect to some reference basis can be converted to entanglement via incoherent operations. Our work provides a clear quantitative and operational connection between coherence and entanglement based on two kinds of concurrence. This new coherence measure, coherence concurrence, may also be beneficial to the study of quantum coherence.

  11. Engineered Quasi-Phase Matching for Nonlinear Quantum Optics in Waveguides

    Science.gov (United States)

    Van Camp, Mackenzie A.

    Entanglement is the hallmark of quantum mechanics. Quantum entanglement--putting two or more identical particles into a non-factorable state--has been leveraged for applications ranging from quantum computation and encryption to high-precision metrology. Entanglement is a practical engineering resource and a tool for sidestepping certain limitations of classical measurement and communication. Engineered nonlinear optical waveguides are an enabling technology for generating entangled photon pairs and manipulating the state of single photons. This dissertation reports on: i) frequency conversion of single photons from the mid-infrared to 843nm as a tool for incorporating quantum memories in quantum networks, ii) the design, fabrication, and test of a prototype broadband source of polarization and frequency entangled photons; and iii) a roadmap for further investigations of this source, including applications in quantum interferometry and high-precision optical metrology. The devices presented herein are quasi-phase-matched lithium niobate waveguides. Lithium niobate is a second-order nonlinear optical material and can mediate optical energy conversion to different wavelengths. This nonlinear effect is the basis of both quantum frequency conversion and entangled photon generation, and is enhanced by i) confining light in waveguides to increase conversion efficiency, and ii) quasi-phase matching, a technique for engineering the second-order nonlinear response by locally altering the direction of a material's polarization vector. Waveguides are formed by diffusing titanium into a lithium niobate wafer. Quasi-phase matching is achieved by electric field poling, with multiple stages of process development and optimization to fabricate the delicate structures necessary for broadband entangled photon generation. The results presented herein update and optimize past fabrication techniques, demonstrate novel optical devices, and propose future avenues for device development

  12. Concurrent LISP and its interpreter

    Energy Technology Data Exchange (ETDEWEB)

    Tabata, K; Sugimoto, S; Ohno, Y

    1981-01-01

    In the research field of artificial intelligence many languages have been developed based on LISP, such as Planner, Conniver and so on. They have been developed to give users many useful facilities, especially for describing flexible control structures. Backtracking and coroutine facilities are typical ones introduced into these languages. Compared with backtracking and coroutine facilities, multi-process description facilities are considered to be a better alternative for writing well-structured programs. This paper describes concurrent LISP, a new concurrent programming language based on LISP. Concurrent LISP is designed to provide simple and flexible facilities for multi-process description without changing the original language features of LISP. This paper also describes the concurrent LISP interpreter which has been implemented on a FACOM M-200 at the Data Processing Center of Kyoto University. 19 references.

  13. Reference Capabilities for Concurrency Control

    OpenAIRE

    Castegren, Elias; Wrigstad, Tobias

    2016-01-01

    The proliferation of shared mutable state in object-oriented programming complicates software development as two seemingly unrelated operations may interact via an alias and produce unexpected results. In concurrent programming this manifests itself as data-races. Concurrent object-oriented programming further suffers from the fact that code that warrants synchronisation cannot easily be distinguished from code that does not. The burden is placed solely on the programmer to reason ab...

  14. Concurrent engineering: effective deployment strategies

    Directory of Open Access Journals (Sweden)

    Unny Menon

    1996-12-01

    Full Text Available This paper provides a comprehensive insight into current trends and developments in Concurrent Engineering for integrated development of products and processes with the goal of completing the entire cycle in a shorter time, at lower overall cost and with fewer engineering design changes after product release. The evolution and definition of Concurrent Engineering are addressed first, followed by a concise review of the following elements of the concurrent engineering approach to product development: Concept Development: The Front-End Process, identifying Customer Needs and Quality Function Deployment, Establishing Product Specifications, Concept Selection, Product Architecture, Design for Manufacturing, Effective Rapid Prototyping, and The Economics of Product Development. An outline of a computer-based tutorial developed by the authors and other graduate students funded by NASA ( accessible via the world-wide-web . is provided in this paper. A brief discussion of teamwork for successful concurrent engineering is included, t'ase histories of concurrent engineering implementation at North American and European companies are outlined with references to textbooks authored by Professor Menon and other writers. A comprehensive bibliography on concurrent engineering is included in the paper.

  15. Nonlinear optics

    International Nuclear Information System (INIS)

    Boyd, R.W.

    1992-01-01

    Nonlinear optics is the study of the interaction of intense laser light with matter. This book is a textbook on nonlinear optics at the level of a beginning graduate student. The intent of the book is to provide an introduction to the field of nonlinear optics that stresses fundamental concepts and that enables the student to go on to perform independent research in this field. This book covers the areas of nonlinear optics, quantum optics, quantum electronics, laser physics, electrooptics, and modern optics

  16. Nonlinear optics

    CERN Document Server

    Bloembergen, Nicolaas

    1996-01-01

    Nicolaas Bloembergen, recipient of the Nobel Prize for Physics (1981), wrote Nonlinear Optics in 1964, when the field of nonlinear optics was only three years old. The available literature has since grown by at least three orders of magnitude.The vitality of Nonlinear Optics is evident from the still-growing number of scientists and engineers engaged in the study of new nonlinear phenomena and in the development of new nonlinear devices in the field of opto-electronics. This monograph should be helpful in providing a historical introduction and a general background of basic ideas both for expe

  17. Optical Frequency Mixing in Periodically-Patterned and in Quasi-Periodically-Patterned Nonlinear media

    International Nuclear Information System (INIS)

    Arie, A.

    1999-01-01

    Nonlinear frequency mixing processes, e.g. second harmonic generation, sum and difference frequency generation, etc., require matching of the phases of the interacting waves. The traditional method to achieve it is by selecting a specific angle of propagation in a birefringent nonlinear crystal. The main limitation of the birefringent phase matching method stems from the fact that for many interesting interactions, the phase matching condition cannot be satisfied in a specific crystal. This obstacle can be removed by the technique of quasi-phase-matching (QPM), where the nonlinear coefficient of the material is modulated at a fixed spatial frequency that equals the wave-vector phase mismatch between the interacting waves. An important development in recent years is the ability to periodically reverse the sign of the nonlinear coefficient in ferroelectric crystals by applying a high electric field through a periodic electrode. Some recent QPM interactions in periodically-poled KTP that were recently achieved at Tel-Aviv University include continuous-wave optical parametric oscillations, as well as generation of tunable mid-infrared radiation by difference frequency generation. Periodic patterning of the nonlinear coefficient enables to phase match only a single interaction. It would be advantageous to further extend the applications of this technique in order to simultaneously satisfy several interactions on a single crystal. This cannot be usually achieved in a periodic pattern, however more sophisticated quasi-periodic structures can be designed in this case. An interesting analogy can be drawn between artificially-made quasi-periodically-patterned nonlinear crystals and quasi-crystals found in nature, in rapidly-cooled metallic alloys

  18. Modal abstractions of concurrent behavior

    DEFF Research Database (Denmark)

    Nielson, Flemming; Nanz, Sebastian; Nielson, Hanne Riis

    2011-01-01

    We present an effective algorithm for the automatic construction of finite modal transition systems as abstractions of potentially infinite concurrent processes. Modal transition systems are recognized as valuable abstractions for model checking because they allow for the validation as well...... as refutation of safety and liveness properties. However, the algorithmic construction of finite abstractions from potentially infinite concurrent processes is a missing link that prevents their more widespread usage for model checking of concurrent systems. Our algorithm is a worklist algorithm using concepts...... from abstract interpretation and operating upon mappings from sets to intervals in order to express simultaneous over- and underapprox-imations of the multisets of process actions available in a particular state. We obtain a finite abstraction that is 3-valued in both states and transitions...

  19. Managing Complexity of Control Software through Concurrency

    NARCIS (Netherlands)

    Hilderink, G.H.

    2005-01-01

    In this thesis, we are concerned with the development of concurrent software for embedded systems. The emphasis is on the development of control software. Embedded systems are concurrent systems whereby hardware and software communicate with the concurrent world. Concurrency is essential, which

  20. Concurrency & Asynchrony in Declarative Workflows

    DEFF Research Database (Denmark)

    Debois, Søren; Hildebrandt, Thomas; Slaats, Tijs

    2015-01-01

    of concurrency in DCR Graphs admits asynchronous execution of declarative workflows both conceptually and by reporting on a prototype implementation of a distributed declarative workflow engine. Both the theoretical development and the implementation is supported by an extended example; moreover, the theoretical....... In this paper, we pro- pose a notion of concurrency for declarative process models, formulated in the context of Dynamic Condition Response (DCR) graphs, and exploiting the so-called “true concurrency” semantics of Labelled Asynchronous Transition Systems. We demonstrate how this semantic underpinning...

  1. Nonlinear Science

    CERN Document Server

    Yoshida, Zensho

    2010-01-01

    This book gives a general, basic understanding of the mathematical structure "nonlinearity" that lies in the depths of complex systems. Analyzing the heterogeneity that the prefix "non" represents with respect to notions such as the linear space, integrability and scale hierarchy, "nonlinear science" is explained as a challenge of deconstruction of the modern sciences. This book is not a technical guide to teach mathematical tools of nonlinear analysis, nor a zoology of so-called nonlinear phenomena. By critically analyzing the structure of linear theories, and cl

  2. Nonlinear oscillations

    CERN Document Server

    Nayfeh, Ali Hasan

    1995-01-01

    Nonlinear Oscillations is a self-contained and thorough treatment of the vigorous research that has occurred in nonlinear mechanics since 1970. The book begins with fundamental concepts and techniques of analysis and progresses through recent developments and provides an overview that abstracts and introduces main nonlinear phenomena. It treats systems having a single degree of freedom, introducing basic concepts and analytical methods, and extends concepts and methods to systems having degrees of freedom. Most of this material cannot be found in any other text. Nonlinear Oscillations uses sim

  3. A Model for Concurrent Objects

    DEFF Research Database (Denmark)

    Sørensen, Morten U.

    1996-01-01

    We present a model for concurrent objects where obejcts interact by taking part in common events that are closely matched to form call-response pairs, resulting in resulting in rendez-vous like communications. Objects are built from primitive objects by parallel composition, encapsulation...

  4. Forward progress on GPU concurrency

    NARCIS (Netherlands)

    Donaldson, A.F.; Ketema, J.; Sorensen, T.; Wickerson, J.

    2017-01-01

    The tutorial at CONCUR will provide a practical overview of work undertaken over the last six years in the Multicore Programming Group at Imperial College London, and with collaborators internationally, related to understanding and reasoning about concurrency in software designed for acceleration on

  5. True Concurrency can be Traced

    DEFF Research Database (Denmark)

    Engberg, Uffe Henrik

    1990-01-01

    In this paper sets of labelled partial orders are employed as fundamental mathematical entities for modelling nondeterministic and concurrent processes thereby obtaining so-called noninterleaving semantics. Based on closures of sets of labelled partial orders, a simple algebraic language with ref...

  6. Relationships between models of concurrency

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Sassone, Vladimiro; Winskel, Glynn

    1994-01-01

    Models for concurrency can be classified with respect to the three relevant parameters: behaviour/system, interleaving/noninterleaving, linear/branching time. When modelling a process, a choice concerning such parameters corresponds to choosing the level of abstraction of the resulting semantics....

  7. Nonlinear systems

    CERN Document Server

    Palmero, Faustino; Lemos, M; Sánchez-Rey, Bernardo; Casado-Pascual, Jesús

    2018-01-01

    This book presents an overview of the most recent advances in nonlinear science. It provides a unified view of nonlinear properties in many different systems and highlights many  new developments. While volume 1 concentrates on mathematical theory and computational techniques and challenges, which are essential for the study of nonlinear science, this second volume deals with nonlinear excitations in several fields. These excitations can be localized and transport energy and matter in the form of breathers, solitons, kinks or quodons with very different characteristics, which are discussed in the book. They can also transport electric charge, in which case they are known as polarobreathers or solectrons. Nonlinear excitations can influence function and structure in biology, as for example, protein folding. In crystals and other condensed matter, they can modify transport properties, reaction kinetics and interact with defects. There are also engineering applications in electric lattices, Josephson junction a...

  8. Continuous variable tripartite entanglement from twin nonlinearities

    International Nuclear Information System (INIS)

    Olsen, M K; Bradley, A S

    2006-01-01

    In this work, we analyse and compare the continuous variable tripartite entanglement available from the use of two concurrent or cascaded χ (2) nonlinearities. We examine both idealized travelling-wave models and more experimentally realistic intracavity models, showing that tripartite entangled outputs are readily producible. These may be a useful resource for applications such as quantum cryptography and teleportation

  9. Data refinement for true concurrency

    Directory of Open Access Journals (Sweden)

    Brijesh Dongol

    2013-05-01

    Full Text Available The majority of modern systems exhibit sophisticated concurrent behaviour, where several system components modify and observe the system state with fine-grained atomicity. Many systems (e.g., multi-core processors, real-time controllers also exhibit truly concurrent behaviour, where multiple events can occur simultaneously. This paper presents data refinement defined in terms of an interval-based framework, which includes high-level operators that capture non-deterministic expression evaluation. By modifying the type of an interval, our theory may be specialised to cover data refinement of both discrete and continuous systems. We present an interval-based encoding of forward simulation, then prove that our forward simulation rule is sound with respect to our data refinement definition. A number of rules for decomposing forward simulation proofs over both sequential and parallel composition are developed.

  10. Concurrent Product & Supply Chain Creation

    DEFF Research Database (Denmark)

    Gubi, Ebbe

    it is a structural premise. We also know that logistics costs generally are estimated 15-20% of total product costs. Accordingly, it stands to reason that a company can reduce costs, and thereby gain an edge on its competitors, by tailoring the supply chain in question to an individual product or product family; i.......e. by creating Focused Supply Chains. At the same time, customer satisfaction can be increased. As a second means to achieving a better fit between product and supply chain, the firm can deploy Design for Logistics, the discipline of considering the supply chain during product creation. The thesis sets out...... and supply chains should be created concurrently and integrated. The concept of Concurrent Product & Supply Chain Creation is introduced, and the two main components Focused Supply Chains and Design For Logistics are explained and exemplified by use of Bang & Olufsen....

  11. Adding Concurrency to Smart Contracts

    OpenAIRE

    Dickerson, Thomas; Gazzillo, Paul; Herlihy, Maurice; Koskinen, Eric

    2017-01-01

    Modern cryptocurrency systems, such as Ethereum, permit complex financial transactions through scripts called smart contracts. These smart contracts are executed many, many times, always without real concurrency. First, all smart contracts are serially executed by miners before appending them to the blockchain. Later, those contracts are serially re-executed by validators to verify that the smart contracts were executed correctly by miners. Serial execution limits system throughput and fails ...

  12. Evaluation of concurrent peak responses

    International Nuclear Information System (INIS)

    Wang, P.C.; Curreri, J.; Reich, M.

    1983-01-01

    This report deals with the problem of combining two or more concurrent responses which are induced by dynamic loads acting on nuclear power plant structures. Specifically, the acceptability of using the square root of the sum of the squares (SRSS) value of peak values as the combined response is investigated. Emphasis is placed on the establishment of a simplified criterion that is convenient and relatively easy to use by design engineers

  13. PyCSP - controlled concurrency

    DEFF Research Database (Denmark)

    Vinter, Brian; Friborg, Rune Møllegaard; Bjørndalen, John Markus

    2010-01-01

    Producing readable and correct programs while at the same time taking advantage of multi-core architectures is a challenge. PyCSP is an implementation of Communicating Sequential Processes algebra (CSP) for the Python programming language, that take advantage of CSP's formal and verifiable approach...... to controlling concurrency and the readability of Python source code. We describe PyCSP, demonstrate it through examples and demonstrate how PyCSP compares to Pthreads in a master-worker benchmark....

  14. PyCSP - controlled concurrency

    DEFF Research Database (Denmark)

    Friborg, Rune Møllegaard; Vinter, Brian; Bjørndalen, John Markus

    Producing readable and correct programs while at the same time taking advantage of multi-core architectures is a challenge. PyCSP is an implementation of Communicating Sequential Processes algebra (CSP) for the Python programming language, taking advantage of CSP’s formal and verifiable approach...... to controlling concurrency and the readability of Python source code. We describe PyCSP, demonstrate it through examples and demonstrate how PyCSP compares to Pthreads using a benchmark....

  15. Nonlinear optics

    CERN Document Server

    Boyd, Robert W

    2013-01-01

    Nonlinear Optics is an advanced textbook for courses dealing with nonlinear optics, quantum electronics, laser physics, contemporary and quantum optics, and electrooptics. Its pedagogical emphasis is on fundamentals rather than particular, transitory applications. As a result, this textbook will have lasting appeal to a wide audience of electrical engineering, physics, and optics students, as well as those in related fields such as materials science and chemistry.Key Features* The origin of optical nonlinearities, including dependence on the polarization of light* A detailed treatment of the q

  16. Concurrent chemoradiation for vaginal cancer.

    Directory of Open Access Journals (Sweden)

    David T Miyamoto

    Full Text Available BACKGROUND: It is not known whether the addition of chemotherapy to radiation therapy improves outcomes in primary vaginal cancer. Here, we review clinical outcomes in patients with primary vaginal cancer treated with radiation therapy (RT or concurrent chemoradiation therapy (CRT. METHODS: Seventy-one patients with primary vaginal cancer treated with definitive RT with or without concurrent chemotherapy at a single institution were identified and their records reviewed. A total of 51 patients were treated with RT alone; 20 patients were treated with CRT. Recurrences were analyzed. Overall survival (OS and disease-free survival (DFS rates were estimated using the Kaplan-Meier method. Cox regression analysis was performed. RESULTS: The median age at diagnosis was 61 years (range, 18-92 years and the median follow-up time among survivors was 3.0 years. Kaplan-Meier estimates for OS and DFS differed significantly between the RT and CRT groups (3-yr OS = 56% vs. 79%, log-rank p = 0.037; 3-yr DFS = 43% vs. 73%, log-rank p = 0.011. Twenty-three patients (45% in the RT group had a relapse at any site compared to 3 (15% in the CRT group (p = 0.027. With regard to the sites of first relapse, 10 patients (14% had local only, 4 (6% had local and regional, 9 (13% had regional only, 1 (1% had regional and distant, and 2 (3% had distant only relapse. On univariate analysis, the use of concurrent chemotherapy, FIGO stage, tumor size, and date of diagnosis were significant predictors of DFS. On multivariate analysis, the use of concurrent chemotherapy remained a significant predictor of DFS (hazard ratio 0.31 (95% CI, 0.10-0.97; p = 0.04. CONCLUSIONS: Vaginal cancer results in poor outcomes. Adequate radiation dose is essential to ensure curative management. Concurrent chemotherapy should be considered for vaginal cancer patients.

  17. Concurrence classes for general pure multipartite states

    International Nuclear Information System (INIS)

    Heydari, Hoshang

    2005-01-01

    We propose concurrence classes for general pure multipartite states based on an orthogonal complement of a positive operator-valued measure on quantum phase. In particular, we construct W m class, GHZ m , and GHZ m-1 class concurrences for general pure m-partite states. We give explicit expressions for W 3 and GHZ 3 class concurrences for general pure three-partite states and for W 4 , GHZ 4 and GHZ 3 class concurrences for general pure four-partite states

  18. Simple concurrent garbage collection almost without synchronization

    NARCIS (Netherlands)

    Hesselink, Wim H.; Lali, M.I.

    We present two simple mark and sweep algorithms, A and B, for concurrent garbage collection by a single collector running concurrently with a number of mutators that concurrently modify shared data. Both algorithms are based on the ideas of Ben-Ari's classical algorithm for on-the-fly garbage

  19. Nonlinear systems

    National Research Council Canada - National Science Library

    Drazin, P. G

    1992-01-01

    This book is an introduction to the theories of bifurcation and chaos. It treats the solution of nonlinear equations, especially difference and ordinary differential equations, as a parameter varies...

  20. Nonlinear analysis

    CERN Document Server

    Gasinski, Leszek

    2005-01-01

    Hausdorff Measures and Capacity. Lebesgue-Bochner and Sobolev Spaces. Nonlinear Operators and Young Measures. Smooth and Nonsmooth Analysis and Variational Principles. Critical Point Theory. Eigenvalue Problems and Maximum Principles. Fixed Point Theory.

  1. Steps in Modular Specifications for Concurrent Modules

    DEFF Research Database (Denmark)

    Da Rocha Pinto, Pedro; Dinsdale-Young, Thomas; Gardner, Philippa

    2015-01-01

    The specification of a concurrent program module is a difficult problem. The specifications must be strong enough to enable reasoning about the intended clients without reference to the underlying module implementation. We survey a range of verification techniques for specifying concurrent module......, in particular highlighting four key concepts: auxiliary state, interference abstraction, resource ownership and atomicity. We show how these concepts combine to provide powerful approaches to specifying concurrent modules.......The specification of a concurrent program module is a difficult problem. The specifications must be strong enough to enable reasoning about the intended clients without reference to the underlying module implementation. We survey a range of verification techniques for specifying concurrent modules...

  2. Specifying and Verifying Concurrent Programs.

    Science.gov (United States)

    1985-02-01

    for Verification and Specification of Concurrent Systems, held in La - Colle - Sur - Loup , France in October, 1984. Work Supported in part by the National...Proc. ACM Symposium on Princi- 0 ples of Programming Languages, Las Vegas, (January 1980), 251-261. [7] J. V. Guttag and J. J. Horning. An Introduction...names in ’V(S). However, the two formulas behave differently under a renaming mapping p. In particu- lar. p(Vv :A( LA )) equals Vv :p(A(v)), so the

  3. Multiprocessor systems and their concurrency

    Energy Technology Data Exchange (ETDEWEB)

    Starke, P H

    1984-01-01

    A multiprocessor system can be considered as a collection of finite automata which communicate over channels or shared memory units. The behaviour of such a system can be described by a semilanguage. This approach allows to define a numerical measure for the concurrency of multiprocessor systems and of distributed systems. This measure is characterized algebraically and the reconfiguration problem asking for an algorithm to construct an l-processor system which is equivalent to a given n-processor system is solved in the paper. 6 references.

  4. Concurrency at work with Go

    CERN Document Server

    CERN. Geneva

    2017-01-01

    High Energy and Nuclear Physics (HENP) libraries are now required to be increasingly multi-thread-safe, if not multi-thread-friendly and multi-threaded. This is usually done using the new constructs and library components offered by the C++11 and C++14 standards. These components are however quite low-level (threads, mutexes, locks, ...) and hard to use and compose, or easy to misuse. However, Go -- a somewhat new language -- provides a set of better building blocks for tackling concurrency: goroutines and channels. This language is now used by the cloud industry at large; docker/moby, rkt, Kubernetes, OpenShift, etc... are obvious flagships for Go. It is also used in other interesting places like SpaceX's telemetry monitoring system and in the New York Times', YouTube's or Disney's content delivery infrastructures. In this talk, we will describe the building blocks of Go and see how they are combined to easily create concurrent programs that grow with grace, are fast to compile and deploy, but also easy to...

  5. Patients survey after concurrent chemoradiotherapy

    International Nuclear Information System (INIS)

    Shimane, Toshikazku; Egawa, Syunya; Mori, Tomoaki; Ono, Tomohiro; Monden, Tetsuya; Kobayashi, Sei; Sanbe, Takeyuki; Suzaki, Harumi

    2010-01-01

    Concurrent chemoradiotherapy for cancer of head and neck is becoming more popular as the treatment of choice. It is considered to maintain the quality of life (QOL) of patients better than operative treatments in terms of preserving the functions, organs, and figure, but recently we cannot necessarily say that it maintains the QOL of patients better than operative treatments because its complications after therapy disturb daily life. We report the results of a questionnaire survey about complications after therapy, problems during therapy, improvements, and satisfaction level directed at patients with cancer of the head and neck who received Concurrent chemoradiotherapy for the purpose of ascertaining if patients can actually maintain their QOL after therapy. As a result, the most controversial problem was mouth dryness, but the symptom improved as the follow-up duration got longer. As for the satisfaction level, 'very-satisfied' and 'almost-satisfied' were more than 90%, so we concluded that the QOL of patients is maintained after therapy, while there are still improvements to be made. We also concluded that we should continue to make improvement and try to improve the QOL of patients during and after therapy. (author)

  6. Nonlinear optimization

    CERN Document Server

    Ruszczynski, Andrzej

    2011-01-01

    Optimization is one of the most important areas of modern applied mathematics, with applications in fields from engineering and economics to finance, statistics, management science, and medicine. While many books have addressed its various aspects, Nonlinear Optimization is the first comprehensive treatment that will allow graduate students and researchers to understand its modern ideas, principles, and methods within a reasonable time, but without sacrificing mathematical precision. Andrzej Ruszczynski, a leading expert in the optimization of nonlinear stochastic systems, integrates the theory and the methods of nonlinear optimization in a unified, clear, and mathematically rigorous fashion, with detailed and easy-to-follow proofs illustrated by numerous examples and figures. The book covers convex analysis, the theory of optimality conditions, duality theory, and numerical methods for solving unconstrained and constrained optimization problems. It addresses not only classical material but also modern top...

  7. Concurrent systems and time synchronization

    Science.gov (United States)

    Burgin, Mark; Grathoff, Annette

    2018-05-01

    In the majority of scientific fields, system dynamics is described assuming existence of unique time for the whole system. However, it is established theoretically, for example, in relativity theory or in the system theory of time, and validated experimentally that there are different times and time scales in a variety of real systems - physical, chemical, biological, social, etc. In spite of this, there are no wide-ranging scientific approaches to exploration of such systems. Therefore, the goal of this paper is to study systems with this property. We call them concurrent systems because processes in them can go, events can happen and actions can be performed in different time scales. The problem of time synchronization is specifically explored.

  8. Nutritional strategies to support concurrent training.

    Science.gov (United States)

    Perez-Schindler, Joaquin; Hamilton, D Lee; Moore, Daniel R; Baar, Keith; Philp, Andrew

    2015-01-01

    Concurrent training (the combination of endurance exercise to resistance training) is a common practice for athletes looking to maximise strength and endurance. Over 20 years ago, it was first observed that performing endurance exercise after resistance exercise could have detrimental effects on strength gains. At the cellular level, specific protein candidates have been suggested to mediate this training interference; however, at present, the physiological reason(s) behind the concurrent training effect remain largely unknown. Even less is known regarding the optimal nutritional strategies to support concurrent training and whether unique nutritional approaches are needed to support endurance and resistance exercise during concurrent training approaches. In this review, we will discuss the importance of protein supplementation for both endurance and resistance training adaptation and highlight additional nutritional strategies that may support concurrent training. Finally, we will attempt to synergise current understanding of the interaction between physiological responses and nutritional approaches into practical recommendations for concurrent training.

  9. Rain VM: Portable Concurrency through Managing Code

    OpenAIRE

    Brown, Neil C.C.

    2006-01-01

    A long-running recent trend in computer programming is the growth in popularity of virtual machines. However, few have included good support for concurrency - a natural mechanism in the Rain programming language. This paper details the design and implementation of a secure virtual machine with support for concurrency, which enables portability of concurrent programs. Possible implementation ideas of many-to-many threading models for the virtual machine kernel are discussed, and initial benchm...

  10. Concurrence of three Jaynes-Cummings systems

    Science.gov (United States)

    Qiang, Wen-Chao; Sun, Guo-Hua; Dong, Qian; Camacho-Nieto, Oscar; Dong, Shi-Hai

    2018-04-01

    We apply genuine multipartite concurrence to investigate entanglement properties of three Jaynes-Cummings systems. Three atoms are initially put in GHZ-like state and locally interact with three independent cavities, respectively. We present analytical concurrence expressions for various subsystems including three-atom, three-cavity and some atom-cavity mixed systems. We also examine the global system and illustrate the evolution of its concurrence. Except for the sudden death of entanglement, we find for some initial entanglement parameter θ , the concurrence of the global system may maintain unchanged in some time intervals.

  11. How does concurrent sourcing affect performance?

    DEFF Research Database (Denmark)

    Mols, Niels Peter

    2010-01-01

    be modelled. The propositions and discussion offer researchers a starting-point for further research. Practical implications – The propositions that are developed suggest that managers should consider using concurrent sourcing when they face problems caused by volume uncertainty, technological uncertainty....../methodology/approach – Based on transaction cost, agency, neoclassical economic, knowledge-based, and resource-based theory, it is proposed to show how concurrent sourcing affects performance. Findings – The paper argues that concurrent sourcing improves performance when firms face a combination of volume uncertainty...... how concurrent sourcing affects performance of the market and the hierarchy....

  12. A Reference Framework for Concurrent Engineering

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Considering the diversity of methods and tools offered to concurrent engineering, the aspects playing important roles in the concurrent engineering c ontext have been pinpointed as being four core elements which are Activity, Meth od, Object and Information. Based on these four elements, a reference framework called AMOI is proposed to be the guideline for the systematic concurrent produc t design. Using the AMOI reference framework, concurrent product development sys tem can be structured into four function models (including the activity model, m ethod model, object model and information model) which are interconnected with e ach other.

  13. Short-term Mobility and Increased Partnership Concurrency among Men in Zimbabwe.

    Directory of Open Access Journals (Sweden)

    Susan Cassels

    Full Text Available Migration has long been understood as an underlying factor for HIV transmission, and sexual partner concurrency has been increasingly studied as an important component of HIV transmission dynamics. However, less work has examined the role of short-term mobility in sexual partner concurrency using a network approach. Short-term mobility may be a risk for HIV for the migrant's partner as well either through the partner's risk behaviors while the migrant is away, such as the partner having additional partners, or via exposure to the return migrant.Using data from the 2010-11 Zimbabwe Demographic and Health Survey, weighted generalized linear regression models were used to investigate the associations between short-term mobility and partnership concurrency at the individual and partnership levels.At the individual level, we find strong evidence of an association between short-term mobility and concurrency. Men who traveled were more likely to have concurrent partnerships compared to men who did not travel and the relationship was non-linear: each trip was associated with a 2% higher probability of concurrency, with a diminishing risk at 60 trips (p<0.001. At the partnership level, short-term mobility by the male only or both partners was associated with male concurrency. Couples in which the female only traveled exhibited less male concurrency.Short-term mobility has the ability to impact population-level transmission dynamics by facilitating partnership concurrency and thus onward HIV transmission. Short-term migrants may be an important population to target for HIV testing, treatment, or social and behavioral interventions to prevent the spread of HIV.

  14. Plant management in concurrent engineering

    International Nuclear Information System (INIS)

    Haubensack, D.; Malvache, P.; Valleix, P.

    1997-01-01

    The ImagIn project consist in a method and a set of computer tools apt to bring perceptible and assessable improvements in the operational safety of a nuclear plant. Its aim is to design an information system that would maintain a highly detailed computerised representation of a nuclear plant, in its initial state and throughout its in-service life. It is not a tool to drive or help driving the nuclear plant, but a tool that manages concurrent operations that modify the plant configuration in a very general way (maintenance for example). The configuration of the plant, as well as rules and constraints about it, are described in a object-oriented, knowledge database, which is built using a generic ImagIn meta-model based on the semantical network theory. An inference engine works on this database and is connected to reality through interfaces to operators and captors on the installation; it verifies constantly in real-time the consistency of the database according to its inner rules, and reports eventual problems to concerned operators. A special effort is made on interfaces to provide natural and intuitive tools (using virtual reality, natural language, voice recognition and synthesis). A laboratory application on a fictive but realistic installation already exist and is used to simulate various test and scenari. A real application is being constructed on SILOE, an experimental reactor of the CEA. (authors)

  15. Multiparty Compatibility for Concurrent Objects

    Directory of Open Access Journals (Sweden)

    Roly Perera

    2016-06-01

    Full Text Available Objects and actors are communicating state machines, offering and consuming different services at different points in their lifecycle. Two complementary challenges arise when programming such systems. When objects interact, their state machines must be "compatible", so that services are requested only when they are available. Dually, when objects refine other objects, their state machines must be "compliant", so that services are honoured whenever they are promised. In this paper we show how the idea of multiparty compatibility from the session types literature can be applied to both of these problems. We present an untyped language in which concurrent objects are checked automatically for compatibility and compliance. For simple objects, checking can be exhaustive and has the feel of a type system. More complex objects can be partially validated via test cases, leading to a methodology closer to continuous testing. Our proof-of-concept implementation is limited in some important respects, but demonstrates the potential value of the approach and the relationship to existing software development practices.

  16. Verified compilation of Concurrent Managed Languages

    Science.gov (United States)

    2017-11-01

    Communications Division Information Directorate This report is published in the interest of scientific and technical information exchange, and its...271, 2007. [85] Viktor Vafeiadis. Modular fine-grained concurrency verification. Technical Report UCAM-CL-TR- 726, University of Cambridge, Computer...VERIFIED COMPILATION OF CONCURRENT MANAGED LANGUAGES PURDUE UNIVERSITY NOVEMBER 2017 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE

  17. Ecological association between HIV and concurrency point ...

    African Journals Online (AJOL)

    Ecological association between HIV and concurrency point-prevalence in South Africa's ethnic groups. Chris Kenyon. Abstract. HIV prevalence between different ethnic groups within South Africa exhibits considerable variation. Numerous authors believe that elevated sexual partner concurrency rates are important in the ...

  18. A Temporal Concurrent Constraint Programming Calculus

    DEFF Research Database (Denmark)

    Palamidessi, Catuscia; Valencia Posso, Frank Darwin

    2001-01-01

    The tcc model is a formalism for reactive concurrent constraint programming. In this paper we propose a model of temporal concurrent constraint programming which adds to tcc the capability of modeling asynchronous and non-deterministic timed behavior. We call this tcc extension the ntcc calculus...

  19. New concurrent iterative methods with monotonic convergence

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Qingchuan [Michigan State Univ., East Lansing, MI (United States)

    1996-12-31

    This paper proposes the new concurrent iterative methods without using any derivatives for finding all zeros of polynomials simultaneously. The new methods are of monotonic convergence for both simple and multiple real-zeros of polynomials and are quadratically convergent. The corresponding accelerated concurrent iterative methods are obtained too. The new methods are good candidates for the application in solving symmetric eigenproblems.

  20. Nonlinear Elliptic Differential Equations with Multivalued Nonlinearities

    Indian Academy of Sciences (India)

    In this paper we study nonlinear elliptic boundary value problems with monotone and nonmonotone multivalued nonlinearities. First we consider the case of monotone nonlinearities. In the first result we assume that the multivalued nonlinearity is defined on all R R . Assuming the existence of an upper and of a lower ...

  1. Fabrication and Characterization of Linear and Nonlinear Photonic Devices in Fused Silica by Femtosecond Laser Writing

    Science.gov (United States)

    Ng, Jason Clement

    Femtosecond laser processing is a flexible, three-dimensional (3D) fabrication technique used to make integrated low-loss photonic devices in fused silica. My work expanded the suite of available optical devices through the design and optimization of linear optical components such as low-loss (70-nm spectral window. My work further complemented femtosecond laser processing with the development of nonlinear device capabilities. While thermal poling is a well known process, significant challenges had restricted the development of nonlinear devices in fused silica. The laser writing process would erase the induced nonlinearity (erasing) while a written waveguide core acted as a barrier to the thermal poling process (blocking). Using second harmonic (SH) microscopy, the effectiveness of thermal poling on laser-written waveguides was systematically analyzed leading to the technique of "double poling", which effectively overcomes the two challenges of erasing and blocking. In this new process the substrate is poled before and after waveguide writing to restore the induced nonlinearity within the vicinity of the waveguide to enable effective poling for inducing a second-order nonlinearity (SON) in fused silica. A new flexible, femtosecond laser based erasure process was also developed to enable quasi-phase matching and to form arbitrarily chirped gratings. Following this result, second harmonic generation (SHG) in a quasiphase-matched (QPM) femtosecond laser written waveguide device was demonstrated. SHG in a chirped QPM structure was also demonstrated to illustrate the flexibility of the femtosecond laser writing technique. These are the first demonstration of frequency doubling in an all-femtosecond-laser-written structure. A maximum SHG conversion efficiency of 1.3 +/- 0.1x10 -11/W-cm-2 was achieved for the fundamental wavelength of 1552.8 nm with a phase-matching bandwidth of 4.4 nm for a 10.0-mm-long waveguide. For a shorter sample, an effective SON of chi(2) = 0

  2. Quadripartite continuous-variable entanglement via quadruply concurrent down-conversion

    International Nuclear Information System (INIS)

    Midgley, S. L. W.; Olsen, M. K.; Bradley, A. S.; Pfister, O.

    2010-01-01

    We investigate an experimentally feasible intracavity coupled down-conversion scheme to generate quadripartite entanglement using concurrent nonlinearities. We verify that quadripartite entanglement is present in this system by calculating the output fluctuation spectra and then considering violations of optimized inequalities of the van Loock-Furusawa type. The entanglement characteristics both above and below the oscillation threshold are considered. We also present analytic solutions for the quadrature operators and the van Loock-Furusawa correlations in the undepleted pump approximation.

  3. The Caltech Concurrent Computation Program - Project description

    Science.gov (United States)

    Fox, G.; Otto, S.; Lyzenga, G.; Rogstad, D.

    1985-01-01

    The Caltech Concurrent Computation Program wwhich studies basic issues in computational science is described. The research builds on initial work where novel concurrent hardware, the necessary systems software to use it and twenty significant scientific implementations running on the initial 32, 64, and 128 node hypercube machines have been constructed. A major goal of the program will be to extend this work into new disciplines and more complex algorithms including general packages that decompose arbitrary problems in major application areas. New high-performance concurrent processors with up to 1024-nodes, over a gigabyte of memory and multigigaflop performance are being constructed. The implementations cover a wide range of problems in areas such as high energy and astrophysics, condensed matter, chemical reactions, plasma physics, applied mathematics, geophysics, simulation, CAD for VLSI, graphics and image processing. The products of the research program include the concurrent algorithms, hardware, systems software, and complete program implementations.

  4. MLIP: A Concurrent Approach for Clipping Indexing

    OpenAIRE

    Majoju Ravinder; R.Vijay Prakash

    2011-01-01

    Multidimensional databases are beginning to be used in a wide range of applications. To meet this fast-growing demand, the R-tree family is being applied to support fast access to multidimensional data, for which the R+-tree exhibits outstanding search performance. In order to support efficient concurrent access in multi-user environments, concurrency control mechanisms for multidimensional indexing have been proposed. However, these mechanisms cannot be directly applied to the R+-tree becaus...

  5. Nonlinear Elasticity

    Science.gov (United States)

    Fu, Y. B.; Ogden, R. W.

    2001-05-01

    This collection of papers by leading researchers in the field of finite, nonlinear elasticity concerns itself with the behavior of objects that deform when external forces or temperature gradients are applied. This process is extremely important in many industrial settings, such as aerospace and rubber industries. This book covers the various aspects of the subject comprehensively with careful explanations of the basic theories and individual chapters each covering a different research direction. The authors discuss the use of symbolic manipulation software as well as computer algorithm issues. The emphasis is placed firmly on covering modern, recent developments, rather than the very theoretical approach often found. The book will be an excellent reference for both beginners and specialists in engineering, applied mathematics and physics.

  6. Nonlinear resonances

    CERN Document Server

    Rajasekar, Shanmuganathan

    2016-01-01

    This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...

  7. Characterizing Distributed Concurrent Engineering Teams: A Descriptive Framework for Aerospace Concurrent Engineering Design Teams

    Science.gov (United States)

    Chattopadhyay, Debarati; Hihn, Jairus; Warfield, Keith

    2011-01-01

    As aerospace missions grow larger and more technically complex in the face of ever tighter budgets, it will become increasingly important to use concurrent engineering methods in the development of early conceptual designs because of their ability to facilitate rapid assessments and trades in a cost-efficient manner. To successfully accomplish these complex missions with limited funding, it is also essential to effectively leverage the strengths of individuals and teams across government, industry, academia, and international agencies by increased cooperation between organizations. As a result, the existing concurrent engineering teams will need to increasingly engage in distributed collaborative concurrent design. This paper is an extension of a recent white paper written by the Concurrent Engineering Working Group, which details the unique challenges of distributed collaborative concurrent engineering. This paper includes a short history of aerospace concurrent engineering, and defines the terms 'concurrent', 'collaborative' and 'distributed' in the context of aerospace concurrent engineering. In addition, a model for the levels of complexity of concurrent engineering teams is presented to provide a way to conceptualize information and data flow within these types of teams.

  8. [Nonlinear magnetohydrodynamics

    International Nuclear Information System (INIS)

    1994-01-01

    Resistive MHD equilibrium, even for small resistivity, differs greatly from ideal equilibrium, as do the dynamical consequences of its instabilities. The requirement, imposed by Faraday's law, that time independent magnetic fields imply curl-free electric fields, greatly restricts the electric fields allowed inside a finite-resistivity plasma. If there is no flow and the implications of the Ohm's law are taken into account (and they need not be, for ideal equilibria), the electric field must equal the resistivity times the current density. The vanishing of the divergence of the current density then provides a partial differential equation which, together with boundary conditions, uniquely determines the scalar potential, the electric field, and the current density, for any given resistivity profile. The situation parallels closely that of driven shear flows in hydrodynamics, in that while dissipative steady states are somewhat more complex than ideal ones, there are vastly fewer of them to consider. Seen in this light, the vast majority of ideal MHD equilibria are just irrelevant, incapable of being set up in the first place. The steady state whose stability thresholds and nonlinear behavior needs to be investigated ceases to be an arbitrary ad hoc exercise dependent upon the whim of the investigator, but is determined by boundary conditions and choice of resistivity profile

  9. Nonlinear beam mechanics

    NARCIS (Netherlands)

    Westra, H.J.R.

    2012-01-01

    In this Thesis, nonlinear dynamics and nonlinear interactions are studied from a micromechanical point of view. Single and doubly clamped beams are used as model systems where nonlinearity plays an important role. The nonlinearity also gives rise to rich dynamic behavior with phenomena like

  10. Concurrent sourcing and external supplier opportunism

    DEFF Research Database (Denmark)

    Mols, Niels Peter

    costs of opportunism are determined as a product of four factors. The four factors are: likelihood of discovering supplier opportunism, buyer’s internalized quantity as reaction to supplier opportunism, asset specificity of external supplier’s investments, and multiplicator effects. Each......When a firm simultaneously makes and buys the same components then the firm uses concurrent sourcing. This paper presents an agency model for explaining how and when concurrent sourcing reduces the likelihood of external supplier opportunism. In the proposed model, the external supplier’s expected...... of these factors are explained and discussed in the paper. The paper ends by offering a number of theoretical and managerial implications....

  11. Notes on Timed Concurrent Constraint Programming

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Valencia, Frank D.

    2004-01-01

    and program reactive systems. This note provides a comprehensive introduction to the background for and central notions from the theory of tccp. Furthermore, it surveys recent results on a particular tccp calculus, ntcc, and it provides a classification of the expressive power of various tccp languages.......A constraint is a piece of (partial) information on the values of the variables of a system. Concurrent constraint programming (ccp) is a model of concurrency in which agents (also called processes) interact by telling and asking information (constraints) to and from a shared store (a constraint...

  12. Emotion as Opportunity: Reflections on Multiple Concurrent ...

    African Journals Online (AJOL)

    Partner reduction has been shown to be one of the most important aspects of any programme that seeks to contain the spread of HIV. In South Africa, however, multiple concurrent sexual partnerships are a common feature of township life for young people, especially young men. Following on from XXXXX's (2009) study on ...

  13. Declarative interpretations of session-based concurrency

    DEFF Research Database (Denmark)

    Cano, Mauricio; Rueda, Camilo; López-Acosta, Hugo-Andrés

    2015-01-01

    Session-based concurrency is a type-based approach to the analysis of communication-intensive systems. Correct behavior in these systems may be specified in an operational or declarative style: the former defines how interactions are structured; the latter defines governing conditions...

  14. Integrated concurrent utilization quality review, Part one.

    Science.gov (United States)

    Caterinicchio, R P

    1987-01-01

    This article is the first of a two-part series which argues for the concurrent management of the appropriateness, necessity, and quality of patient care. Intensifying scrutiny by the credentialing groups, the PROs and all third-party payors underscores the vital need to implement cost-effective information systems which integrate the departmentalized functions of patient-physician profiling, DRG case-mix analyses, length of stay monitoring, pre-admission/admission and continued stay review, discharge planning, risk management, incident reporting and quality review. In the domain of physician performance regarding admitting and practice patterns, the ability to exercise concurrent utilization-quality review means early detection and prevention of events which would otherwise result in denials of payment and/or compromised patient care. Concurrent utilization-quality review must, by definition, be managerially invasive and focused; hence, it is integral to maintaining the integrity of the services and product lines offered by the provider. In fact, if PPO status is a marketing agenda, then the institutional objectives of cost-effectiveness, productivity, value, and competitiveness can only be achieved through concurrent utilization-quality review.

  15. An Evaluation of Concurrent Priority Queue Algorithms

    Science.gov (United States)

    1991-02-01

    path pronlem are testedi A! -S7 ?o An Evaluation of Concurrent Priority Queue Algorithms bv Qin Huang BS. Uiversity - of Science andi Technology of China...who have always supported me through my entire career and made my life more enjoyable. This research was supported in part by the Advanced Research

  16. Concurrent Engineering in seafood product development

    DEFF Research Database (Denmark)

    Jonsdottir, Stella; Vesterager, Johan; Børresen, Torger

    1998-01-01

    benefit from the CE approach which can support product developers to provide concurrent specifications for raw materials, ingredients, packaging, and production methods. The approach involves the use of product models from which line extensions are more easily generated than by use of customary stepwise...... techniques. it is anticipated that other food industries also can benefit from the more simultaneous approach...

  17. Concurrency meets probability: theory and practice (abstract)

    NARCIS (Netherlands)

    Katoen, Joost P.

    Treating random phenomena in concurrency theory has a long tradition. Petri nets [18, 10] and process algebras [14] have been extended with probabilities. The same applies to behavioural semantics such as strong and weak (bi)simulation [1], and testing pre-orders [5]. Beautiful connections between

  18. On run-time exploitation of concurrency

    NARCIS (Netherlands)

    Holzenspies, P.K.F.

    2010-01-01

    The `free' speed-up stemming from ever increasing processor speed is over. Performance increase in computer systems can now only be achieved through parallelism. One of the biggest challenges in computer science is how to map applications onto parallel computers. Concurrency, seen as the set of

  19. Concurrent Design of Embedded Control Software

    NARCIS (Netherlands)

    Groothuis, M.A.; Frijns, Raymond; Voeten, Jeroen; Broenink, Johannes F.; Margaria, T.; Padberg, J.; Taentzer, G.; Levendovszky, T.; Lengyel, L.; Karsai, G.; Hardebolle, C.

    2009-01-01

    Embedded software design for mechatronic systems is becoming an increasingly time-consuming and error-prone task. In order to cope with the heterogeneity and complexity, a systematic model-driven design approach is needed, where several parts of the system can be designed concurrently. There is

  20. Angelic semantics of fine-grained concurrency

    OpenAIRE

    Dan R. Ghica; Andrzej S. Murawski

    2008-01-01

    We introduce a game model for an Algol-like programming language with primitives for parallel composition and synchronization on semaphores. The semantics is based on a simplified version of Hyland–Ong-style games and it emphasizes the intuitive connection between the concurrent nature of games and that of computation. The model is fully abstract for may-equivalence.

  1. A body sensor platform for concurrent applications

    NARCIS (Netherlands)

    Bui, T.V.; Verhoeven, R.; Lukkien, J.J.

    2012-01-01

    This paper presents a Body Sensor Platform supporting concurrent applications that share resources and data. Concerns are application isolation, data privacy and platform trustworthiness in view of dynamic loading of applications. A prototype has been built on commercial-off-the-shelf hardware. The

  2. 29 CFR 502.17 - Concurrent actions.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Concurrent actions. 502.17 Section 502.17 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS ENFORCEMENT OF CONTRACTUAL OBLIGATIONS FOR TEMPORARY ALIEN AGRICULTURAL WORKERS ADMITTED UNDER SECTION 218 OF THE IMMIGRATION...

  3. 29 CFR 501.17 - Concurrent actions.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Concurrent actions. 501.17 Section 501.17 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR REGULATIONS ENFORCEMENT OF CONTRACTUAL OBLIGATIONS FOR TEMPORARY ALIEN AGRICULTURAL WORKERS ADMITTED UNDER SECTION 218 OF THE IMMIGRATION...

  4. Concurrent analysis: towards generalisable qualitative research.

    Science.gov (United States)

    Snowden, Austyn; Martin, Colin R

    2011-10-01

    This study develops an original method of qualitative analysis coherent with its interpretivist principles. The objective is to increase the likelihood of achieving generalisability and so improve the chance of the findings being translated into practice. Good qualitative research depends on coherent analysis of different types of data. The limitations of existing methodologies are first discussed to justify the need for a novel approach. To illustrate this approach, primary evidence is presented using the new methodology. The primary evidence consists of a constructivist grounded theory of how mental health nurses with prescribing authority integrate prescribing into practice. This theory is built concurrently from interviews, reflective accounts and case study data from the literature. Concurrent analysis. Ten research articles and 13 semi-structured interviews were sampled purposively and then theoretically and analysed concurrently using constructivist grounded theory. A theory of the process of becoming competent in mental health nurse prescribing was generated through this process. This theory was validated by 32 practising mental health nurse prescribers as an accurate representation of their experience. The methodology generated a coherent and generalisable theory. It is therefore claimed that concurrent analysis engenders consistent and iterative treatment of different sources of qualitative data in a manageable manner. This process supports facilitation of the highest standard of qualitative research. Concurrent analysis removes the artificial delineation of relevant literature from other forms of constructed data. This gives researchers clear direction to treat qualitative data consistently raising the chances of generalisability of the findings. Raising the generalisability of qualitative research will increase its chances of informing clinical practice. © 2010 Blackwell Publishing Ltd.

  5. Safety effects of exclusive and concurrent signal phasing for pedestrian crossing.

    Science.gov (United States)

    Zhang, Yaohua; Mamun, Sha A; Ivan, John N; Ravishanker, Nalini; Haque, Khademul

    2015-10-01

    This paper describes the estimation of pedestrian crash count and vehicle interaction severity prediction models for a sample of signalized intersections in Connecticut with either concurrent or exclusive pedestrian phasing. With concurrent phasing, pedestrians cross at the same time as motor vehicle traffic in the same direction receives a green phase, while with exclusive phasing, pedestrians cross during their own phase when all motor vehicle traffic on all approaches is stopped. Pedestrians crossing at each intersection were observed and classified according to the severity of interactions with motor vehicles. Observation intersections were selected to represent both types of signal phasing while controlling for other physical characteristics. In the nonlinear mixed models for interaction severity, pedestrians crossing on the walk signal at an exclusive signal experienced lower interaction severity compared to those crossing on the green light with concurrent phasing; however, pedestrians crossing on a green light where an exclusive phase was available experienced higher interaction severity. Intersections with concurrent phasing have fewer total pedestrian crashes than those with exclusive phasing but more crashes at higher severity levels. It is recommended that exclusive pedestrian phasing only be used at locations where pedestrians are more likely to comply. Copyright © 2015. Published by Elsevier Ltd.

  6. Transactions Concurrency Control in Web Service Environment

    DEFF Research Database (Denmark)

    Alrifai, Mohammad; Dolog, Peter; Nejdl, Wolfgang

    2006-01-01

    an engineering point of view as it does not change the way consumers or clients of web services have to be programmed. Furthermore, it avoids direct communication between transaction coordinators which preserves security by keeping the information about business transactions restricted to the coordinators which......Business transactions in web service environments run with relaxed isolation and atomicity property. In such environments, transactions can commit and roll back independently on each other. Transaction management has to reflect this issue and address the problems which result for example from...... concurrent access to web service resources and data. In this paper we propose an extension to the WS-Transaction Protocol which ensures the consistency of the data when independent business transactions access the data concurrently under the relaxed transaction properties. Our extension is based...

  7. Authentic And Concurrent Evaluation-refining

    DEFF Research Database (Denmark)

    Eriksson, Carina Ihlström; Åkesson, Maria; Kautz, Karlheinz

    2011-01-01

    This paper addresses the need for more detailed accounts for evaluation in design science research literature. By revisiting a design project regarding the future e-newspaper we give detailed descriptions of its authentic and concurrent evaluation approach by illustrating the what, why and how...... of all evaluation activities throughout the whole project. The project produced seven different design artifacts that were evaluated. The utility and theoretical outcomes of the evaluation activities clearly influenced design decisions regarding newspaper design, user value and business model design...... as well as decisions on strategic levels. We emphasize a holistic and concurrent approach to evaluation compared to the general design science research thinking and argue that reflecting on how to seek authenticity is important. By authenticity we refer to the notion of how closely an evaluation captures...

  8. On Poisson Nonlinear Transformations

    Directory of Open Access Journals (Sweden)

    Nasir Ganikhodjaev

    2014-01-01

    Full Text Available We construct the family of Poisson nonlinear transformations defined on the countable sample space of nonnegative integers and investigate their trajectory behavior. We have proved that these nonlinear transformations are regular.

  9. Micro-transactions for concurrent data structures

    DEFF Research Database (Denmark)

    Meawad, Fadi; Iyer, Karthik; Schoeberl, Martin

    2013-01-01

    implementation of transactional memory that we call micro-transactions. In particular, we argue that hardware support for micro-transactions allows us to efficiently implement certain data structures. Those data structures are difficult to realize with the atomic operations provided by stock hardware and provide......, atomic instructions, and micro-transactions. Our results suggest that transactional memory is an interesting alternative to traditional concurrency control mechanisms....

  10. Continuous Activity Monitoring During Concurrent Chemoradiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Ohri, Nitin, E-mail: ohri.nitin@gmail.com [Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (United States); Kabarriti, Rafi; Bodner, William R.; Mehta, Keyur J. [Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (United States); Shankar, Viswanathan [Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York (United States); Halmos, Balazs; Haigentz, Missak [Department of Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (United States); Rapkin, Bruce [Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York (United States); Guha, Chandan; Kalnicki, Shalom; Garg, Madhur [Department of Radiation Oncology, Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, New York (United States)

    2017-04-01

    Purpose: To perform a prospective trial testing the feasibility and utility of acquiring activity data as a measure of health status during concurrent chemoradiotherapy. Methods and Materials: Ambulatory patients who were planned for treatment with concurrent chemoradiotherapy with curative intent for cancers of the head and neck, lung, or gastrointestinal tract were provided with activity monitors before treatment initiation. Patients were asked to wear the devices continuously throughout the radiation therapy course. Step count data were downloaded weekly during radiation therapy and 2 and 4 weeks after radiation therapy completion. The primary objective was to demonstrate feasibility, defined as collection of step counts for 80% of the days during study subjects' radiation therapy courses. Secondary objectives included establishing step count as a dynamic predictor of unplanned hospitalization risk. Results: Thirty-eight enrolled patients were treated with concurrent chemoradiotherapy. Primary diagnoses included head and neck cancer (n=11), lung cancer (n=13), and a variety of gastrointestinal cancers (n=14). Step data were collected for 1524 of 1613 days (94%) during patients' radiation therapy courses. Fourteen patients were hospitalized during radiation therapy or within 4 weeks of radiation therapy completion. Cox regression modeling demonstrated a significant association between recent step counts (3-day average) and hospitalization risk, with a 38% reduction in the risk of hospitalization for every 1000 steps taken each day (hazard ratio 0.62, 95% confidence interval 0.46-0.83, P=.002). Inferior quality of life scores and impaired performance status were not associated with increased hospitalization risk. Conclusion: Continuous activity monitoring during concurrent chemoradiotherapy is feasible and well-tolerated. Step counts may serve as powerful, objective, and dynamic indicators of hospitalization risk.

  11. Using Molecular Biology to Maximize Concurrent Training

    OpenAIRE

    Baar, Keith

    2014-01-01

    Very few sports use only endurance or strength. Outside of running long distances on a flat surface and power-lifting, practically all sports require some combination of endurance and strength. Endurance and strength can be developed simultaneously to some degree. However, the development of a high level of endurance seems to prohibit the development or maintenance of muscle mass and strength. This interaction between endurance and strength is called the concurrent training effect. This revie...

  12. Continuous Activity Monitoring During Concurrent Chemoradiotherapy

    International Nuclear Information System (INIS)

    Ohri, Nitin; Kabarriti, Rafi; Bodner, William R.; Mehta, Keyur J.; Shankar, Viswanathan; Halmos, Balazs; Haigentz, Missak; Rapkin, Bruce; Guha, Chandan; Kalnicki, Shalom; Garg, Madhur

    2017-01-01

    Purpose: To perform a prospective trial testing the feasibility and utility of acquiring activity data as a measure of health status during concurrent chemoradiotherapy. Methods and Materials: Ambulatory patients who were planned for treatment with concurrent chemoradiotherapy with curative intent for cancers of the head and neck, lung, or gastrointestinal tract were provided with activity monitors before treatment initiation. Patients were asked to wear the devices continuously throughout the radiation therapy course. Step count data were downloaded weekly during radiation therapy and 2 and 4 weeks after radiation therapy completion. The primary objective was to demonstrate feasibility, defined as collection of step counts for 80% of the days during study subjects' radiation therapy courses. Secondary objectives included establishing step count as a dynamic predictor of unplanned hospitalization risk. Results: Thirty-eight enrolled patients were treated with concurrent chemoradiotherapy. Primary diagnoses included head and neck cancer (n=11), lung cancer (n=13), and a variety of gastrointestinal cancers (n=14). Step data were collected for 1524 of 1613 days (94%) during patients' radiation therapy courses. Fourteen patients were hospitalized during radiation therapy or within 4 weeks of radiation therapy completion. Cox regression modeling demonstrated a significant association between recent step counts (3-day average) and hospitalization risk, with a 38% reduction in the risk of hospitalization for every 1000 steps taken each day (hazard ratio 0.62, 95% confidence interval 0.46-0.83, P=.002). Inferior quality of life scores and impaired performance status were not associated with increased hospitalization risk. Conclusion: Continuous activity monitoring during concurrent chemoradiotherapy is feasible and well-tolerated. Step counts may serve as powerful, objective, and dynamic indicators of hospitalization risk.

  13. Concurrent semantics for structured design methods

    OpenAIRE

    Nixon, Patrick

    1996-01-01

    Also in Jelly, I., Gordon, I., & Groll, P. Software Engineering for Parallel and Distributed Systems. London: Chapman Hall. Design methods can be ambiguous due to di#11;erent interpretations of symbols or concepts. This paper presents a formal semantics for the Ward/Mellor Structured Analysis Method for Real Time systems. These semantics ensures that an unambiguous meaning can be attributed to a particular design. Speci#12;cally, it ensures that concurrent and real-time propert...

  14. Salivary gland function after concurrent chemoradiotherapy

    International Nuclear Information System (INIS)

    Ikeda, Kenichiro; Shimane, Toshikazu; Uzuki, Aya; Sugimoto, Akane; Mori, Tomoaki; Akiyama, Rio; Gomibuchi, Hiroshi; Kobayashi, Sei; Sanbe, Takeyuki

    2011-01-01

    Concurrent chemoradiotherapy for cancer of head and neck is becoming more and more prevalent. In fact, it is considered to better maintain quality of life (QOL) of patients than operative treatment in terms of preserving the functions, organs, and structures, but recently I seems that it does not maintain the QOL of patients better than operative treatment because its complications after therapy disturb daily life. We previously conducted a questionnaire survey that investigated the complications experienced by patients who received concurrent chemoradiotherapy, and reported that xerostomia was markedly reduced QOL in these patients. In this study, we divided patients who were exposed to radiation in both major salivary glands into two groups: 20 patients who received a 36 Gy dose of radiation (36 Gy group) and 15 patients who underwent radiation therapy alone at a dose of 40 Gy (radiotherapy (RT) group). The gum test was conducted with the following results (mean volume of saliva): 11.2 ml in the 36 Gy group, 6.0 ml in the RT group. There was no significant difference between the 36 Gy group and RT group. Our findings suggest that there is no significant difference in the extent of salivary gland dysfunction even after chemotherapy is carried out concurrently with radiotherapy. (author)

  15. Paclitaxel and concurrent radiation for gastric cancer

    International Nuclear Information System (INIS)

    Safran, Howard; Wanebo, Harry J.; Hesketh, Paul J.; Akerman, Paul; Ianitti, David; Cioffi, William; Di Petrillo, Thomas; Wolf, Brian; Koness, James; McAnaw, Robert; Moore, Todd; Chen, M.-H.; Radie-Keane, Kathy

    2000-01-01

    Purpose: To determine the activity and toxicity of paclitaxel and concurrent radiation for gastric cancer. Methods and Materials: Twenty-seven patients were studied. Twenty-five had proximal gastric cancers, two had distal cancers. Eight had esophageal extension, 6 had celiac adenopathy, and 7 had retroperitoneal adenopathy. Patients received paclitaxel, 50 mg/m 2 by 3-hour intravenous (IV) infusion, weekly, on days 1, 8, 15, 22, and 29. Radiation was administered concurrently to a total dose of 45.0 Gy, in 1.80 Gy fractions, for 25 treatments. Patients who were medically or surgically inoperable received a sixth week of paclitaxel with a radiation boost to 50.4 Gy. Results: Esophagitis and gastritis were the most important toxicities, Grade 3 in four patients (15%), and Grade 4 in three patients (11%). Five patients (19%) had Grade 3 nausea. The overall response rate was 56%, including three patients (11%) with a complete response. The 2-year progression-free and overall survival rates were 29% and 31%, respectively. Conclusion: Concurrent paclitaxel and radiation demonstrates substantial local-regional activity in gastric cancer. Future investigations combining paclitaxel and radiation with other local-regional and systemic treatments are warranted

  16. Managing Asynchronous Data in ATLAS's Concurrent Framework

    CERN Document Server

    Baines, John; The ATLAS collaboration

    2016-01-01

    In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

  17. Concurrent chemoradiotherapy for advanced esophageal cancer

    International Nuclear Information System (INIS)

    Shimizu, Wakako; Ogino, Takashi; Ishikura, Satoshi; Kawashima, Mitsuhiko; Ikeda, Hiroshi

    1997-01-01

    To investigate factors influencing response and survival for patients with squamous cell cancer of the esophagus. Forty-nine patients with squamous cell cancer of the esophagus, classified by guidelines for the clinical and pathologic studies on carcinoma of the esophagus published by the Japanese Society for Esophageal Disease, were treated by concurrent chemoradiotherapy using chemotherapy consisting of cisplatin and 5-fluorouracil with definitive irradiation of 60 Gy concurrently. Endoscopic findings and biopsy were used for evaluating the response. Nurse charts recording patient's feeding status were adopted to estimate severity of dysphagia. Complete response (CR) rate was 69.4%, median survival time (MST) was 12.3 months, and median local failure-free survival time 7.3 months. Patients in early stage (= 32.4 months, 20.4 months, 20.4 months, 15.7 months, respectively). Patients in A3 stage were often suffered from severe dysphagia both before and after treatment (81.5%, 70.4%), respectively. Concurrent chemoradiotherapy was effective treatment for esophageal cancer. Degree of dysphagia was considered to be a good prognosticator of patients' survival. (author)

  18. Advances in nonlinear optics

    CERN Document Server

    Chen, Xianfeng; Zeng, Heping; Guo, Qi; She, Weilong

    2015-01-01

    This book presents an overview of the state of the art of nonlinear optics from weak light nonlinear optics, ultrafast nonlinear optics to electro-optical theory and applications. Topics range from the fundamental studies of the interaction between matter and radiation to the development of devices, components, and systems of tremendous commercial interest for widespread applications in optical telecommunications, medicine, and biotechnology.

  19. Reliability and Concurrent Validity of the International Personality ...

    African Journals Online (AJOL)

    Reliability and Concurrent Validity of the International Personality item Pool (IPIP) Big-five Factor Markers in Nigeria. ... Nigerian Journal of Psychiatry ... Aims: The aim of this study was to assess the internal consistency and concurrent validity ...

  20. Preliminary Proceedings 15th International Workshop on Expressiveness in Concurrency

    DEFF Research Database (Denmark)

    The EXPRESS workshops aim at bringing together researchers interested in the relations between various formal systems, particularly in the field of Concurrency. More specifically, they focus on the comparison between programming concepts (such as concurrent, functional, imperative, logic and obje...

  1. Enhancing Thermoelectric Performance Using Nonlinear Transport Effects

    Science.gov (United States)

    Jiang, Jian-Hua; Imry, Yoseph

    2017-06-01

    We study nonlinear transport effects on the maximum efficiency and power for both inelastic and elastic thermoelectric generators. The former device refers to phonon-assisted hopping in double quantum dots, while the latter device is represented by elastic tunneling through a single quantum dot. We find that nonlinear thermoelectric transport can lead to enhanced efficiency and power for both types of devices. A comprehensive survey of various quantum-dot energy, temperature, and parasitic heat conduction reveals that the nonlinear transport-induced improvements of the maximum efficiency and power are overall much more significant for inelastic devices than for elastic devices, even for temperature biases as small as Th=1.2 Tc (Th and Tc are the temperatures of the hot and cold reservoirs, respectively). The underlying mechanism is revealed as due to the fact that, unlike the Fermi distribution, the Bose distribution is not bounded when the temperature bias increases. A large flux density of absorbed phonons leads to a great enhancement of the electrical current, output power, and energy efficiency, dominating over the concurrent increase of the parasitic heat current. Our study reveals that nonlinear transport effects can be a useful tool for improving thermoelectric performance.

  2. Quantum Nonlinear Optics

    CERN Document Server

    Hanamura, Eiichi; Yamanaka, Akio

    2007-01-01

    This graduate-level textbook gives an introductory overview of the fundamentals of quantum nonlinear optics. Based on the quantum theory of radiation, Quantum Nonlinear Optics incorporates the exciting developments in novel nonlinear responses of materials (plus laser oscillation and superradiance) developed over the past decade. It deals with the organization of radiation field, interaction between electronic system and radiation field, statistics of light, mutual manipulation of light and matter, laser oscillation, dynamics of light, nonlinear optical response, and nonlinear spectroscopy, as well as ultrashort and ultrastrong laser pulse. Also considered are Q-switching, mode locking and pulse compression. Experimental and theoretical aspects are intertwined throughout.

  3. Nonlinear dynamics and complexity

    CERN Document Server

    Luo, Albert; Fu, Xilin

    2014-01-01

    This important collection presents recent advances in nonlinear dynamics including analytical solutions, chaos in Hamiltonian systems, time-delay, uncertainty, and bio-network dynamics. Nonlinear Dynamics and Complexity equips readers to appreciate this increasingly main-stream approach to understanding complex phenomena in nonlinear systems as they are examined in a broad array of disciplines. The book facilitates a better understanding of the mechanisms and phenomena in nonlinear dynamics and develops the corresponding mathematical theory to apply nonlinear design to practical engineering.

  4. Distributed nonlinear optical response

    DEFF Research Database (Denmark)

    Nikolov, Nikola Ivanov

    2005-01-01

    of bound states of out of phase bright solitons and dark solitons. Also, the newly introduced analogy between the nonlocal cubic nonlinear and the quadratic nonlinear media, presented in paper B and Chapter 3 is discussed. In particular it supplies intuitive physical meaning of the formation of solitons...... in quadratic nonlinear media. In the second part of the report (Chapter 4), the possibility to obtain light with ultrabroad spectrum due to the interplay of many nonlinear effects based on cubic nonlinearity is investigated thoroughly. The contribution of stimulated Raman scattering, a delayed nonlinear...... a modified nonlinear Schroedinger model equation. Chapter 4 and papers D and E are dedicated to this part of the research....

  5. Concurrent paclitaxel and radiotherapy. Treatment feasibility studies

    International Nuclear Information System (INIS)

    Vogt, H.G.; Martin, T.; Kolotas, C.; Hey, S.; Schneider, L.; Templin, T.; Zamboglou, N.; Dornoff, W.; Kettner, H.

    1997-01-01

    Background: The anti-neoplastic effect of paclitaxel has been demonstrated in various clinical studies in different malignant diseases. Clinical studies have also demonstrated a greater efficacy for simultaneous radio-chemotherapy compared with radiotherapy alone when using radiosensitizing drugs. Based on these clinical and in-vitro data we initiated several pilot studies using paclitaxel as a radiosensitizing agent and we now present our initial experience in its use in a combined modality protocol, radiation and simultaneous chemotherapy with paclitaxel. Methods: I. Concurrent paclitaxel and radiation for locally advanced non-small-cell lung cancer (NSCLC): In a phase-I-study we applicated paclitaxel (45 to 65 mg/m 2 ) as a 3-hour infusion weekly for 3 to 7 weeks simultaneously with primary radiotherapy in shrinking field technique with 5x1.8 Gy/week up to 59.4 Gy. - II. Concurrent paclitaxel and radiation for breast cancer as neoadjuvant or palliative: 50 mg/m 2 paclitaxel as a 3-hour infusion weekly for 6 weeks simultaneous with neoadjuvant or palliative radiotherapy of the breast/chest wall with 5x1.8 Gy/week up to 54.0 Gy. - III./IV. Concurrent paclitaxel/carboplatin and combined radiation (EBRT+brachytherapy) for locally advanced inoperable cancer of the cervix: 50 mg/m 2 paclitaxel as a 3-hour infusion weekly for 5 weeks, 50 mg/m 2 carboplatin at day 1 to 5 in week 1 and 5 simultaneously with external beam radiotherapy of the pelvis with 5x1.8 Gy/week up to 54.0 Gy and endocavitary LDR-brachytherapy (4x5 Gy). - V. Concurrent paclitaxel and radiation for locally advanced inoperable cancer of the bladder: 50 mg/m 2 paclitaxel as a 3-hour infusion weekly for 5 weeks simultaneous with radiotherapy of the pelvis with 5x1.8 Gy/week up to 50.4 Gy. VI. Concurrent paclitaxel and radiation in locally advanced inoperable head and neck cancer: 50 mg/m 2 paclitaxel as a 3-hour infusion weekly for 7 to 8 weeks simultaneous with radiotherapy in shrinking field technique

  6. Concurrent conditional clustering of multiple networks: COCONETS.

    Directory of Open Access Journals (Sweden)

    Sabrina Kleessen

    Full Text Available The accumulation of high-throughput data from different experiments has facilitated the extraction of condition-specific networks over the same set of biological entities. Comparing and contrasting of such multiple biological networks is in the center of differential network biology, aiming at determining general and condition-specific responses captured in the network structure (i.e., included associations between the network components. We provide a novel way for comparison of multiple networks based on determining network clustering (i.e., partition into communities which is optimal across the set of networks with respect to a given cluster quality measure. To this end, we formulate the optimization-based problem of concurrent conditional clustering of multiple networks, termed COCONETS, based on the modularity. The solution to this problem is a clustering which depends on all considered networks and pinpoints their preserved substructures. We present theoretical results for special classes of networks to demonstrate the implications of conditionality captured by the COCONETS formulation. As the problem can be shown to be intractable, we extend an existing efficient greedy heuristic and applied it to determine concurrent conditional clusters on coexpression networks extracted from publically available time-resolved transcriptomics data of Escherichia coli under five stresses as well as on metabolite correlation networks from metabolomics data set from Arabidopsis thaliana exposed to eight environmental conditions. We demonstrate that the investigation of the differences between the clustering based on all networks with that obtained from a subset of networks can be used to quantify the specificity of biological responses. While a comparison of the Escherichia coli coexpression networks based on seminal properties does not pinpoint biologically relevant differences, the common network substructures extracted by COCONETS are supported by

  7. Relaxed Operational Semantics of Concurrent Programming Languages

    Directory of Open Access Journals (Sweden)

    Gustavo Petri

    2012-08-01

    Full Text Available We propose a novel, operational framework to formally describe the semantics of concurrent programs running within the context of a relaxed memory model. Our framework features a "temporary store" where the memory operations issued by the threads are recorded, in program order. A memory model then specifies the conditions under which a pending operation from this sequence is allowed to be globally performed, possibly out of order. The memory model also involves a "write grain," accounting for architectures where a thread may read a write that is not yet globally visible. Our formal model is supported by a software simulator, allowing us to run litmus tests in our semantics.

  8. Moments analysis of concurrent Poisson processes

    International Nuclear Information System (INIS)

    McBeth, G.W.; Cross, P.

    1975-01-01

    A moments analysis of concurrent Poisson processes has been carried out. Equations are given which relate combinations of distribution moments to sums of products involving the number of counts associated with the processes and the mean rate of the processes. Elimination of background is discussed and equations suitable for processing random radiation, parent-daughter pairs in the presence of background, and triple and double correlations in the presence of background are given. The theory of identification of the four principle radioactive series by moments analysis is discussed. (Auth.)

  9. Amplitude modulation detection with concurrent frequency modulation.

    Science.gov (United States)

    Nagaraj, Naveen K

    2016-09-01

    Human speech consists of concomitant temporal modulations in amplitude and frequency that are crucial for speech perception. In this study, amplitude modulation (AM) detection thresholds were measured for 550 and 5000 Hz carriers with and without concurrent frequency modulation (FM), at AM rates crucial for speech perception. Results indicate that adding 40 Hz FM interferes with AM detection, more so for 5000 Hz carrier and for frequency deviations exceeding the critical bandwidth of the carrier frequency. These findings suggest that future cochlear implant processors, encoding speech fine-structures may consider limiting the FM to narrow bandwidth and to low frequencies.

  10. Concurrency control in distributed database systems

    CERN Document Server

    Cellary, W; Gelenbe, E

    1989-01-01

    Distributed Database Systems (DDBS) may be defined as integrated database systems composed of autonomous local databases, geographically distributed and interconnected by a computer network.The purpose of this monograph is to present DDBS concurrency control algorithms and their related performance issues. The most recent results have been taken into consideration. A detailed analysis and selection of these results has been made so as to include those which will promote applications and progress in the field. The application of the methods and algorithms presented is not limited to DDBSs but a

  11. Who would benefit from memory training? A pilot study examining the ceiling effect of concurrent cognitive stimulation

    Directory of Open Access Journals (Sweden)

    Kwok TCY

    2011-03-01

    Full Text Available Timothy CY Kwok1,2, Wai Wang Chau1, Kenneth SL Yuen1,3, Anita YM Wong4, Jessie CY Li1, Rebecca YY Shiu4, Florence KY Ho11Jockey Club Centre for Positive Ageing, Hong Kong; 2Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong; 3Laboratory of Neuropsychology, Department of Psychology, University of Hong Kong, Pokfulam, Hong Kong; 4The Hong Kong Chinese Women's Club Madam Wong Chan Sook Ying Memorial Care and Attention Home for the Aged, Hong KongAbstract: Diverse effects of memory training were observed in the literature. One possible factor is the amount of concurrent cognitive training received during the training program. In this pilot study, we recruited 24 elderly adults with or without concurrent cognitive stimulations to attend a memory-training program. Findings suggested that elderly people without concurrent cognitive stimulation could benefit from a memory-training program in the form of improved initiation and memory functioning. Self-rated quality of life measure also showed improvements alongside the cognitive benefits. Elderly people with regular concurrent cognitive stimulation, on the other hand, seemed to plateau in their level of performance and did not show any significant change. Our preliminary findings suggested nonlinear concurrent cognitive stimulation in the elderly.Keywords: memory training, cognitive training, dementia, Chinese, elderly 

  12. A concurrent multiscale micromorphic molecular dynamics

    International Nuclear Information System (INIS)

    Li, Shaofan; Tong, Qi

    2015-01-01

    In this work, we have derived a multiscale micromorphic molecular dynamics (MMMD) from first principle to extend the (Andersen)-Parrinello-Rahman molecular dynamics to mesoscale and continuum scale. The multiscale micromorphic molecular dynamics is a con-current three-scale dynamics that couples a fine scale molecular dynamics, a mesoscale micromorphic dynamics, and a macroscale nonlocal particle dynamics together. By choosing proper statistical closure conditions, we have shown that the original Andersen-Parrinello-Rahman molecular dynamics is the homogeneous and equilibrium case of the proposed multiscale micromorphic molecular dynamics. In specific, we have shown that the Andersen-Parrinello-Rahman molecular dynamics can be rigorously formulated and justified from first principle, and its general inhomogeneous case, i.e., the three scale con-current multiscale micromorphic molecular dynamics can take into account of macroscale continuum mechanics boundary condition without the limitation of atomistic boundary condition or periodic boundary conditions. The discovered multiscale scale structure and the corresponding multiscale dynamics reveal a seamless transition from atomistic scale to continuum scale and the intrinsic coupling mechanism among them based on first principle formulation

  13. Note on specifying and verifying concurrent processes

    Energy Technology Data Exchange (ETDEWEB)

    Holenderski, L.

    1984-02-28

    To represent sequential processes, sets of finite sequences of symbols from a finite alphabet are used in this approach, alphabet symbols denote events occurring when a process is being executed, a sequence of symbols is a record of one execution of the process, and a set of such sequences represents the process itself by combining all its possible executions together. Although this model turned out adequate for specifying concurrent processes and allows proving their properties, there are two reasons, at least, why this note takes the same subject up again. First, by analogy to shuffle and its closure, which express parallel combination and parallel iteration of non-interacting processes, there is a need for a similar operation describing the behaviour of interaction processes. A new extension of shuffle is proposed as a generalization. The closure of this operation provides a tool for specification of parallelly iterated processes. Moreover, the closure makes mutually recursive specification unnecessary. Second, when this model was used to prove properties of concurrent computations, only flow-of-control schemes were considered (thus, only some general properties were proved). When applied to concrete programs using variables that have values, such schemes had to be interpreted. In contrast to such a schematic approach, the usefulness of the same method for concrete programs is argued. This is shown using an example of a correctness proof of an implementation of unbounded semaphore by binary semaphores. 8 references.

  14. Nonlinear Dirac Equations

    Directory of Open Access Journals (Sweden)

    Wei Khim Ng

    2009-02-01

    Full Text Available We construct nonlinear extensions of Dirac's relativistic electron equation that preserve its other desirable properties such as locality, separability, conservation of probability and Poincaré invariance. We determine the constraints that the nonlinear term must obey and classify the resultant non-polynomial nonlinearities in a double expansion in the degree of nonlinearity and number of derivatives. We give explicit examples of such nonlinear equations, studying their discrete symmetries and other properties. Motivated by some previously suggested applications we then consider nonlinear terms that simultaneously violate Lorentz covariance and again study various explicit examples. We contrast our equations and construction procedure with others in the literature and also show that our equations are not gauge equivalent to the linear Dirac equation. Finally we outline various physical applications for these equations.

  15. Nonlinear graphene plasmonics

    Science.gov (United States)

    Ooi, Kelvin J. A.; Tan, Dawn T. H.

    2017-10-01

    The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique two-dimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications.

  16. Silicon Photonics: All-Optical Devices for Linear and Nonlinear Applications

    Science.gov (United States)

    Driscoll, Jeffrey B.

    are shown to contribute no time-averaged momentum. Furthermore, the vectoral modal components, in conjunction with the tensoral nature of the third-order susceptibility of Si, lead to nonlinear properties which are dependent on waveguide orientation with respect to the Si parent crystal and the construction of the modal electric field components. This consideration is used to maximize effective nonlinearity and realize nonlinear Kerr gratings along specific waveguide trajectories. Tight optical confinement leads to a natural enhancement of the intrinsically large effective nonlinearty of Si waveguides, and in fact, the effective nonlinearty can be made to be almost 106 times greater in Si waveguides than that of standard single-mode fiber. Such a large nonlinearity motivates chip-scale all-optical signal processing techniques. Wavelength conversion by both four-wave-mixing (FWM) and cross-phase-modulation (XPM) will be discussed, including a technique that allows for enhanced broadband discrete FWM over arbitrary spectral spans by modulating both the linear and nonlinear waveguide properties through periodic changes in waveguide geometry. This quasi-phase-matching approach has very real applications towards connecting mature telecom sources detectors and components to other spectral regimes, including the mid-IR. Other signal processing techniques such as all-optical modulation format conversion via XPM will also be discussed. This thesis will conclude by looking at ways to extend the bandwidth capacity of Si waveguide interconnects on chip. As the number of processing cores continues to scale as a means for computational performance gains, on-chip link capacity will become an increasingly important issue. Metallic traces have severe limitations and are envisioned to eventually bow to integrated photonic links. The aggregate bandwidth supported by a single waveguide link will therefore become a crucial consideration as integrated photonics approaches the CPU. One way

  17. Concurrent Engineering Working Group White Paper Distributed Collaborative Design: The Next Step in Aerospace Concurrent Engineering

    Science.gov (United States)

    Hihn, Jairus; Chattopadhyay, Debarati; Karpati, Gabriel; McGuire, Melissa; Panek, John; Warfield, Keith; Borden, Chester

    2011-01-01

    As aerospace missions grow larger and more technically complex in the face of ever tighter budgets, it will become increasingly important to use concurrent engineering methods in the development of early conceptual designs because of their ability to facilitate rapid assessments and trades of performance, cost and schedule. To successfully accomplish these complex missions with limited funding, it is essential to effectively leverage the strengths of individuals and teams across government, industry, academia, and international agencies by increased cooperation between organizations. As a result, the existing concurrent engineering teams will need to increasingly engage in distributed collaborative concurrent design. The purpose of this white paper is to identify a near-term vision for the future of distributed collaborative concurrent engineering design for aerospace missions as well as discuss the challenges to achieving that vision. The white paper also documents the advantages of creating a working group to investigate how to engage the expertise of different teams in joint design sessions while enabling organizations to maintain their organizations competitive advantage.

  18. Stationary nonlinear Airy beams

    International Nuclear Information System (INIS)

    Lotti, A.; Faccio, D.; Couairon, A.; Papazoglou, D. G.; Panagiotopoulos, P.; Tzortzakis, S.; Abdollahpour, D.

    2011-01-01

    We demonstrate the existence of an additional class of stationary accelerating Airy wave forms that exist in the presence of third-order (Kerr) nonlinearity and nonlinear losses. Numerical simulations and experiments, in agreement with the analytical model, highlight how these stationary solutions sustain the nonlinear evolution of Airy beams. The generic nature of the Airy solution allows extension of these results to other settings, and a variety of applications are suggested.

  19. Generalized Nonlinear Yule Models

    OpenAIRE

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-01-01

    With the aim of considering models with persistent memory we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macrovolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth...

  20. Nonlinear evolution equations

    CERN Document Server

    Uraltseva, N N

    1995-01-01

    This collection focuses on nonlinear problems in partial differential equations. Most of the papers are based on lectures presented at the seminar on partial differential equations and mathematical physics at St. Petersburg University. Among the topics explored are the existence and properties of solutions of various classes of nonlinear evolution equations, nonlinear imbedding theorems, bifurcations of solutions, and equations of mathematical physics (Navier-Stokes type equations and the nonlinear Schrödinger equation). The book will be useful to researchers and graduate students working in p

  1. Nonlinear Physics of Plasmas

    CERN Document Server

    Kono, Mitsuo

    2010-01-01

    A nonlinearity is one of the most important notions in modern physics. A plasma is rich in nonlinearities and provides a variety of behaviors inherent to instabilities, coherent wave structures and turbulence. The book covers the basic concepts and mathematical methods, necessary to comprehend nonlinear problems widely encountered in contemporary plasmas, but also in other fields of physics and current research on self-organized structures and magnetized plasma turbulence. The analyses make use of strongly nonlinear models solved by analytical techniques backed by extensive simulations and available experiments. The text is written for senior undergraduates, graduate students, lecturers and researchers in laboratory, space and fusion plasmas.

  2. Nonlinear optics at interfaces

    International Nuclear Information System (INIS)

    Chen, C.K.

    1980-12-01

    Two aspects of surface nonlinear optics are explored in this thesis. The first part is a theoretical and experimental study of nonlinear intraction of surface plasmons and bulk photons at metal-dielectric interfaces. The second part is a demonstration and study of surface enhanced second harmonic generation at rough metal surfaces. A general formulation for nonlinear interaction of surface plasmons at metal-dielectric interfaces is presented and applied to both second and third order nonlinear processes. Experimental results for coherent second and third harmonic generation by surface plasmons and surface coherent antiStokes Raman spectroscopy (CARS) are shown to be in good agreement with the theory

  3. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  4. Concurrent radiochemotherapy in advanced hypopharyngeal cancer

    Directory of Open Access Journals (Sweden)

    Lukarski Dusko

    2010-05-01

    Full Text Available Abstract Background Concurrent platinum-based radiochemotherapy has been recommended as a standard of care in patients with locally advanced squamous cell head and neck carcinomas. Unfortunately, there is a lack of level one evidence on best treatment approach for advanced hypopharyngeal cancer. This report aims to summarize the results of our study on concurrent radiochemotherapy in patients with advanced hypopharyngeal cancer. Methods A retrospective analysis of 41 patients with stage III-IV hypopharyngeal cancer was performed. All patients were treated with three dimensional conformal radiotherapy and received 70 Gy in 35 fractions (2 Gy per fraction, 5 fractions per week. In dependence of the period when radiotherapy was realized, two different treatment techniques were used. Concurrent chemotherapy consisted of cisplatin 30 mg/m2 given on a weekly basis. Results The median age was 52 years (range 29-70. Stage IV disease was recognized in 73.2% of the patients. Complete response rates at the primary site and at the metastatic neck lymph nodes were 68.3% and 36.6%, respectively. A complete composite response was present in 27 patients (65.9%. Median follow-up was 13 months (range 7-36. Distant metastases as initial failure occurred in 7 patients (46.7%. The 2-year local relapse-free survival and regional relapse-free survival rates were 55.2% and 75.8%, respectively. The 2-year locoregional relapse-free survival rate was 51.3%. The 2-year disease-free survival and overall survival rates were 29.3% and 32.8%, respectively. Confluent mucositis was developed in 46.3% of patients. Leucopenia grade 1 was the most frequent hematological toxicity. The median weight loss at the end of treatment was 12% (range 5-21. The worst grade of late toxicity was most commonly pronounced in the skin and in the subcutaneous tissue. Conclusions Based on unsatisfactory results in our study we suggest that the use of sequential radiochemotherapy or chemotherapy

  5. Concurrent chemoradiation for unresectable pancreatic cancer

    International Nuclear Information System (INIS)

    Kim, Yong Bae; Seong, Jin Sil; Song, Si Young; Park, Seung Woo; Suh, Chang Ok

    2002-01-01

    To analyze the treatment results of concurrent chemoradiation with oral 5-FU plus Gemcitabine or Paclitaxel for unresectable pancreatic cancer. The patients, who were diagnosed by imaging modalities or by explo-laparotomy were treated with concurrent chemoradiation. Radiotherapy was delivered to primary tumor and regional lymph nodes, and the total dose was 45 Gy. Patients received Gemcitabine 1,000 mg/m 2 or Paclitaxel 50 mg/m 2 weekly and oral 5-FU daily. The total number of cycles of chemotherapy ranged from 1 to 39 (median, 11 cycles). The follow-up period ranged from 6 to 36 months. Survival was analyzed using the Kaplan-Meier method. Fifty-four patients between Jan. 1999 to Nov. 2001 were included in this study. Forty-two patients who completed the planned treatment were included in this analysis. The patients' age ranged from 37 to 73 years (median, 60 years) and the male to female ratio was 30:12. Treatment was interrupted for 12 patients due to; disease progression for 6 (50%), poor performance status for 4 (33.3%), intercurrent disease for 1 (8.3%), and refusal for 1 (8.3%). Response evaluation was possible for 40 patients. One patient gained complete remission and 24 patients gained partial remission, hence the response rate was 59%. The survival rates were 46.7% and 17.0% at 1 year and 2 years, respectively with a median survival time of 12 months. Patients treated with Paclitaxel showed superior outcomes compared to those patients treated with Gemcitabine, in terms of both response rate and survival rate although this difference was not statistically significant. Grade III or IV hematologic toxicity was shown in 8 patients (19%), while grade III or IV non-hematologic toxicity was shown in 5 patients (12%). Concurrent chemoradiation with oral 5-FU and Gemcitabine or Paclitaxel improves both the response rate and survival rate in patients with unresectable pancreatic cancer. A prospective study should be investigated in order to improve both the patient

  6. Polarization Nonlinear Optics of Quadratically Nonlinear Azopolymers

    International Nuclear Information System (INIS)

    Konorov, S.O.; Akimov, D.A.; Ivanov, A.A.; Petrov, A.N.; Alfimov, M.V.; Yakimanskii, A.V.; Smirnov, N.N.; Ivanova, V.N.; Kudryavtsev, V.V.; Podshivalov, A.A.; Sokolova, I.M.; Zheltikov, A.M.

    2005-01-01

    The polarization properties of second harmonic and sum-frequency signals generated by femtosecond laser pulses in films of polymers containing covalent groups of an azobenzothiazole chromophore polarized by an external electric field are investigated. It is shown that the methods of polarization nonlinear optics make it possible to determine the structure of oriented molecular dipoles and reveal important properties of the motion of collectivized πelectrons in organic molecules with strong optical nonlinearities. The polarization measurements show that the tensor of quadratic nonlinear optical susceptibility of chromophore fragments oriented by an external field in macromolecules of the noted azopolymers has a degenerate form. This is indicative of a predominantly one-dimensional character of motion of collectivized π electrons along an extended group of atoms in such molecules

  7. Distributed Management of Concurrent Web Service Transactions

    DEFF Research Database (Denmark)

    Alrifai, Mohammad; Dolog, Peter; Balke, Wolf-Tilo

    2009-01-01

    Business processes involve dynamic compositions of interleaved tasks. Therefore, ensuring reliable transactional processing of Web services is crucial for the success of Web service-based B2B and B2C applications. But the inherent autonomy and heterogeneity of Web services render the applicability...... of conventional ACID transaction models for Web services far from being straightforward. Current Web service transaction models relax the isolation property and rely on compensation mechanisms to ensure atomicity of business transactions in the presence of service failures. However, ensuring consistency...... in the open and dynamic environment of Web services, where interleaving business transactions enter and exit the system independently, remains an open issue. In this paper, we address this problem and propose an architecture that supports concurrency control on the Web services level. An extension...

  8. Concurrent hypokalemic periodic paralysis and bipolar disorder

    Directory of Open Access Journals (Sweden)

    Chia-Lin Lin

    2015-01-01

    Full Text Available Primary periodic paralysis is a rare autosomal dominant disorder of ion-channel dysfunction, manifested by episodic flaccid paresis secondary to abnormal sarcolemma excitability. Membrane destabilization involving Na, K-ATPase has been hypothesized to be a biological etiology of the bipolar disorder (BD and the mechanisms underlying lithium therapy have been linked to it. To date, there has been only one reported case of BD comorbid with periodic paralysis. Herein, we reported another case of concurrent bipolar mania and hypokalemic periodic paralysis (HPP, one special form of periodic paralysis. Consistent with the previous case, our patient responded well to lithium treatment for both bipolar mania and HPP. This might provide some support to the hypothesis that the therapeutic effects of lithium in both BD and HPP could be due to the correction of the underlying common pathophysiology.

  9. High bandwidth concurrent processing on commodity platforms

    CERN Document Server

    Boosten, M; Van der Stok, P D V

    1999-01-01

    The I/O bandwidth and real-time processing power required for high- energy physics experiments is increasing rapidly over time. The current requirements can only be met by using large-scale concurrent processing. We are investigating the use of a large PC cluster interconnected by Fast and Gigabit Ethernet to meet the performance requirements of the ATLAS second level trigger. This architecture is attractive because of its performance and competitive pricing. A major problem is obtaining frequent high-bandwidth I/O without sacrificing the CPU's processing power. We present a tight integration of a user-level scheduler and a zero-copy communication layer. This system closely approaches the performance of the underlying hardware in terms of both CPU power and I/O capacity. (0 refs).

  10. Nonlinear dynamics in Nuclotron

    International Nuclear Information System (INIS)

    Dinev, D.

    1997-01-01

    The paper represents an extensive study of the nonlinear beam dynamics in the Nuclotron. Chromatic effects, including the dependence of the betatron tunes on the amplitude, and chromatic perturbations have been investigated taking into account the measured field imperfections. Beam distortion, smear, dynamic aperture and nonlinear acceptance have been calculated for different particle energies and betatron tunes

  11. Nonlinear Optics and Applications

    Science.gov (United States)

    Abdeldayem, Hossin A. (Editor); Frazier, Donald O. (Editor)

    2007-01-01

    Nonlinear optics is the result of laser beam interaction with materials and started with the advent of lasers in the early 1960s. The field is growing daily and plays a major role in emerging photonic technology. Nonlinear optics play a major role in many of the optical applications such as optical signal processing, optical computers, ultrafast switches, ultra-short pulsed lasers, sensors, laser amplifiers, and many others. This special review volume on Nonlinear Optics and Applications is intended for those who want to be aware of the most recent technology. This book presents a survey of the recent advances of nonlinear optical applications. Emphasis will be on novel devices and materials, switching technology, optical computing, and important experimental results. Recent developments in topics which are of historical interest to researchers, and in the same time of potential use in the fields of all-optical communication and computing technologies, are also included. Additionally, a few new related topics which might provoke discussion are presented. The book includes chapters on nonlinear optics and applications; the nonlinear Schrodinger and associated equations that model spatio-temporal propagation; the supercontinuum light source; wideband ultrashort pulse fiber laser sources; lattice fabrication as well as their linear and nonlinear light guiding properties; the second-order EO effect (Pockels), the third-order (Kerr) and thermo-optical effects in optical waveguides and their applications in optical communication; and, the effect of magnetic field and its role in nonlinear optics, among other chapters.

  12. Erlang Programming A Concurrent Approach to Software Development

    CERN Document Server

    Cesarini, Francesco

    2009-01-01

    This book offers you an in-depth explanation of Erlang, a programming language ideal for any situation where concurrency, fault-tolerance, and fast response is essential. You'll learn how to write complex concurrent programs in this language, regardless of your programming background or experience. Erlang Programming focuses on the language's syntax and semantics, and explains pattern matching, proper lists, recursion, debugging, networking, and concurrency, with exercises at the end of each chapter.

  13. Nonlinear optical systems

    CERN Document Server

    Lugiato, Luigi; Brambilla, Massimo

    2015-01-01

    Guiding graduate students and researchers through the complex world of laser physics and nonlinear optics, this book provides an in-depth exploration of the dynamics of lasers and other relevant optical systems, under the umbrella of a unitary spatio-temporal vision. Adopting a balanced approach, the book covers traditional as well as special topics in laser physics, quantum electronics and nonlinear optics, treating them from the viewpoint of nonlinear dynamical systems. These include laser emission, frequency generation, solitons, optically bistable systems, pulsations and chaos and optical pattern formation. It also provides a coherent and up-to-date treatment of the hierarchy of nonlinear optical models and of the rich variety of phenomena they describe, helping readers to understand the limits of validity of each model and the connections among the phenomena. It is ideal for graduate students and researchers in nonlinear optics, quantum electronics, laser physics and photonics.

  14. A Highly Concurrent Replicated Data Structure EAI Endorsed Transactions

    Directory of Open Access Journals (Sweden)

    Mumtaz Ahmad

    2015-12-01

    Full Text Available Well defined concurrent replicated data structure is very important to design collaborative editing system, particularly, certain properties like out-of-order execution of concurrent operations and data convergence. In this paper, we introduce novel linear data structure based on unique identifier scheme required for indexed communication. These identifiers are real numbers holding specific pattern of precision. Based on the uniqueness and the total order of these identifiers, here, we present two concurrency control techniques to achieve high degree of concurrency according to strong and lazy happened-before relations. Our data structure preserves data convergence, yields better performance and avoids overheads as compared to existing approaches.

  15. Continuous variable tripartite entanglement and Einstein-Podolsky-Rosen correlations from triple nonlinearities

    International Nuclear Information System (INIS)

    Olsen, M K; Bradley, A S; Reid, M D

    2006-01-01

    We compare theoretically the tripartite entanglement available from the use of three concurrent χ (2) nonlinearities and three independent squeezed states mixed on beamsplitters, using an appropriate version of the van Loock-Furusawa inequalities. We also define three-mode generalizations of the Einstein-Podolsky-Rosen paradox which are an alternative for demonstrating the inseparability of the density matrix

  16. Nonlinear photonic metasurfaces

    Science.gov (United States)

    Li, Guixin; Zhang, Shuang; Zentgraf, Thomas

    2017-03-01

    Compared with conventional optical elements, 2D photonic metasurfaces, consisting of arrays of antennas with subwavelength thickness (the 'meta-atoms'), enable the manipulation of light-matter interactions on more compact platforms. The use of metasurfaces with spatially varying arrangements of meta-atoms that have subwavelength lateral resolution allows control of the polarization, phase and amplitude of light. Many exotic phenomena have been successfully demonstrated in linear optics; however, to meet the growing demand for the integration of more functionalities into a single optoelectronic circuit, the tailorable nonlinear optical properties of metasurfaces will also need to be exploited. In this Review, we discuss the design of nonlinear photonic metasurfaces — in particular, the criteria for choosing the materials and symmetries of the meta-atoms — for the realization of nonlinear optical chirality, nonlinear geometric Berry phase and nonlinear wavefront engineering. Finally, we survey the application of nonlinear photonic metasurfaces in optical switching and modulation, and we conclude with an outlook on their use for terahertz nonlinear optics and quantum information processing.

  17. Nonlinear crack mechanics

    International Nuclear Information System (INIS)

    Khoroshun, L.P.

    1995-01-01

    The characteristic features of the deformation and failure of actual materials in the vicinity of a crack tip are due to their physical nonlinearity in the stress-concentration zone, which is a result of plasticity, microfailure, or a nonlinear dependence of the interatomic forces on the distance. Therefore, adequate models of the failure mechanics must be nonlinear, in principle, although linear failure mechanics is applicable if the zone of nonlinear deformation is small in comparison with the crack length. Models of crack mechanics are based on analytical solutions of the problem of the stress-strain state in the vicinity of the crack. On account of the complexity of the problem, nonlinear models are bason on approximate schematic solutions. In the Leonov-Panasyuk-Dugdale nonlinear model, one of the best known, the actual two-dimensional plastic zone (the nonlinearity zone) is replaced by a narrow one-dimensional zone, which is then modeled by extending the crack with a specified normal load equal to the yield point. The condition of finite stress is applied here, and hence the length of the plastic zone is determined. As a result of this approximation, the displacement in the plastic zone at the abscissa is nonzero

  18. Nonlinear wave equations

    CERN Document Server

    Li, Tatsien

    2017-01-01

    This book focuses on nonlinear wave equations, which are of considerable significance from both physical and theoretical perspectives. It also presents complete results on the lower bound estimates of lifespan (including the global existence), which are established for classical solutions to the Cauchy problem of nonlinear wave equations with small initial data in all possible space dimensions and with all possible integer powers of nonlinear terms. Further, the book proposes the global iteration method, which offers a unified and straightforward approach for treating these kinds of problems. Purely based on the properties of solut ions to the corresponding linear problems, the method simply applies the contraction mapping principle.

  19. Concurrent applicative implementations of nondeterministic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Salter, R

    1983-01-01

    The author introduces a methodology for utilizing concurrency in place of backtracking in the implementation of nondeterministic algorithms. This is achieved in an applicative setting through the use of the Friedman-Wise multiprogramming primitive frons, and a paradigm which views the action of nondeterministic algorithms as one of data structure construction. The element by element nondeterminism arising from a linearized search is replaced by a control structure which is oriented towards constructing sets of partial computations. This point of view is facilitated by the use of suspensions, which allow control disciplines to be embodied in the form of conceptual data structures that in reality manifest themselves only for purposes of control. He applies this methodology to the class of problems usually solved through the use of simple backtracking (e.g. 'eight queens'), and to a problem presented by Lindstrom (1979) to illustrate the use of coroutine controlled backtracking, to produce backtrack-free solutions. The solution to the latter illustrates the coroutine capability of suspended structures, but also demonstrates a need for further investigations into resolving problems of process communication in applicative languages. 14 references.

  20. Creatine and Caffeine: Considerations for Concurrent Supplementation.

    Science.gov (United States)

    Trexler, Eric T; Smith-Ryan, Abbie E

    2015-12-01

    Nutritional supplementation is a common practice among athletes, with creatine and caffeine among the most commonly used ergogenic aids. Hundreds of studies have investigated the ergogenic potential of creatine supplementation, with consistent improvements in strength and power reported for exercise bouts of short duration (≤ 30 s) and high intensity. Caffeine has been shown to improve endurance exercise performance, but results are mixed in the context of strength and sprint performance. Further, there is conflicting evidence from studies comparing the ergogenic effects of coffee and caffeine anhydrous supplementation. Previous research has identified independent mechanisms by which creatine and caffeine may improve strength and sprint performance, leading to the formulation of multi-ingredient supplements containing both ingredients. Although scarce, research has suggested that caffeine ingestion may blunt the ergogenic effect of creatine. While a pharmacokinetic interaction is unlikely, authors have suggested that this effect may be explained by opposing effects on muscle relaxation time or gastrointestinal side effects from simultaneous consumption. The current review aims to evaluate the ergogenic potential of creatine and caffeine in the context of high-intensity exercise. Research directly comparing coffee and caffeine anhydrous is discussed, along with previous studies evaluating the concurrent supplementation of creatine and caffeine.

  1. Concurrent Oxytocin in Women Needing Second Dinoprostone

    International Nuclear Information System (INIS)

    Sher, Z.; Ashraf, M.; Irum, N.; Bashir, S.; Khaliq, N.; Yaqub, S.

    2015-01-01

    Objective: To reduce average induction delivery internal in patients with poor Bishop score without compromising fetomaternal outcome (in terms of birth weight, NICU admission, maternal complications and mode of delivery). Study Design: A descriptive study. Place and Duration of Study: Department of Obstetrics and Gynaecology, Pakistan Atomic Energy Commission (PAEC) General Hospital, Islamabad, from February to December 2009. Methodology: All patients needing 2nd dinoprostone pessary for induction of labour were included in the study. Patients with gestation below 37 weeks, those with intra-uterine growth restriction, bad obstetric history, previous uterine scar and patients in whom Bishop score improved for amniotomy after 1st dinoprostone pessary, were excluded. Data was collected on a special proforma where all variables were defined. Results:Out of 90 patients, 44 (48.8 percentage) had spontaneous vertex deliveries and 12 (13.3 percentage) had instrumental deliveries so a total vaginal deliveries occurred in 56 (62.2 percentage) patients. Thirty four patients (37.8 percentage) had emergency caesarean sections. Main indication for cesarean was failure to progress in 1st stage of labour followed by fetal distress. There were 3 failed inductions. Only 2 patients had hyperstimulation. NICU admission were 8 and all babies were discharged healthy from nursery with no case of early neonatal death. Conclusion:Concurrent oxytocin with 2nd dinoprostone in patients with poor Bishop scores (initial scores 2 and 3) resulted in more vaginal birth and comparatively shorter induction delivery time with almost negligible fetomaternal complications. (author)

  2. 39 CFR 273.7 - Concurrence of Attorney General.

    Science.gov (United States)

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Concurrence of Attorney General. 273.7 Section 273... PROGRAM FRAUD CIVIL REMEDIES ACT § 273.7 Concurrence of Attorney General. (a) The Attorney General is... the Attorney General or his designee approves such action in a written statement which specifies: (1...

  3. Transactions on Petri Nets and Other Models of Concurrency V

    DEFF Research Database (Denmark)

    submission track of ToPNoC. The 12 papers cover a diverse range of topics including model checking and system verification, synthesis, foundational work on specific classes of Petri nets, and innovative applications of Petri nets and other models of concurrency. Thus, this volume gives a good view of ongoing...... concurrent systems and Petri nets research...

  4. Gender asymmetry in concurrent partnerships and HIV prevalence

    NARCIS (Netherlands)

    Leung, Ka Yin; Powers, Kimberly A.; Kretzschmar, Mirjam

    The structure of the sexual network of a population plays an essential role in the transmission of HIV. Concurrent partnerships, i.e. partnerships that overlap in time, are important in determining this network structure. Men and women may differ in their concurrent behavior, e.g. in the case of

  5. Gender asymmetry in concurrent partnerships and HIV prevalence

    NARCIS (Netherlands)

    Leung, Ka Yin; Powers, Kimberly A.; Kretzschmar, Mirjam

    2017-01-01

    The structure of the sexual network of a population plays an essential role in the transmission of HIV. Concurrent partnerships, i.e. partnerships that overlap in time, are important in determining this network structure. Men and women may differ in their concurrent behavior, e.g. in the case of

  6. Dynamic Frames Based Verification Method for Concurrent Java Programs

    NARCIS (Netherlands)

    Mostowski, Wojciech

    2016-01-01

    In this paper we discuss a verification method for concurrent Java programs based on the concept of dynamic frames. We build on our earlier work that proposes a new, symbolic permission system for concurrent reasoning and we provide the following new contributions. First, we describe our approach

  7. Association of HIV prevalence and concurrency of sexual ...

    African Journals Online (AJOL)

    Association of HIV prevalence and concurrency of sexual partnerships in South Africa's language groups: An ecological analysis. C Kenyon. Abstract. Background. There is considerable variation in HIV prevalence between different language groups in South Africa (SA). Sexual partner concurrency has been linked to the ...

  8. Photostable nonlinear optical polycarbonates

    NARCIS (Netherlands)

    Faccini, M.; Balakrishnan, M.; Diemeer, Mart; Torosantucci, Riccardo; Driessen, A.; Reinhoudt, David; Verboom, Willem

    2008-01-01

    Highly thermal and photostable nonlinear optical polymers were obtained by covalently incorporating the tricyanovinylidenediphenylaminobenzene (TCVDPA) chromophore to a polycarbonate backbone. NLO polycarbonates with different chromophore attachment modes and flexibilities were synthesized. In spite

  9. Nonlinear singular elliptic equations

    International Nuclear Information System (INIS)

    Dong Minh Duc.

    1988-09-01

    We improve the Poincare inequality, the Sobolev imbedding theorem and the Trudinger imbedding theorem and prove a Mountain pass theorem. Applying these results we study a nonlinear singular mixed boundary problem. (author). 22 refs

  10. Nonlinear Optical Terahertz Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — We develop a new approach to generation of THz radiation. Our method relies on mixing two optical frequency beams in a nonlinear crystalline Whispering Gallery Mode...

  11. Nonlinear differential equations

    CERN Document Server

    Struble, Raimond A

    2017-01-01

    Detailed treatment covers existence and uniqueness of a solution of the initial value problem, properties of solutions, properties of linear systems, stability of nonlinear systems, and two-dimensional systems. 1962 edition.

  12. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz...... nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...... to a decrease of plasma frequency in semiconductor and produces a substantial modification of THz-range material dielectric function, described by the Drude model. As a result, the nonlinearity of both absorption coefficient and refractive index of the semiconductor is observed. In particular we demonstrate...

  13. Ultrafast nonlinear optics

    CERN Document Server

    Leburn, Christopher; Reid, Derryck

    2013-01-01

    The field of ultrafast nonlinear optics is broad and multidisciplinary, and encompasses areas concerned with both the generation and measurement of ultrashort pulses of light, as well as those concerned with the applications of such pulses. Ultrashort pulses are extreme events – both in terms of their durations, and also the high peak powers which their short durations can facilitate. These extreme properties make them powerful experiment tools. On one hand, their ultrashort durations facilitate the probing and manipulation of matter on incredibly short timescales. On the other, their ultrashort durations can facilitate high peak powers which can drive highly nonlinear light-matter interaction processes. Ultrafast Nonlinear Optics covers a complete range of topics, both applied and fundamental in nature, within the area of ultrafast nonlinear optics. Chapters 1 to 4 are concerned with the generation and measurement of ultrashort pulses. Chapters 5 to 7 are concerned with fundamental applications of ultrasho...

  14. Nonlinear surface Alfven waves

    International Nuclear Information System (INIS)

    Cramer, N.F.

    1991-01-01

    The problem of nonlinear surface Alfven waves propagating on an interface between a plasma and a vacuum is discussed, with dispersion provided by the finite-frequency effect, i.e. the finite ratio of the frequency to the ion-cyclotron frequency. A set of simplified nonlinear wave equations is derived using the method of stretched co-ordinates, and another approach uses the generation of a second-harmonic wave and its interaction with the first harmonic to obtain a nonlinear dispersion relation. A nonlinear Schroedinger equation is then derived, and soliton solutions found that propagate as solitary pulses in directions close to parallel and antiparallel to the background magnetic field. (author)

  15. Nonlinear Structural Analysis

    Indian Academy of Sciences (India)

    The Structures Panel of the Aeronautics Research and Development Board of India ... A great variety of topics was covered, including themes such as nonlinear finite ... or shell structures, and three are on the composite form of construction, ...

  16. A nonlinear oscillatory problem

    International Nuclear Information System (INIS)

    Zhou Qingqing.

    1991-10-01

    We have studied the nonlinear oscillatory problem of orthotropic cylindrical shell, we have analyzed the character of the oscillatory system. The stable condition of the oscillatory system has been given. (author). 6 refs

  17. Degenerate nonlinear diffusion equations

    CERN Document Server

    Favini, Angelo

    2012-01-01

    The aim of these notes is to include in a uniform presentation style several topics related to the theory of degenerate nonlinear diffusion equations, treated in the mathematical framework of evolution equations with multivalued m-accretive operators in Hilbert spaces. The problems concern nonlinear parabolic equations involving two cases of degeneracy. More precisely, one case is due to the vanishing of the time derivative coefficient and the other is provided by the vanishing of the diffusion coefficient on subsets of positive measure of the domain. From the mathematical point of view the results presented in these notes can be considered as general results in the theory of degenerate nonlinear diffusion equations. However, this work does not seek to present an exhaustive study of degenerate diffusion equations, but rather to emphasize some rigorous and efficient techniques for approaching various problems involving degenerate nonlinear diffusion equations, such as well-posedness, periodic solutions, asympt...

  18. Introduction to nonlinear science

    CERN Document Server

    Nicolis, G

    1995-01-01

    One of the most unexpected results in science in recent years is that quite ordinary systems obeying simple laws can give rise to complex, nonlinear or chaotic, behavior. In this book, the author presents a unified treatment of the concepts and tools needed to analyze nonlinear phenomena and to outline some representative applications drawn from the physical, engineering, and biological sciences. Some of the interesting topics covered include: dynamical systems with a finite number of degrees of freedom, linear stability analysis of fixed points, nonlinear behavior of fixed points, bifurcation analysis, spatially distributed systems, broken symmetries, pattern formation, and chaotic dynamics. The author makes a special effort to provide a logical connection between ordinary dynamical systems and spatially extended systems, and to balance the emphasis on chaotic behavior and more classical nonlinear behavior. He also develops a statistical approach to complex systems and compares it to traditional deterministi...

  19. Nonlinear Wave Propagation

    Science.gov (United States)

    2015-05-07

    associated with the lattice background; the nonlinearity is derived from the inclusion of cubic nonlinearity. Often the background potential is periodic...dispersion branch we can find discrete evolution equations for the envelope associated with the lattice NLS equation (1) by looking for solutions of...spatial operator in the above NLS equation can be elliptic, hyperbolic or parabolic . We remark that further reduction is possible by going into a moving

  20. Nonlinear dynamics and astrophysics

    International Nuclear Information System (INIS)

    Vallejo, J. C.; Sanjuan, M. A. F.

    2000-01-01

    Concepts and techniques from Nonlinear Dynamics, also known as Chaos Theory, have been applied successfully to several astrophysical fields such as orbital motion, time series analysis or galactic dynamics, providing answers to old questions but also opening a few new ones. Some of these topics are described in this review article, showing the basis of Nonlinear Dynamics, and how it is applied in Astrophysics. (Author)

  1. Pescara benchmarks: nonlinear identification

    Science.gov (United States)

    Gandino, E.; Garibaldi, L.; Marchesiello, S.

    2011-07-01

    Recent nonlinear methods are suitable for identifying large systems with lumped nonlinearities, but in practice most structural nonlinearities are distributed and an ideal nonlinear identification method should cater for them as well. In order to extend the current NSI method to be applied also on realistic large engineering structures, a modal counterpart of the method is proposed in this paper. The modal NSI technique is applied on one of the reinforced concrete beams that have been tested in Pescara, under the project titled "Monitoring and diagnostics of railway bridges by means of the analysis of the dynamic response due to train crossing", financed by Italian Ministry of Research. The beam showed a softening nonlinear behaviour, so that the nonlinearity concerning the first mode is characterized and its force contribution is quantified. Moreover, estimates for the modal parameters are obtained and the model is validated by comparing the measured and the reconstructed output. The identified estimates are also used to accurately predict the behaviour of the same beam, when subject to different initial conditions.

  2. Nonlinear Multiantenna Detection Methods

    Directory of Open Access Journals (Sweden)

    Chen Sheng

    2004-01-01

    Full Text Available A nonlinear detection technique designed for multiple-antenna assisted receivers employed in space-division multiple-access systems is investigated. We derive the optimal solution of the nonlinear spatial-processing assisted receiver for binary phase shift keying signalling, which we refer to as the Bayesian detector. It is shown that this optimal Bayesian receiver significantly outperforms the standard linear beamforming assisted receiver in terms of a reduced bit error rate, at the expense of an increased complexity, while the achievable system capacity is substantially enhanced with the advent of employing nonlinear detection. Specifically, when the spatial separation expressed in terms of the angle of arrival between the desired and interfering signals is below a certain threshold, a linear beamformer would fail to separate them, while a nonlinear detection assisted receiver is still capable of performing adequately. The adaptive implementation of the optimal Bayesian detector can be realized using a radial basis function network. Two techniques are presented for constructing block-data-based adaptive nonlinear multiple-antenna assisted receivers. One of them is based on the relevance vector machine invoked for classification, while the other on the orthogonal forward selection procedure combined with the Fisher ratio class-separability measure. A recursive sample-by-sample adaptation procedure is also proposed for training nonlinear detectors based on an amalgam of enhanced -means clustering techniques and the recursive least squares algorithm.

  3. Pescara benchmarks: nonlinear identification

    International Nuclear Information System (INIS)

    Gandino, E; Garibaldi, L; Marchesiello, S

    2011-01-01

    Recent nonlinear methods are suitable for identifying large systems with lumped nonlinearities, but in practice most structural nonlinearities are distributed and an ideal nonlinear identification method should cater for them as well. In order to extend the current NSI method to be applied also on realistic large engineering structures, a modal counterpart of the method is proposed in this paper. The modal NSI technique is applied on one of the reinforced concrete beams that have been tested in Pescara, under the project titled M onitoring and diagnostics of railway bridges by means of the analysis of the dynamic response due to train crossing , financed by Italian Ministry of Research. The beam showed a softening nonlinear behaviour, so that the nonlinearity concerning the first mode is characterized and its force contribution is quantified. Moreover, estimates for the modal parameters are obtained and the model is validated by comparing the measured and the reconstructed output. The identified estimates are also used to accurately predict the behaviour of the same beam, when subject to different initial conditions.

  4. Introduction to nonlinear acoustics

    Science.gov (United States)

    Bjørnø, Leif

    2010-01-01

    A brief review of the basic principles of fluid mechanics needed for development of linear and nonlinear ultrasonic concepts will be given. The fundamental equations of nonlinear ultrasonics will be derived and their physical properties explained. It will be shown how an originally monochromatic finite-amplitude ultrasonic wave, due to nonlinear effects, will distort during its propagation in time and space to form higher harmonics to its fundamental frequency. The concepts of shock formation will be presented. The material nonlinearity, described by the nonlinearity parameter B/A of the material, and the convective nonlinearity, described by the ultrasonic Mach Number, will be explained. Two procedures for determination of B/A will briefly be described and some B/A-values characterizing biological materials will be presented. Shock formation, described by use of the Goldberg Number,and Ultrasonic Saturation will be discussed.. An introduction to focused ultrasonic fields will be given and it will be shown how the ultrasonic intensity will vary axially and laterally in and near the focal region and how the field parameters of interest to biomedical applications may be described by use of the KZK-Model. Finally, an introduction will be given to the parametric acoustic array formed by mixing and interaction of two monochromatic, finite-amplitude ultrasonic waves in a liquid and the potentials of this mixing process in biomedical ultrasound will briefly be mentioned.

  5. Concurrent Electroconvulsive Therapy and Bupropion Treatment.

    Science.gov (United States)

    Takala, Christopher R; Leung, Jonathan G; Murphy, Lauren L; Geske, Jennifer R; Palmer, Brian A

    2017-09-01

    Bupropion is associated with a dose-dependent increased risk of seizures. Use of concomitant bupropion and electroconvulsive therapy (ECT) remains controversial because of an increased risk of prolonged seizures. This is the first systematic evaluation of the effect of bupropion on ECT. A case group (n = 119), patients treated with concomitant ECT and bupropion, was compared with an age and gender frequency-matched control group (n = 261), treated with only ECT. Electroconvulsive therapy treatment data including seizure length, number of treatments, and concurrent medications were extracted. Longitudinal mixed models examined ECT versus ECT + bupropion group differences over the course of treatments measured by seizure duration (electroencephalogram [EEG] and motor). Multivariable models examined the total number of treatments and first and last seizure duration. All models considered group differences with ECT treatment measures adjusted for age, gender, benzodiazepine treatment, lead placement, and setting. Electroconvulsive therapy treatment with bupropion led to shorter motor seizure duration (0.047) and EEG seizure duration (P = 0.001). The number of ECT treatments (7.3 vs 7.0 treatments; P = 0.23), respectively, or the probability of a prolonged seizure (P = 0.15) was not significantly different. Benzodiazepine use was significantly more common in control subjects (P = 0.01). This is a retrospective analysis limited in part by unavailable variables (seizure threshold, nature of EEG and motor seizure monitoring, type of ECT device, dosing and formulation of bupropion, and duration of the current depressive illness). This study revealed a significantly shorter duration in seizure length with ECT + concomitant bupropion, but not in the number of required treatments in those treated compared with ECT without bupropion. There remains a critical need to reevaluate the efficacy of concomitant use of psychotropic medications + ECT.

  6. Fundamentals of nonlinear optical materials

    Indian Academy of Sciences (India)

    Nonlinear optics; nonlinear polarization; optical fiber communication; optical switch- ing. PACS Nos 42.65Tg; ... The importance of nonlinear optics is to understand the nonlinear behavior in the induced polarization and to ..... but much work in material development and characterization remains to be done. 16. Conclusion.

  7. Nonlinear Approaches in Engineering Applications

    CERN Document Server

    Jazar, Reza

    2012-01-01

    Nonlinear Approaches in Engineering Applications focuses on nonlinear phenomena that are common in the engineering field. The nonlinear approaches described in this book provide a sound theoretical base and practical tools to design and analyze engineering systems with high efficiency and accuracy and with less energy and downtime. Presented here are nonlinear approaches in areas such as dynamic systems, optimal control and approaches in nonlinear dynamics and acoustics. Coverage encompasses a wide range of applications and fields including mathematical modeling and nonlinear behavior as applied to microresonators, nanotechnologies, nonlinear behavior in soil erosion,nonlinear population dynamics, and optimization in reducing vibration and noise as well as vibration in triple-walled carbon nanotubes. This book also: Provides a complete introduction to nonlinear behavior of systems and the advantages of nonlinearity as a tool for solving engineering problems Includes applications and examples drawn from the el...

  8. 50 years of nonlinear optics

    International Nuclear Information System (INIS)

    Shen Yuanrang

    2011-01-01

    This article presents a brief introduction to the birth and early investigations of nonlinear optics, such as second harmonic generation,sum and difference frequency generation, stimulated Raman scattering,and self-action of light etc. Several important research achievements and applications of nonlinear optics are presented as well, including nonlinear optical spectroscopy, phase conjugation and adaptive optics, coherent nonlinear optics, and high-order harmonic generation. In the end, current and future research topics in nonlinear optics are summarized. (authors)

  9. Data-centric concurrency control on the java programming language

    OpenAIRE

    Parreira, Daniel Luis Landeiroto

    2013-01-01

    Dissertação para obtenção do Grau de Mestre em Engenharia Informática The multi-core paradigm has propelled shared-memory concurrent programming to an important role in software development. Its use is however limited by the constructs that provide a layer of abstraction for synchronizing access to shared resources. Reasoning with these constructs is not trivial due to their concurrent nature. Data-races and deadlocks occur in concurrent programs, encumbering the programmer and furth...

  10. A Concurrent Distributed System for Aircraft Tactical Decision Generation

    Science.gov (United States)

    McManus, John W.

    1990-01-01

    A research program investigating the use of artificial intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range (WVR) air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of a concurrent version of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS) program, a second generation TDG, is presented. Concurrent computing environments and programming approaches are discussed and the design and performance of a prototype concurrent TDG system are presented.

  11. CONCURRENT VALIDITY OF THE STUDENT TEACHER PROFESSIONAL IDENTITY SCALE

    Directory of Open Access Journals (Sweden)

    Predrag Živković

    2018-04-01

    Full Text Available The main purpose of study was to examine concurrent validity of the Student Teachers Professional Identity Scale–STPIS (Fisherman and Abbot, 1998 that was for the first time used in Serbia. Indicators of concurrent validity was established by correlation with student teacher self-reported well-being, self-esteem, burnout stress and resilience. Based on the results we can conclude that the STPIS meets the criterion of concurrent validity. The implications of these results are important for researchers and decisions makers in teacher education

  12. Computational simulation of concurrent engineering for aerospace propulsion systems

    Science.gov (United States)

    Chamis, C. C.; Singhal, S. N.

    1992-01-01

    Results are summarized of an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulations methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties - fundamental in developing such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering for propulsion systems and systems in general. Benefits and facets needing early attention in the development are outlined.

  13. Computational simulation for concurrent engineering of aerospace propulsion systems

    Science.gov (United States)

    Chamis, C. C.; Singhal, S. N.

    1993-01-01

    Results are summarized for an investigation to assess the infrastructure available and the technology readiness in order to develop computational simulation methods/software for concurrent engineering. These results demonstrate that development of computational simulation methods for concurrent engineering is timely. Extensive infrastructure, in terms of multi-discipline simulation, component-specific simulation, system simulators, fabrication process simulation, and simulation of uncertainties--fundamental to develop such methods, is available. An approach is recommended which can be used to develop computational simulation methods for concurrent engineering of propulsion systems and systems in general. Benefits and issues needing early attention in the development are outlined.

  14. Neuromechanical tuning of nonlinear postural control dynamics

    Science.gov (United States)

    Ting, Lena H.; van Antwerp, Keith W.; Scrivens, Jevin E.; McKay, J. Lucas; Welch, Torrence D. J.; Bingham, Jeffrey T.; DeWeerth, Stephen P.

    2009-06-01

    Postural control may be an ideal physiological motor task for elucidating general questions about the organization, diversity, flexibility, and variability of biological motor behaviors using nonlinear dynamical analysis techniques. Rather than presenting "problems" to the nervous system, the redundancy of biological systems and variability in their behaviors may actually be exploited to allow for the flexible achievement of multiple and concurrent task-level goals associated with movement. Such variability may reflect the constant "tuning" of neuromechanical elements and their interactions for movement control. The problem faced by researchers is that there is no one-to-one mapping between the task goal and the coordination of the underlying elements. We review recent and ongoing research in postural control with the goal of identifying common mechanisms underlying variability in postural control, coordination of multiple postural strategies, and transitions between them. We present a delayed-feedback model used to characterize the variability observed in muscle coordination patterns during postural responses to perturbation. We emphasize the significance of delays in physiological postural systems, requiring the modulation and coordination of both the instantaneous, "passive" response to perturbations as well as the delayed, "active" responses to perturbations. The challenge for future research lies in understanding the mechanisms and principles underlying neuromechanical tuning of and transitions between the diversity of postural behaviors. Here we describe some of our recent and ongoing studies aimed at understanding variability in postural control using physical robotic systems, human experiments, dimensional analysis, and computational models that could be enhanced from a nonlinear dynamics approach.

  15. Nonlinear dynamics of structures

    CERN Document Server

    Oller, Sergio

    2014-01-01

    This book lays the foundation of knowledge that will allow a better understanding of nonlinear phenomena that occur in structural dynamics.   This work is intended for graduate engineering students who want to expand their knowledge on the dynamic behavior of structures, specifically in the nonlinear field, by presenting the basis of dynamic balance in non‐linear behavior structures due to the material and kinematics mechanical effects.   Particularly, this publication shows the solution of the equation of dynamic equilibrium for structure with nonlinear time‐independent materials (plasticity, damage and frequencies evolution), as well as those time dependent non‐linear behavior materials (viscoelasticity and viscoplasticity). The convergence conditions for the non‐linear dynamic structure solution  are studied, and the theoretical concepts and its programming algorithms are presented.  

  16. Nonlinear Dot Plots.

    Science.gov (United States)

    Rodrigues, Nils; Weiskopf, Daniel

    2018-01-01

    Conventional dot plots use a constant dot size and are typically applied to show the frequency distribution of small data sets. Unfortunately, they are not designed for a high dynamic range of frequencies. We address this problem by introducing nonlinear dot plots. Adopting the idea of nonlinear scaling from logarithmic bar charts, our plots allow for dots of varying size so that columns with a large number of samples are reduced in height. For the construction of these diagrams, we introduce an efficient two-way sweep algorithm that leads to a dense and symmetrical layout. We compensate aliasing artifacts at high dot densities by a specifically designed low-pass filtering method. Examples of nonlinear dot plots are compared to conventional dot plots as well as linear and logarithmic histograms. Finally, we include feedback from an expert review.

  17. Multidimensional nonlinear descriptive analysis

    CERN Document Server

    Nishisato, Shizuhiko

    2006-01-01

    Quantification of categorical, or non-numerical, data is a problem that scientists face across a wide range of disciplines. Exploring data analysis in various areas of research, such as the social sciences and biology, Multidimensional Nonlinear Descriptive Analysis presents methods for analyzing categorical data that are not necessarily sampled randomly from a normal population and often involve nonlinear relations. This reference not only provides an overview of multidimensional nonlinear descriptive analysis (MUNDA) of discrete data, it also offers new results in a variety of fields. The first part of the book covers conceptual and technical preliminaries needed to understand the data analysis in subsequent chapters. The next two parts contain applications of MUNDA to diverse data types, with each chapter devoted to one type of categorical data, a brief historical comment, and basic skills peculiar to the data types. The final part examines several problems and then concludes with suggestions for futu...

  18. Nonlinear Source Emulator

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem

    of a proposed NSE system with high dynamic performance. The goal of the work is to achieve a state-of-the art transient time of 10 µs. In order to produce the arbitrary nonlinear curve, the exponential function of a typical diode is used, but the diode can be replaced by other nonlinear curve reference...... of conductive common-mode current produced by the high rate of change of voltage over time (high dv/dt) at the NSE output. v/xvii The contributions of the thesis are based on the development of both units: the low Cio isolated power supply and the high dynamic performance NSE. Both units are investigated......-of-the-art dynamic performance among devices of the same kind. It also offers a complete solution for simulation of nonlinear source systems of different sizes, both in terrestrial and non-terrestrial applications. Key words: Current transformers, dc-dc power converters, hysteresis, parasitic capacitance, system...

  19. Nonlinear elastic waves in materials

    CERN Document Server

    Rushchitsky, Jeremiah J

    2014-01-01

    The main goal of the book is a coherent treatment of the theory of propagation in materials of nonlinearly elastic waves of displacements, which corresponds to one modern line of development of the nonlinear theory of elastic waves. The book is divided on five basic parts: the necessary information on waves and materials; the necessary information on nonlinear theory of elasticity and elastic materials; analysis of one-dimensional nonlinear elastic waves of displacement – longitudinal, vertically and horizontally polarized transverse plane nonlinear elastic waves of displacement; analysis of one-dimensional nonlinear elastic waves of displacement – cylindrical and torsional nonlinear elastic waves of displacement; analysis of two-dimensional nonlinear elastic waves of displacement – Rayleigh and Love nonlinear elastic surface waves. The book is addressed first of all to people working in solid mechanics – from the students at an advanced undergraduate and graduate level to the scientists, professional...

  20. Nonlinear excitations in biomolecules

    International Nuclear Information System (INIS)

    Peyrard, M.

    1995-01-01

    The aim of the workshop entitled ''Nonlinear Excitations in Biomolecules'' is to attempt to bridge the gap between the physicists and biologists communities which is mainly due to language and cultural barriers. The progress of nonlinear science in the last few decades which have shown that the combination of nonlinearity, which characterize most biological phenomena, and cooperative effects in a system having a large number of degrees of freedom, can give rise to coherent excitations with remarkable properties. New concepts, such as solitons nd nonlinear energy localisation have become familiar to physicists and applied mathematicians. It is thus tempting to make an analogy between these coherent excitations and the exceptional stability of some biological processes, such as for instance DNA transcription, which require the coordination of many events in the ever changing environment of a cell. Physicists are now invoking nonlinear excitations to describe and explain many bio-molecular processes while biologists often doubt that the seemingly infinite variety of phenomena that they are attempting to classify can be reduced to such simple concepts. A large part of the meeting is devoted to tutorial lectures rather than to latest research results. The book provides a pedagogical introduction to the two topics forming the backbone of the meeting: the theory of nonlinear excitations and solitons, and their application in biology; and the structure and function of biomolecules, as well as energy and charge transport in biophysics. In order to emphasize the link between physics and biology, the volume is not divided along these two topics but according to biological subjects. Each chapter starts with a short introduction attempting to help the reader to find his way among the contributions and point out the connection between them. 23 lectures over the 32 presented have been selected and refers to quantum properties of macro-molecules. (J.S.)

  1. A case for evaluating sensor network protocols concurrently

    KAUST Repository

    Gnawali, Omprakash; Guibas, Leonidas; Levis, Philip

    2010-01-01

    Researchers typically evaluate and compare protocols on the testbeds by running them one at a time. This methodology ignores the variation in link qualities and wireless environment across these experiments. These variations can introduce significant noise in the results. Evaluating two protocols concurrently, however, suffers from inter-protocol interactions. These interactions can perturb performance even under very light load, especially timing and timing sensitive protocols. We argue that the benefits of running protocols concurrently greatly outweigh the disadvantages. Protocols rarely run in isolation in real networks, and so considering such interactions is valuable. Although the wireless environment is still uncontrolled, concurrent evaluations make comparisons fair and more statistically sound. Through experiments on two testbeds, we make the case for evaluating and comparing low data-rate sensor network protocols by running them concurrently. Copyright 2010 ACM.

  2. Concurrency-Induced Transitions in Epidemic Dynamics on Temporal Networks.

    Science.gov (United States)

    Onaga, Tomokatsu; Gleeson, James P; Masuda, Naoki

    2017-09-08

    Social contact networks underlying epidemic processes in humans and animals are highly dynamic. The spreading of infections on such temporal networks can differ dramatically from spreading on static networks. We theoretically investigate the effects of concurrency, the number of neighbors that a node has at a given time point, on the epidemic threshold in the stochastic susceptible-infected-susceptible dynamics on temporal network models. We show that network dynamics can suppress epidemics (i.e., yield a higher epidemic threshold) when the node's concurrency is low, but can also enhance epidemics when the concurrency is high. We analytically determine different phases of this concurrency-induced transition, and confirm our results with numerical simulations.

  3. Concurrency-Induced Transitions in Epidemic Dynamics on Temporal Networks

    Science.gov (United States)

    Onaga, Tomokatsu; Gleeson, James P.; Masuda, Naoki

    2017-09-01

    Social contact networks underlying epidemic processes in humans and animals are highly dynamic. The spreading of infections on such temporal networks can differ dramatically from spreading on static networks. We theoretically investigate the effects of concurrency, the number of neighbors that a node has at a given time point, on the epidemic threshold in the stochastic susceptible-infected-susceptible dynamics on temporal network models. We show that network dynamics can suppress epidemics (i.e., yield a higher epidemic threshold) when the node's concurrency is low, but can also enhance epidemics when the concurrency is high. We analytically determine different phases of this concurrency-induced transition, and confirm our results with numerical simulations.

  4. A Concurrent Multiple Negotiation Protocol Based on Colored Petri Nets.

    Science.gov (United States)

    Niu, Lei; Ren, Fenghui; Zhang, Minjie; Bai, Quan

    2017-11-01

    Concurrent multiple negotiation (CMN) provides a mechanism for an agent to simultaneously conduct more than one negotiation. There may exist different interdependency relationships among these negotiations and these interdependency relationships can impact the outcomes of these negotiations. The outcomes of these concurrent negotiations contribute together for the agent to achieve an overall negotiation goal. Handling a CMN while considering interdependency relationships among multiple negotiations is a challenging research problem. This paper: 1) comprehensively highlights research problems of negotiations at concurrent negotiation level; 2) provides a graph-based CMN model with consideration of the interdependency relationships; and 3) proposes a colored Petri net-based negotiation protocol for conducting CMNs. With the proposed protocol, a CMN can be efficiently and concurrently processed and negotiation agreements can be efficiently achieved. Experimental results indicate the effectiveness and efficiency of the proposed protocol in terms of the negotiation success rate, the negotiation time and the negotiation outcome.

  5. Concurrent control system for the JAERI tandem accelerator

    International Nuclear Information System (INIS)

    Hanashima, Susumu; Shozi, Tokio; Shiozaki, Yasuo; Saito, Motoi; Oogane, Yasuo; Sekiguchi, Satoshi.

    1994-01-01

    A new control system for the JAERI tandem accelerator is constructed. The system utilizes concurrent processing technology with multiprocessor. Transputers are used both for central processor and I/O front end processors. (author)

  6. Love, lust and the emotional context of multiple and concurrent ...

    African Journals Online (AJOL)

    Love, lust and the emotional context of multiple and concurrent sexual partnerships among young Swazi adults. Allison Ruark, Lunga Dlamini, Nonhlanhla Mazibuko, Edward C Green, Caitlin Kennedy, Amy Nunn, Timothy Flanigan, Pamela J Surkan ...

  7. Partial Orders and Fully Abstract Models for Concurrency

    DEFF Research Database (Denmark)

    Engberg, Uffe Henrik

    1990-01-01

    In this thesis sets of labelled partial orders are employed as fundamental mathematical entities for modelling nondeterministic and concurrent processes thereby obtaining so-called noninterleaving semantics. Based on different closures of sets of labelled partial orders, simple algebraic language...

  8. Poverty and sexual concurrency: a case study of STI risk.

    Science.gov (United States)

    Tsui, Emma K; Leonard, Lori; Lenoir, Chavonne; Ellen, Jonathan M

    2008-08-01

    This paper is about sexual concurrency, or maintaining multiple sexual partnerships that overlap in time. Sexual concurrency is a concept that is used in the field of public health to explain the spread of sexually transmitted diseases. Sexual concurrency has also been proposed as a site of intervention to reduce sexually transmitted infection (STI) rates, particularly among those populations who carry the heaviest STI burden: adolescents and African Americans. In this paper, we use ethnographic data collected from a group of African American adolescents living in Baltimore to examine the socially produced configurations of risks and relationships that are obscured by the term sexual concurrency. The data we present show the limits of this concept, and suggest that structural reforms, including improvements to education, drug treatment, and work opportunities, are necessary to reduce racial disparities in STI rates.

  9. Prototyping of concurrent control systems implemented in FPGA devices

    CERN Document Server

    Wiśniewski, Remigiusz

    2017-01-01

    This book focuses on prototyping aspects of concurrent control systems and their further implementation and partial reconfiguration in programmable devices. Further, it lays out a full prototyping flow for concurrent control systems. Based on a given primary specification, a system is described with an interpreted Petri net, which naturally reflects the concurrent and sequential relationships of the design. The book shows that, apart from the traditional option of static configuration of the entire system, the latest programmable devices (especially FPGAs) offer far more sophistication. Partial reconfiguration allows selected parts of the system to be replaced without having to reprogram the entire structure of the device. Approaches to dynamic and static partial reconfiguration of concurrent control systems are presented and described in detail.< The theoretical work is illustrated by examples drawn from various applications, with a milling machine and a traffic-light controller highlighted as representat...

  10. Service-Oriented Synthesis of Distributed and Concurrent Protocol Specifications

    Directory of Open Access Journals (Sweden)

    Jehad Al Dallal

    2008-01-01

    Full Text Available Several methods have been proposed for synthesizing computer communication protocol specifications from service specifications. Some protocol synthesis methods based on the finite state machine (FSM model assume that primitives in the service specifications cannot be executed simultaneously. Others either handle only controlled primitive concurrency or have tight restrictions on the applicable FSM topologies. As a result, these synthesis methods are not applicable to an interesting variety of inherently concurrent applications, such as the Internet and mobile communication systems. This paper proposes a concurrent-based protocol synthesis method that eliminates the restrictions imposed by the earlier methods. The proposed method uses a synthesis method to obtain a sequential protocol specification (P-SPEC from a given service specification (S-SPEC. The resulting P-SPEC is then remodeled to consider the concurrency behavior specified in the S-SPEC, while guaranteeing that P-SPEC provides the specified service.

  11. Reliability and concurrent validity of an alternative method of lateral ...

    African Journals Online (AJOL)

    1 University of Northern Iowa, Division of Athletic Training, 003C Human. Performance Center, Cedar ... concurrent validity of the fingertip-to-floor distance test (FFD) ... in these protocols are spinal and extremity range of motion, pelvic control ...

  12. Context Aware Concurrent Execution Framework for Web Browser

    DEFF Research Database (Denmark)

    Saeed, Aamir; Erbad, Aiman Mahmood; Olsen, Rasmus Løvenstein

    Computing hungry multimedia web applications need to efficiently utilize the device resources. HTML5 web workers is a non-sharing concurrency platform that enables multimedia web application to utilize the available multi-core hardware. HTML5 web workers are implemented by major browser vendors...... to facilitate concurrent execution in web clients and enhance the quality of ambitious web applications. The concurrent execution in web workers allows parallel processing using available cores at the expense of communication overhead and extra computation. The benefits of concurrent execution can be maximized...... by balancing load across workers/CPU cores. This work presents load-balancing algorithms between web workers using parameters such as scheduler throughput, computation priority and game entity locality. An award-winning web-based multimedia game (raptjs.com) is used to test the performance of the load balance...

  13. Oscillations in nonlinear systems

    CERN Document Server

    Hale, Jack K

    2015-01-01

    By focusing on ordinary differential equations that contain a small parameter, this concise graduate-level introduction to the theory of nonlinear oscillations provides a unified approach to obtaining periodic solutions to nonautonomous and autonomous differential equations. It also indicates key relationships with other related procedures and probes the consequences of the methods of averaging and integral manifolds.Part I of the text features introductory material, including discussions of matrices, linear systems of differential equations, and stability of solutions of nonlinear systems. Pa

  14. Nonlinearity in nanomechanical cantilevers

    DEFF Research Database (Denmark)

    Villanueva Torrijo, Luis Guillermo; Karabalin, R. B.; Matheny, M. H.

    2013-01-01

    Euler-Bernoulli beam theory is widely used to successfully predict the linear dynamics of micro-and nanocantilever beams. However, its capacity to characterize the nonlinear dynamics of these devices has not yet been rigorously assessed, despite its use in nanoelectromechanical systems developmen....... These findings underscore the delicate balance between inertial and geometric nonlinear effects in the fundamental mode, and strongly motivate further work to develop theories beyond the Euler-Bernoulli approximation. DOI: 10.1103/PhysRevB.87.024304...

  15. Coupled nonlinear oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Chandra, J; Scott, A C

    1983-01-01

    Topics discussed include transitions in weakly coupled nonlinear oscillators, singularly perturbed delay-differential equations, and chaos in simple laser systems. Papers are presented on truncated Navier-Stokes equations in a two-dimensional torus, on frequency locking in Josephson point contacts, and on soliton excitations in Josephson tunnel junctions. Attention is also given to the nonlinear coupling of radiation pulses to absorbing anharmonic molecular media, to aspects of interrupted coarse-graining in stimulated excitation, and to a statistical analysis of long-term dynamic irregularity in an exactly soluble quantum mechanical model.

  16. Nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2012-01-01

    Since the 4e appeared, a fast evolution of the field has occurred. The 5e of this classic work provides an up-to-date account of the nonlinear phenomena occurring inside optical fibers, the basis of all our telecommunications infastructure as well as being used in the medical field. Reflecting the big developments in research, this new edition includes major new content: slow light effects, which offers a reduction in noise and power consumption and more ordered network traffic-stimulated Brillouin scattering; vectorial treatment of highly nonlinear fibers; and a brand new chapter o

  17. Reference Capabilities for Trait Based Reuse and Concurrency Control

    OpenAIRE

    Castegren, Elias; Wrigstad, Tobias

    2016-01-01

    The proliferation of shared mutable state in object-orientedprogramming complicates software development as two seeminglyunrelated operations may interact via an alias and produceunexpected results. In concurrent programming this manifestsitself as data-races. Concurrent object-oriented programming further suffers from thefact that code that warrants synchronisation cannot easily bedistinguished from code that does not. The burden is placed solelyon the programmer to reason about alias freedo...

  18. Concurrent object-oriented programming: The MP-Eiffel approach

    OpenAIRE

    Silva, Miguel Augusto Mendes Oliveira e

    2004-01-01

    This article evaluates several possible approaches for integrating concurrency into object-oriented programming languages, presenting afterwards, a new language named MP-Eiffel. MP-Eiffel was designed attempting to include all the essential properties of both concurrent and object-oriented programming with simplicity and safety. A special care was taken to achieve the orthogonality of all the language mechanisms, allowing their joint use without unsafe side-effects (such as inh...

  19. Time concurrency/phase-time synchronization in digital communications networks

    Science.gov (United States)

    Kihara, Masami; Imaoka, Atsushi

    1990-01-01

    Digital communications networks have the intrinsic capability of time synchronization which makes it possible for networks to supply time signals to some applications and services. A practical estimation method for the time concurrency on terrestrial networks is presented. By using this method, time concurrency capability of the Nippon Telegraph and Telephone Corporation (NTT) digital communications network is estimated to be better than 300 ns rms at an advanced level, and 20 ns rms at final level.

  20. An Automation-Assisted Empirical Study on Lock Usage for Concurrent Programs

    OpenAIRE

    Xin Rui; Qi Zhengwei; Huang Shiqiu; Xiang Chengcheng; Zheng Yudi; Wang Yin; Guan Haibing

    2013-01-01

    Nowadays concurrent programs are becoming more and more important with the development of hardware and network technologies. However it is not easy for programmers to write reliable concurrent programs. Concurrency characteristics such as thread interleaving make it difficult to debug or maintain concurrent programs. Although there are lots of research work on concurrency such as multi thread testing tools concurrent program verification and data race detection all of them leave open problems...

  1. Concurrent eruptions at Etna, Stromboli, and Vulcano: casualty or causality?

    Directory of Open Access Journals (Sweden)

    R. Funiciello

    2008-06-01

    Full Text Available Anecdotes of concurrent eruptions at Etna, Stromboli, and Vulcano (Southern Italy have persisted for more than 2000 years and volcanologists in recent and past times have hypothesized a causal link among these volcanoes. Here this hypothesis is tested. To introduce the problem and provide examples of the type of expected volcanic phenomena, narratives of the most notable examples of concurrent eruptions are provided. Then the frequency of eruptions at each individual volcano is analysed for about the last 300 years and the expected probability of concurrent eruptions is calculated to compare it to the observed probability. Results show that the occurrence of concurrent eruptions is often more frequent than a random probability, particularly for the Stromboli-Vulcano pair. These results are integrated with a statistical analysis of the earthquake catalogue to find evidence of linked seismicity in the Etnean and Aeolian areas. Results suggest a moderate incidence of non-random concurrent eruptions, but available data are temporally limited and do not allow an unequivocal identification of plausible triggers; our results, however, are the first attempt to quantify a more-than-2000-years-old curious observation and constitute a starting point for more sophisticated analyses of new data in the future. We look forward to our prediction of a moderate incidence of concurrent eruptions being confirmed or refuted with the passage of time and occurrence of new events.

  2. Risk factors for concurrent bacteremia in adult patients with dengue.

    Science.gov (United States)

    Thein, Tun-Linn; Ng, Ee-Ling; Yeang, Ming S; Leo, Yee-Sin; Lye, David C

    2017-06-01

    Bacteremia in dengue may occur with common exposure to pathogens in association with severe organ impairment or severe dengue, which may result in death. Cohort studies identifying risk factors for concurrent bacteremia among patients with dengue are rare. We conducted a retrospective case-control study of adult patients with dengue who were admitted to the Department of Infectious Diseases at Tan Tock Seng Hospital, Singapore from 2004 to 2008. For each case of dengue with concurrent bacteremia (within the first 72 hours of admission), we selected four controls without bacteremia, who were matched on year of infection and dengue confirmation method. Conditional logistic regression was performed to identify risk factors for concurrent bacteremia. Among 9,553 patients with dengue, 29 (0.3%) had bacteremia. Eighteen of these patients (62.1%) had concurrent bacteremia. The predominant bacteria were Staphylococcus aureus, one of which was a methicillin-resistant strain. Dengue shock syndrome occurred more frequently and hospital stay was longer among cases than among controls. Three cases did not survive, whereas none of the controls died. In multivariate analysis, being critically ill at hospital presentation was independently associated with 15 times the likelihood of a patient with dengue having concurrent bacteremia. Concurrent bacteremia in adult patients with dengue is uncommon but presents atypically and results in more deaths and longer hospital stay. Given the associated mortality, collection of blood cultures and empiric antibiotic therapy may be considered in patients who are critically ill. Copyright © 2015. Published by Elsevier B.V.

  3. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  4. Nonlinear Regression with R

    CERN Document Server

    Ritz, Christian; Parmigiani, Giovanni

    2009-01-01

    R is a rapidly evolving lingua franca of graphical display and statistical analysis of experiments from the applied sciences. This book provides a coherent treatment of nonlinear regression with R by means of examples from a diversity of applied sciences such as biology, chemistry, engineering, medicine and toxicology.

  5. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  6. Generalized Nonlinear Yule Models

    Science.gov (United States)

    Lansky, Petr; Polito, Federico; Sacerdote, Laura

    2016-11-01

    With the aim of considering models related to random graphs growth exhibiting persistent memory, we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macroevolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth rates. Among the main results we derive the explicit distribution of the number of in-links of a webpage chosen uniformly at random recognizing the contribution to the asymptotics and the finite time correction. The mean value of the latter distribution is also calculated explicitly in the most general case. Furthermore, in order to show the usefulness of our results, we particularize them in the case of specific birth rates giving rise to a saturating behaviour, a property that is often observed in nature. The further specialization to the non-fractional case allows us to extend the Yule model accounting for a nonlinear growth.

  7. Intramolecular and nonlinear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Davis, M.J. [Argonne National Laboratory, IL (United States)

    1993-12-01

    Research in this program focuses on three interconnected areas. The first involves the study of intramolecular dynamics, particularly of highly excited systems. The second area involves the use of nonlinear dynamics as a tool for the study of molecular dynamics and complex kinetics. The third area is the study of the classical/quantum correspondence for highly excited systems, particularly systems exhibiting classical chaos.

  8. Balancing for nonlinear systems

    NARCIS (Netherlands)

    Scherpen, J.M.A.

    1993-01-01

    We present a method of balancing for nonlinear systems which is an extension of balancing for linear systems in the sense that it is based on the input and output energy of a system. It is a local result, but gives 'broader' results than we obtain by just linearizing the system. Furthermore, the

  9. Identification of nonlinear anelastic models

    International Nuclear Information System (INIS)

    Draganescu, G E; Bereteu, L; Ercuta, A

    2008-01-01

    A useful nonlinear identification technique applied to the anelastic and rheologic models is presented in this paper. First introduced by Feldman, the method is based on the Hilbert transform, and is currently used for identification of the nonlinear vibrations

  10. Nonlinear chaos control and synchronization

    NARCIS (Netherlands)

    Huijberts, H.J.C.; Nijmeijer, H.; Schöll, E.; Schuster, H.G.

    2007-01-01

    This chapter contains sections titled: Introduction Nonlinear Geometric Control Some Differential Geometric Concepts Nonlinear Controllability Chaos Control Through Feedback Linearization Chaos Control Through Input-Output Linearization Lyapunov Design Lyapunov Stability and Lyapunov's First Method

  11. Nonlinearity and disorder: Classification and stability of nonlinear impurity modes

    DEFF Research Database (Denmark)

    Sukhorukov, Andrey A.; Kivshar, Yuri S.; Bang, Ole

    2001-01-01

    We study the effects produced by competition of two physical mechanisms of energy localization in inhomogeneous nonlinear systems. As an example, we analyze spatially localized modes supported by a nonlinear impurity in the generalized nonlinear Schrödinger equation and describe three types of no...... the case of a power-law nonlinearity in detail. We discuss several scenarios of the instability-induced dynamics of the nonlinear impurity modes, including the mode decay or switching to a new stable state, and collapse at the impurity site....

  12. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...... breathing of a single-cycle THz pulse in a semiconductor....

  13. FRF decoupling of nonlinear systems

    Science.gov (United States)

    Kalaycıoğlu, Taner; Özgüven, H. Nevzat

    2018-03-01

    Structural decoupling problem, i.e. predicting dynamic behavior of a particular substructure from the knowledge of the dynamics of the coupled structure and the other substructure, has been well investigated for three decades and led to several decoupling methods. In spite of the inherent nonlinearities in a structural system in various forms such as clearances, friction and nonlinear stiffness, all decoupling studies are for linear systems. In this study, decoupling problem for nonlinear systems is addressed for the first time. A method, named as FRF Decoupling Method for Nonlinear Systems (FDM-NS), is proposed for calculating FRFs of a substructure decoupled from a coupled nonlinear structure where nonlinearity can be modeled as a single nonlinear element. Depending on where nonlinear element is, i.e., either in the known or unknown subsystem, or at the connection point, the formulation differs. The method requires relative displacement information between two end points of the nonlinear element, in addition to point and transfer FRFs at some points of the known subsystem. However, it is not necessary to excite the system from the unknown subsystem even when the nonlinear element is in that subsystem. The validation of FDM-NS is demonstrated with two different case studies using nonlinear lumped parameter systems. Finally, a nonlinear experimental test structure is used in order to show the real-life application and accuracy of FDM-NS.

  14. Rogue waves in nonlinear science

    International Nuclear Information System (INIS)

    Yan Zhenya

    2012-01-01

    Rogue waves, as a special type of solitary waves, play an important role in nonlinear optics, Bose-Einstein condensates, ocean, atmosphere, and even finance. In this report, we mainly review on the history of the rogue wave phenomenon and recent development of rogue wave solutions in some nonlinear physical models arising in the fields of nonlinear science.

  15. H∞ Balancing for Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, Jacquelien M.A.

    1996-01-01

    In previously obtained balancing methods for nonlinear systems a past and a future energy function are used to bring the nonlinear system in balanced form. By considering a different pair of past and future energy functions that are related to the H∞ control problem for nonlinear systems we define

  16. Nonlinear differential equations

    Energy Technology Data Exchange (ETDEWEB)

    Dresner, L.

    1988-01-01

    This report is the text of a graduate course on nonlinear differential equations given by the author at the University of Wisconsin-Madison during the summer of 1987. The topics covered are: direction fields of first-order differential equations; the Lie (group) theory of ordinary differential equations; similarity solutions of second-order partial differential equations; maximum principles and differential inequalities; monotone operators and iteration; complementary variational principles; and stability of numerical methods. The report should be of interest to graduate students, faculty, and practicing scientists and engineers. No prior knowledge is required beyond a good working knowledge of the calculus. The emphasis is on practical results. Most of the illustrative examples are taken from the fields of nonlinear diffusion, heat and mass transfer, applied superconductivity, and helium cryogenics.

  17. Nonlinear (Anharmonic Casimir Oscillator

    Directory of Open Access Journals (Sweden)

    Habibollah Razmi

    2011-01-01

    Full Text Available We want to study the dynamics of a simple linear harmonic micro spring which is under the influence of the quantum Casimir force/pressure and thus behaves as a (an nonlinear (anharmonic Casimir oscillator. Generally, the equation of motion of this nonlinear micromechanical Casimir oscillator has no exact solvable (analytical solution and the turning point(s of the system has (have no fixed position(s; however, for particular values of the stiffness of the micro spring and at appropriately well-chosen distance scales and conditions, there is (are approximately sinusoidal solution(s for the problem (the variable turning points are collected in a very small interval of positions. This, as a simple and elementary plan, may be useful in controlling the Casimir stiction problem in micromechanical devices.

  18. Limits to Nonlinear Inversion

    DEFF Research Database (Denmark)

    Mosegaard, Klaus

    2012-01-01

    For non-linear inverse problems, the mathematical structure of the mapping from model parameters to data is usually unknown or partly unknown. Absence of information about the mathematical structure of this function prevents us from presenting an analytical solution, so our solution depends on our......-heuristics are inefficient for large-scale, non-linear inverse problems, and that the 'no-free-lunch' theorem holds. We discuss typical objections to the relevance of this theorem. A consequence of the no-free-lunch theorem is that algorithms adapted to the mathematical structure of the problem perform more efficiently than...... pure meta-heuristics. We study problem-adapted inversion algorithms that exploit the knowledge of the smoothness of the misfit function of the problem. Optimal sampling strategies exist for such problems, but many of these problems remain hard. © 2012 Springer-Verlag....

  19. Nonlinear Photonics 2014: introduction.

    Science.gov (United States)

    Akhmediev, N; Kartashov, Yaroslav

    2015-01-12

    International Conference "Nonlinear Photonics-2014" took place in Barcelona, Spain on July 27-31, 2014. It was a part of the "Advanced Photonics Congress" which is becoming a traditional notable event in the world of photonics. The current focus issue of Optics Express contains contributions from the participants of the Conference and the Congress. The articles in this focus issue by no means represent the total number of the congress contributions (around 400). However, it demonstrates wide range of topics covered at the event. The next conference of this series is to be held in 2016 in Australia, which is the home of many researchers working in the field of photonics in general and nonlinear photonics in particular.

  20. Nonlinear data assimilation

    CERN Document Server

    Van Leeuwen, Peter Jan; Reich, Sebastian

    2015-01-01

    This book contains two review articles on nonlinear data assimilation that deal with closely related topics but were written and can be read independently. Both contributions focus on so-called particle filters. The first contribution by Jan van Leeuwen focuses on the potential of proposal densities. It discusses the issues with present-day particle filters and explorers new ideas for proposal densities to solve them, converging to particle filters that work well in systems of any dimension, closing the contribution with a high-dimensional example. The second contribution by Cheng and Reich discusses a unified framework for ensemble-transform particle filters. This allows one to bridge successful ensemble Kalman filters with fully nonlinear particle filters, and allows a proper introduction of localization in particle filters, which has been lacking up to now.

  1. Essentials of nonlinear optics

    CERN Document Server

    Murti, Y V G S

    2014-01-01

    Current literature on Nonlinear Optics varies widely in terms of content, style, and coverage of specific topics, relative emphasis of areas and the depth of treatment. While most of these books are excellent resources for the researchers, there is a strong need for books appropriate for presenting the subject at the undergraduate or postgraduate levels in Universities. The need for such a book to serve as a textbook at the level of the bachelors and masters courses was felt by the authors while teaching courses on nonlinear optics to students of both science and engineering during the past two decades. This book has emerged from an attempt to address the requirement of presenting the subject at college level. A one-semester course covering the essentials can effectively be designed based on this.

  2. Nonlinear differential equations

    International Nuclear Information System (INIS)

    Dresner, L.

    1988-01-01

    This report is the text of a graduate course on nonlinear differential equations given by the author at the University of Wisconsin-Madison during the summer of 1987. The topics covered are: direction fields of first-order differential equations; the Lie (group) theory of ordinary differential equations; similarity solutions of second-order partial differential equations; maximum principles and differential inequalities; monotone operators and iteration; complementary variational principles; and stability of numerical methods. The report should be of interest to graduate students, faculty, and practicing scientists and engineers. No prior knowledge is required beyond a good working knowledge of the calculus. The emphasis is on practical results. Most of the illustrative examples are taken from the fields of nonlinear diffusion, heat and mass transfer, applied superconductivity, and helium cryogenics

  3. The forced nonlinear Schroedinger equation

    International Nuclear Information System (INIS)

    Kaup, D.J.; Hansen, P.J.

    1985-01-01

    The nonlinear Schroedinger equation describes the behaviour of a radio frequency wave in the ionosphere near the reflexion point where nonlinear processes are important. A simple model of this phenomenon leads to the forced nonlinear Schroedinger equation in terms of a nonlinear boundary value problem. A WKB analysis of the time evolution equations for the nonlinear Schroedinger equation in the inverse scattering transform formalism gives a crude order of magnitude estimation of the qualitative behaviour of the solutions. This estimation is compared with the numerical solutions. (D.Gy.)

  4. Nonlinear electrodynamics and cosmology

    International Nuclear Information System (INIS)

    Breton, Nora

    2010-01-01

    Nonlinear electrodynamics (NLED) generalizes Maxwell's theory for strong fields. When coupled to general relativity NLED presents interesting features like the non-vanishing of the trace of the energy-momentum tensor that leads to the possibility of violation of some energy conditions and of acting as a repulsive contribution in the Raychaudhuri equation. This theory is worth to study in cosmological and astrophysical situations characterized by strong electromagnetic and gravitational fields.

  5. Nonlinear fibre optics overview

    DEFF Research Database (Denmark)

    Travers, J. C.; Frosz, Michael Henoch; Dudley, J. M.

    2010-01-01

    The optical fiber based supercontinuum source has recently become a significant scientific and commercial success, with applications ranging from frequency comb production to advanced medical imaging. This one-of-a-kind book explains the theory of fiber supercontinuum broadening, describes......, provides a background to the associated nonlinear optical processes, treats the generation mechanisms from continuous wave to femtosecond pulse pump regimes and highlights the diverse applications. A full discussion of numerical methods and comprehensive computer code are also provided, enabling readers...

  6. Damped nonlinear Schrodinger equation

    International Nuclear Information System (INIS)

    Nicholson, D.R.; Goldman, M.V.

    1976-01-01

    High frequency electrostatic plasma oscillations described by the nonlinear Schrodinger equation in the presence of damping, collisional or Landau, are considered. At early times, Landau damping of an initial soliton profile results in a broader, but smaller amplitude soliton, while collisional damping reduces the soliton size everywhere; soliton speeds at early times are unchanged by either kind of damping. For collisional damping, soliton speeds are unchanged for all time

  7. Nonlinearity without superluminality

    International Nuclear Information System (INIS)

    Kent, Adrian

    2005-01-01

    Quantum theory is compatible with special relativity. In particular, though measurements on entangled systems are correlated in a way that cannot be reproduced by local hidden variables, they cannot be used for superluminal signaling. As Czachor, Gisin, and Polchinski pointed out, this is not generally true of general nonlinear modifications of the Schroedinger equation. Excluding superluminal signaling has thus been taken to rule out most nonlinear versions of quantum theory. The no-superluminal-signaling constraint has also been used for alternative derivations of the optimal fidelities attainable for imperfect quantum cloning and other operations. These results apply to theories satisfying the rule that their predictions for widely separated and slowly moving entangled systems can be approximated by nonrelativistic equations of motion with respect to a preferred time coordinate. This paper describes a natural way in which this rule might fail to hold. In particular, it is shown that quantum readout devices which display the values of localized pure states need not allow superluminal signaling, provided that the devices display the values of the states of entangled subsystems as defined in a nonstandard, although natural, way. It follows that any locally defined nonlinear evolution of pure states can be made consistent with Minkowski causality

  8. Multigrid Reduction in Time for Nonlinear Parabolic Problems

    Energy Technology Data Exchange (ETDEWEB)

    Falgout, R. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Manteuffel, T. A. [Univ. of Colorado, Boulder, CO (United States); O' Neill, B. [Univ. of Colorado, Boulder, CO (United States); Schroder, J. B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-01-04

    The need for parallel-in-time is being driven by changes in computer architectures, where future speed-ups will be available through greater concurrency, but not faster clock speeds, which are stagnant.This leads to a bottleneck for sequential time marching schemes, because they lack parallelism in the time dimension. Multigrid Reduction in Time (MGRIT) is an iterative procedure that allows for temporal parallelism by utilizing multigrid reduction techniques and a multilevel hierarchy of coarse time grids. MGRIT has been shown to be effective for linear problems, with speedups of up to 50 times. The goal of this work is the efficient solution of nonlinear problems with MGRIT, where efficient is defined as achieving similar performance when compared to a corresponding linear problem. As our benchmark, we use the p-Laplacian, where p = 4 corresponds to a well-known nonlinear diffusion equation and p = 2 corresponds to our benchmark linear diffusion problem. When considering linear problems and implicit methods, the use of optimal spatial solvers such as spatial multigrid imply that the cost of one time step evaluation is fixed across temporal levels, which have a large variation in time step sizes. This is not the case for nonlinear problems, where the work required increases dramatically on coarser time grids, where relatively large time steps lead to worse conditioned nonlinear solves and increased nonlinear iteration counts per time step evaluation. This is the key difficulty explored by this paper. We show that by using a variety of strategies, most importantly, spatial coarsening and an alternate initial guess to the nonlinear time-step solver, we can reduce the work per time step evaluation over all temporal levels to a range similar with the corresponding linear problem. This allows for parallel scaling behavior comparable to the corresponding linear problem.

  9. Concurrent sexual partners-A predictor of Chlamydia

    DEFF Research Database (Denmark)

    Jørgensen, Marianne Johansson; Olesen, Frede; Maindal, Helle Terkildsen

    2013-01-01

    , but the significance of this compared with other well-known predictors has only been briefly described. Aim: The aim is to examine if concurrent partners isan independent predictor for C. trachomatis infection in young Danes aged 15-29 years. Methods: Detailed sexual behavior data were collected via a web......:These preliminary results suggest that concurrent sexual partners is an important predictor for C.trachomatis infections among young Danes aged 15-29. A more concise conclusion will be presented at the Ph.D day......Background:Chlamydia trachomatis is the most common sexually transmitted bacterial infection among young Danes and the spread is highly dependent on the population’s sexual behavior. Previous studies have found concurrent partnerships to be a possible predictor for C. trachomatis...

  10. Mathematical techniques for analyzing concurrent and probabilistic systems

    CERN Document Server

    Rutten, J J M M; Panangaden, Prakash; Panangaden, Prakash; Breugel, Franck van

    2004-01-01

    The book consists of two sets of lecture notes devoted to slightly different methods of analysis of concurrent and probabilistic computational systems. The first set of lectures develops a calculus of streams (a generalization of the set of natural numbers) based on the coinduction principle coming from the theory of coalgebras. It is now well understood that the interplay between algebra (for describing structure) and coalgebra (for describing dynamics) is crucial for understanding concurrent systems. There is a striking analogy between streams and formula calculus reminiscent to those appearing in quantum calculus. These lecture notes will appeal to anyone working in concurrency theory but also to algebraists and logicians. The other set of lecture notes focuses on methods for automatically verifying probabilistic systems using techniques of model checking. The unique aspect of these lectures is the coverage of both theory and practice. The authors have been responsible for one of the most successful experi...

  11. How Formal Dynamic Verification Tools Facilitate Novel Concurrency Visualizations

    Science.gov (United States)

    Aananthakrishnan, Sriram; Delisi, Michael; Vakkalanka, Sarvani; Vo, Anh; Gopalakrishnan, Ganesh; Kirby, Robert M.; Thakur, Rajeev

    With the exploding scale of concurrency, presenting valuable pieces of information collected by formal verification tools intuitively and graphically can greatly enhance concurrent system debugging. Traditional MPI program debuggers present trace views of MPI program executions. Such views are redundant, often containing equivalent traces that permute independent MPI calls. In our ISP formal dynamic verifier for MPI programs, we present a collection of alternate views made possible by the use of formal dynamic verification. Some of ISP’s views help pinpoint errors, some facilitate discerning errors by eliminating redundancy, while others help understand the program better by displaying concurrent even orderings that must be respected by all MPI implementations, in the form of completes-before graphs. In this paper, we describe ISP’s graphical user interface (GUI) capabilities in all these areas which are currently supported by a portable Java based GUI, a Microsoft Visual Studio GUI, and an Eclipse based GUI whose development is in progress.

  12. Contemporary considerations in concurrent endoscopic sinus surgery and rhinoplasty.

    Science.gov (United States)

    Steele, Toby O; Gill, Amarbir; Tollefson, Travis T

    2018-06-11

    Characterize indications, perioperative considerations, clinical outcomes and complications for concurrent endoscopic sinus surgery (ESS) and rhinoplasty. Chronic rhinosinusitis and septal deviation with or without inferior turbinate hypertrophy independently impair patient-reported quality of life. Guidelines implore surgeons to include endoscopy to accurately evaluate patient symptoms. Complication rates parallel those of either surgery (ESS and rhinoplasty) alone and are not increased when performed concurrently. Operative time is generally longer for joint surgeries. Patient satisfaction rates are high. Concurrent functional and/or cosmetic rhinoplasty and ESS is a safe endeavor to perform in a single operative setting and most outcomes data suggest excellent patient outcomes. Additional studies that include patient-reported outcome measures are needed.

  13. Engineering Bereitschaft as an enabler for Concurrent Engineering

    DEFF Research Database (Denmark)

    Christiansen, Kåre; Vesterager, Johan

    1999-01-01

    Industrial companies observe a general trend towards more customised products and shorter product life cycles. Furthermore, the market demands shorter lead-time and high-quality products at a competitive price. Concurrent Engineering address these challenges. Product modelling is a key aspect...... of the Concurrent Engineering literature. One problem with the product modelling literature is that it tends to assume that product development is revolutionary. Very often product development is evolutionary and it means that product modelling should have a major emphasis on reuse. In this paper it is suggested...... that industrial companies should develop an engineering development Bereitschaft (preparatory engineering knowledge) as an approach to Concurrent Engineering and product modelling. To develop such an engineering development Bereitschaft, a company must develop company generic product models.This paper...

  14. How Do Developers Use APIs? A Case Study in Concurrency

    DEFF Research Database (Denmark)

    Blom, Stefan; Kiniry, Joseph; Huisman, Marieke

    2013-01-01

    and functionalities of the Java concurrency library java. util. concurrent. It discusses the Histogram tool that we developed for this purpose, i.e., to efficiently analyse a large collection of bytecode classes. The Histogram tool is used on a representative benchmark set, the Qualitas Corpus. The paper discusses...... the results of the analysis of this benchmark set in detail. This covers both an analysis of the important classes and methods used by the current releases of the benchmark collection, as well as an analysis of the time it took for the Java concurrency library to start being used in released software....... of static analysis and verification tools this information is highly important, because it indicates where and how to put the most efficient effort in annotating APIs, to make them usable for the static analysis and verification tools. This paper presents an analysis of the usage of the routines...

  15. Concurrent negotiation and coordination for grid resource coallocation.

    Science.gov (United States)

    Sim, Kwang Mong; Shi, Benyun

    2010-06-01

    Bolstering resource coallocation is essential for realizing the Grid vision, because computationally intensive applications often require multiple computing resources from different administrative domains. Given that resource providers and consumers may have different requirements, successfully obtaining commitments through concurrent negotiations with multiple resource providers to simultaneously access several resources is a very challenging task for consumers. The impetus of this paper is that it is one of the earliest works that consider a concurrent negotiation mechanism for Grid resource coallocation. The concurrent negotiation mechanism is designed for 1) managing (de)commitment of contracts through one-to-many negotiations and 2) coordination of multiple concurrent one-to-many negotiations between a consumer and multiple resource providers. The novel contributions of this paper are devising 1) a utility-oriented coordination (UOC) strategy, 2) three classes of commitment management strategies (CMSs) for concurrent negotiation, and 3) the negotiation protocols of consumers and providers. Implementing these ideas in a testbed, three series of experiments were carried out in a variety of settings to compare the following: 1) the CMSs in this paper with the work of others in a single one-to-many negotiation environment for one resource where decommitment is allowed for both provider and consumer agents; 2) the performance of the three classes of CMSs in different resource market types; and 3) the UOC strategy with the work of others [e.g., the patient coordination strategy (PCS )] for coordinating multiple concurrent negotiations. Empirical results show the following: 1) the UOC strategy achieved higher utility, faster negotiation speed, and higher success rates than PCS for different resource market types; and 2) the CMS in this paper achieved higher final utility than the CMS in other works. Additionally, the properties of the three classes of CMSs in

  16. Relative Nonlinear Electrodynamics Interaction of Charged Particles with Strong and Super Strong Laser Fields

    CERN Document Server

    Avetissian, Hamlet

    2006-01-01

    This book covers a large class of fundamental investigations into Relativistic Nonlinear Electrodynamics. It explores the interaction between charged particles and strong laser fields, mainly concentrating on contemporary problems of x-ray lasers, new type small set-up high-energy accelerators of charged particles, as well as electron-positron pair production from super powerful laser fields of relativistic intensities. It will also discuss nonlinear phenomena of threshold nature that eliminate the concurrent inverse processes in the problems of Laser Accelerator and Free Electron Laser, thus creating new opportunities for solving these problems.

  17. Oligopolistic concurrence and investment: application to electricity markets

    International Nuclear Information System (INIS)

    Meunier, G.

    2008-12-01

    This research aims at analysing investment strategies of firms which are in an oligopolistic situation. After a brief description of the physical characteristics of an electric system, the author describes the reforms and defines the problematic of an investment in electricity production within markets in imperfect concurrence. In a first part, the author analyses the heterogeneity (either exogenous or endogenous) and technology choices of oligopolistic firms. In case of an exogenous heterogeneity, he studies the impact of the number of firms on investment decisions. In the second part, the author examines the regulations introduced in industries in imperfect concurrence: electricity production by a public firm and interaction between emission allowance market and investment

  18. Separative power of an optimised concurrent gas centrifuge

    Energy Technology Data Exchange (ETDEWEB)

    Bogovalov, Sergey; Boman, Vladimir [National Research Nuclear University (MEPHI), Moscow (Russian Federation)

    2016-06-15

    The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to δU = 12.7 (V/700 m/s)2(300 K/T)(L/1 m) kg·SWU/yr, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

  19. Concurrent engineering and product models in seafood companies

    DEFF Research Database (Denmark)

    Jonsdottir, Stella; Vesterager, Johan; Børresen, Torger

    1998-01-01

    Concurrent Engineering (CE) can provide an improved approach to product development for extending the lines of seafood products. Information technology (IT) support tools based on product models can provide an integrated and simultaneous approach for specifying new recipes. The seafood industry can...... benefit from the CE approach which can support product developers to provide concurrent specifications for raw materials, ingredients, packaging, and production methods. The approach involves the use of product models from which line extensions are more easily generated than by use of customary stepwise...

  20. Nonlinear robust hierarchical control for nonlinear uncertain systems

    Directory of Open Access Journals (Sweden)

    Leonessa Alexander

    1999-01-01

    Full Text Available A nonlinear robust control-system design framework predicated on a hierarchical switching controller architecture parameterized over a set of moving nominal system equilibria is developed. Specifically, using equilibria-dependent Lyapunov functions, a hierarchical nonlinear robust control strategy is developed that robustly stabilizes a given nonlinear system over a prescribed range of system uncertainty by robustly stabilizing a collection of nonlinear controlled uncertain subsystems. The robust switching nonlinear controller architecture is designed based on a generalized (lower semicontinuous Lyapunov function obtained by minimizing a potential function over a given switching set induced by the parameterized nominal system equilibria. The proposed framework robustly stabilizes a compact positively invariant set of a given nonlinear uncertain dynamical system with structured parametric uncertainty. Finally, the efficacy of the proposed approach is demonstrated on a jet engine propulsion control problem with uncertain pressure-flow map data.

  1. Discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities

    DEFF Research Database (Denmark)

    Khare, A.; Rasmussen, Kim Ø; Salerno, M.

    2006-01-01

    -Ladik equation. As a common property, these equations possess three kinds of exact analytical stationary solutions for which the Peierls-Nabarro barrier is zero. Several properties of these solutions, including stability, discrete breathers, and moving solutions, are investigated.......A class of discrete nonlinear Schrodinger equations with arbitrarily high-order nonlinearities is introduced. These equations are derived from the same Hamiltonian using different Poisson brackets and include as particular cases the saturable discrete nonlinear Schrodinger equation and the Ablowitz...

  2. Non-linear osmosis

    Science.gov (United States)

    Diamond, Jared M.

    1966-01-01

    1. The relation between osmotic gradient and rate of osmotic water flow has been measured in rabbit gall-bladder by a gravimetric procedure and by a rapid method based on streaming potentials. Streaming potentials were directly proportional to gravimetrically measured water fluxes. 2. As in many other tissues, water flow was found to vary with gradient in a markedly non-linear fashion. There was no consistent relation between the water permeability and either the direction or the rate of water flow. 3. Water flow in response to a given gradient decreased at higher osmolarities. The resistance to water flow increased linearly with osmolarity over the range 186-825 m-osM. 4. The resistance to water flow was the same when the gall-bladder separated any two bathing solutions with the same average osmolarity, regardless of the magnitude of the gradient. In other words, the rate of water flow is given by the expression (Om — Os)/[Ro′ + ½k′ (Om + Os)], where Ro′ and k′ are constants and Om and Os are the bathing solution osmolarities. 5. Of the theories advanced to explain non-linear osmosis in other tissues, flow-induced membrane deformations, unstirred layers, asymmetrical series-membrane effects, and non-osmotic effects of solutes could not explain the results. However, experimental measurements of water permeability as a function of osmolarity permitted quantitative reconstruction of the observed water flow—osmotic gradient curves. Hence non-linear osmosis in rabbit gall-bladder is due to a decrease in water permeability with increasing osmolarity. 6. The results suggest that aqueous channels in the cell membrane behave as osmometers, shrinking in concentrated solutions of impermeant molecules and thereby increasing membrane resistance to water flow. A mathematical formulation of such a membrane structure is offered. PMID:5945254

  3. Nonlinear diffusion equations

    CERN Document Server

    Wu Zhuo Qun; Li Hui Lai; Zhao Jun Ning

    2001-01-01

    Nonlinear diffusion equations, an important class of parabolic equations, come from a variety of diffusion phenomena which appear widely in nature. They are suggested as mathematical models of physical problems in many fields, such as filtration, phase transition, biochemistry and dynamics of biological groups. In many cases, the equations possess degeneracy or singularity. The appearance of degeneracy or singularity makes the study more involved and challenging. Many new ideas and methods have been developed to overcome the special difficulties caused by the degeneracy and singularity, which

  4. Methods of nonlinear analysis

    CERN Document Server

    Bellman, Richard Ernest

    1970-01-01

    In this book, we study theoretical and practical aspects of computing methods for mathematical modelling of nonlinear systems. A number of computing techniques are considered, such as methods of operator approximation with any given accuracy; operator interpolation techniques including a non-Lagrange interpolation; methods of system representation subject to constraints associated with concepts of causality, memory and stationarity; methods of system representation with an accuracy that is the best within a given class of models; methods of covariance matrix estimation;methods for low-rank mat

  5. Nonlinear optimal control theory

    CERN Document Server

    Berkovitz, Leonard David

    2012-01-01

    Nonlinear Optimal Control Theory presents a deep, wide-ranging introduction to the mathematical theory of the optimal control of processes governed by ordinary differential equations and certain types of differential equations with memory. Many examples illustrate the mathematical issues that need to be addressed when using optimal control techniques in diverse areas. Drawing on classroom-tested material from Purdue University and North Carolina State University, the book gives a unified account of bounded state problems governed by ordinary, integrodifferential, and delay systems. It also dis

  6. Topics in Nonlinear Dynamics

    DEFF Research Database (Denmark)

    Mosekilde, Erik

    Through a significant number of detailed and realistic examples this book illustrates how the insights gained over the past couple of decades in the fields of nonlinear dynamics and chaos theory can be applied in practice. Aomng the topics considered are microbiological reaction systems, ecological...... food-web systems, nephron pressure and flow regulation, pulsatile secretion of hormones, thermostatically controlled radiator systems, post-stall maneuvering of aircrafts, transfer electron devices for microwave generation, economic long waves, human decision making behavior, and pattern formation...... in chemical reaction-diffusion systems....

  7. Nonlinear dynamics in psychology

    Directory of Open Access Journals (Sweden)

    Stephen J. Guastello

    2001-01-01

    Full Text Available This article provides a survey of the applications of nonlinear dynamical systems theory to substantive problems encountered in the full scope of psychological science. Applications are organized into three topical areas – cognitive science, social and organizational psychology, and personality and clinical psychology. Both theoretical and empirical studies are considered with an emphasis on works that capture the broadest scope of issues that are of substantive interest to psychological theory. A budding literature on the implications of NDS principles in professional practice is reported also.

  8. Nonlinear Hamiltonian systems

    DEFF Research Database (Denmark)

    Jørgensen, Michael Finn

    1995-01-01

    It is generally very difficult to solve nonlinear systems, and such systems often possess chaotic solutions. In the rare event that a system is completely solvable, it is said to integrable. Such systems never have chaotic solutions. Using the Inverse Scattering Transform Method (ISTM) two...... particular configurations of the Discrete Self-Trapping (DST) system are shown to be completely solvable. One of these systems includes the Toda lattice in a certain limit. An explicit integration is carried through for this Near-Toda lattice. The Near-Toda lattice is then generalized to include singular...

  9. Nonlinear surface electromagnetic phenomena

    CERN Document Server

    Ponath, H-E

    1991-01-01

    In recent years the physics of electromagnetic surface phenomena has developed rapidly, evolving into technologies for communications and industry, such as fiber and integrated optics. The variety of phenomena based on electromagnetism at surfaces is rich and this book was written with the aim of summarizing the available knowledge in selected areas of the field. The book contains reviews written by solid state and optical physicists on the nonlinear interaction of electromagnetic waves at and with surfaces and films. Both the physical phenomena and some potential applications are

  10. Oscillators from nonlinear realizations

    Science.gov (United States)

    Kozyrev, N.; Krivonos, S.

    2018-02-01

    We construct the systems of the harmonic and Pais-Uhlenbeck oscillators, which are invariant with respect to arbitrary noncompact Lie algebras. The equations of motion of these systems can be obtained with the help of the formalism of nonlinear realizations. We prove that it is always possible to choose time and the fields within this formalism in such a way that the equations of motion become linear and, therefore, reduce to ones of ordinary harmonic and Pais-Uhlenbeck oscillators. The first-order actions, that produce these equations, can also be provided. As particular examples of this construction, we discuss the so(2, 3) and G 2(2) algebras.

  11. The Concurrent Development of Spelling Skills in Two Languages

    Science.gov (United States)

    Joy, Rhonda

    2011-01-01

    The study reported on in this paper investigated the concurrent development of spelling in children learning two languages. The study compared over time and between languages the types of spelling errors made in English as a first language and French as a second. Fortyseven grade one English-speaking children completed an English and French…

  12. The Relational Concurrence of Global Warming and Economic ...

    African Journals Online (AJOL)

    An attempt has been made to examine the concurrent relationship between global warming and economic development focusing on the danger it inheres in developing countries. To achieve this, the paper commenced with the conceptualization of global warming and economic development, the natural and human causes ...

  13. Transactions on Petri Nets and Other Models of Concurrency VI

    DEFF Research Database (Denmark)

    The sixth volume of ToPNoC includes revised versions of selected papers from workshops and tutorials held at the 32nd International Conference on Application and Theory of Petri Nets and Concurrency. It also contains a special section on Networks, Protocols, and Services, as well as a contributed...

  14. A Symbolic Approach to Permission Accounting for Concurrent Reasoning

    NARCIS (Netherlands)

    Huisman, Marieke; Mostowski, Wojciech

    2015-01-01

    Permission accounting is fundamental to modular, thread-local reasoning about concurrent programs. This paper presents a new, symbolic system for permission accounting. In existing systems, permissions are numeric value-based and refer to the current thread only. Our system is based on symbolic

  15. Concurrent Speech Segregation Problems in Hearing Impaired Children

    Directory of Open Access Journals (Sweden)

    Hossein Talebi

    2014-04-01

    Full Text Available Objective: This study was a basic investigation of the ability of concurrent speech segregation in hearing impaired children. Concurrent segregation is one of the fundamental components of auditory scene analysis and plays an important role in speech perception. In the present study, we compared auditory late responses or ALRs between hearing impaired and normal children. Materials & Methods: Auditory late potentials in response to 12 double vowels were recorded in 10 children with moderate to severe sensory neural hearing loss and 10 normal children. Double vowels (pairs of synthetic vowels were presented concurrently and binaurally. Fundamental frequency (F0 of these vowels and the size of the difference in F0 between vowels was 100 Hz and 0.5 semitones respectively. Results: Comparing N1-P2 amplitude showed statistically significant difference in some stimuli between hearing impaired and normal children (P<0.05. This complex indexing the vowel change detection and reflecting central auditory speech representation without active client participation was decreased in hearing impaired children. Conclusion: This study showed problems in concurrent speech segregation in hearing impaired children evidenced by ALRs. This information indicated deficiencies in bottom-up processing of speech characteristics based on F0 and its differences in these children.

  16. Antisocial Behavior and Depressive Symptoms: Longitudinal and Concurrent Relations

    Science.gov (United States)

    Vieno, Alessio; Kiesner, Jeff; Pastore, Massimiliano; Santinello, Massimo

    2008-01-01

    The relations between antisocial behavior and depressive symptoms were examined both longitudinally and concurrently in a sample of Italian early-adolescents. Structural equation modelling was applied to 10-month longitudinal data from a sample of 107 youths (54 girls; mean age at baseline = M = 12.5). Early adolescents completed a questionnaire…

  17. Mechanical verification of concurrency control and recovery protocols

    NARCIS (Netherlands)

    Chkliaev, D.

    2001-01-01

    The thesis concerns the formal specification and mechanized verification of concurrency control and recovery protocols for distributed databases. Such protocols are needed for many modern application such as banking and are often used in safety-critical applications. Therefore it is very important

  18. Bidirectional Interference between Timing and Concurrent Memory Processing in Children

    Science.gov (United States)

    Rattat, Anne-Claire

    2010-01-01

    This study investigated the nature of resources involved in duration processing in 5- and 8-year-olds. The children were asked to reproduce the duration of a visual or auditory stimulus. They performed this task either alone or concurrently with an executive task (Experiment 1) or with a digit or visuospatial memory task (Experiment 2). The…

  19. Partnership duration, concurrency, and HIV in sub-Saharan Africa.

    Science.gov (United States)

    Sawers, Larry; Isaac, Alan

    2017-07-01

    A widely accepted explanation for the exceptionally high HIV prevalence in sub-Saharan Africa is the practice of long-term overlapping heterosexual partnering. This article shows that long-duration concurrent partnering can be protective against HIV transmission rather than promoting it. Monogamous partnering prevents sexual transmission to anyone outside the partnership and, in an initially concordant-seronegative partnership, prevents sexual acquisition of HIV by either partner. Those protections against transmission and acquisition last as long as the partnership persists without new outside partnerships. Correspondingly, these two protective effects characterise polygynous partnerships, whether or not the polygyny is formal or informal, until a partner initiates a new partnership. Stable and exclusive unions of any size protect against HIV transmission, and more durable unions provide a longer protective effect. Survey research provides little information on partnership duration in sub-Saharan Africa and sheds no light on the interaction of duration, concurrency, and HIV. This article shows how assumptions about partnership duration in individual-based sexual-network models affect the contours of simulated HIV epidemics. Longer mean partnership duration slows the pace at which simulated epidemics grow. With plausible assumptions about partnership duration and at levels of concurrency found in the region, simulated HIV epidemics grow slowly or not at all. Those results are consistent with the hypothesis that long-duration partnering is protective against HIV and inconsistent with the hypothesis that long-term concurrency drives the HIV epidemics in sub-Saharan Africa.

  20. La Concurrence et le développement

    International Development Research Centre (IDRC) Digital Library (Canada)

    Depuis 2002, le CRDI finance des recherches sur la politique de la concurrence .... Recruter un personnel expert et bien le rémunérer — Les nouvelles autorités ...... propriété par un plus grand nombre de Sud-Africains un objectif stratégique.

  1. Concurrent control system for the JAERI tandem accelerator

    International Nuclear Information System (INIS)

    Hanashima, S.; Shoji, T.; Horie, K.; Tsukihashi, Y.

    1992-01-01

    Concurrent processing with a multiprocessor system is introduced to the particle accelerator control system region. The control system is a good application in both logical and physical aspects. A renewal plan of the control system for the JAERI tandem accelerator is discussed. (author)

  2. Critical points based register-concurrency autotuning for GPUs

    NARCIS (Netherlands)

    Li, A.; Song, S.L.; Kumar, A.; Zhang, E.Z.; Chavarría-Miranda, D.; Corporaal, H.

    2016-01-01

    The unprecedented prevalence of GPGPU is largely attributed to its abundant on-chip register resources, which allow massively concurrent threads and extremely fast context switch. However, due to internal memory size constraints, there is a tradeoff between the per-thread register usage and the

  3. Concurrent Learning of Control in Multi agent Sequential Decision Tasks

    Science.gov (United States)

    2018-04-17

    Concurrent Learning of Control in Multi-agent Sequential Decision Tasks The overall objective of this project was to develop multi-agent reinforcement... learning (MARL) approaches for intelligent agents to autonomously learn distributed control policies in decentral- ized partially observable... learning of policies in Dec-POMDPs, established performance bounds, evaluated these algorithms both theoretically and empirically, The views

  4. 14 CFR 221.140 - Method of giving concurrence.

    Science.gov (United States)

    2010-01-01

    ...) Conflicting authority to be avoided. Care should be taken to avoid giving authority to two or more carriers... Aviation shall be used by a carrier to give authority to another carrier to issue and file with the... used as authority to file joint fares or charges in which the carrier to whom the concurrence is given...

  5. Selective Impairment of Auditory Selective Attention under Concurrent Cognitive Load

    Science.gov (United States)

    Dittrich, Kerstin; Stahl, Christoph

    2012-01-01

    Load theory predicts that concurrent cognitive load impairs selective attention. For visual stimuli, it has been shown that this impairment can be selective: Distraction was specifically increased when the stimulus material used in the cognitive load task matches that of the selective attention task. Here, we report four experiments that…

  6. Towards PCC for Concurrent and Distributed Systems (Work in Progress)

    Science.gov (United States)

    Henriksen, Anders S.; Filinski, Andrzej

    2009-01-01

    We outline some conceptual challenges in extending the PCC paradigm to a concurrent and distributed setting, and sketch a generalized notion of module correctness based on viewing communication contracts as economic games. The model supports compositional reasoning about modular systems and is meant to apply not only to certification of executable code, but also of organizational workflows.

  7. Sexual networks and social capital: multiple and concurrent sexual ...

    African Journals Online (AJOL)

    Multiple and concurrent sexual partnerships (MCP) are prevalent in southern Africa and have been identified as a primary cause of high HIV prevalence in this region. Sexual liaisons with multiple partners serve to increase the size and diversity of an individual's sexual — and social — network and therefore to increase their ...

  8. The Influence of Concurrent Ascaridia and Heterakis Infections of ...

    African Journals Online (AJOL)

    Blood samples from the same fowls were also collected and analyzed for PCV (%), RBC, Hb and differential white cell count using established standard procedures. Results from the study reveal a concurrent prevalence of 45.5%. Respective prevalence was in the order Ascaridia numida 56.05% and Heterakis gallinarum ...

  9. Context-Based Synchronization of Concurrent Process Using Aspect ...

    African Journals Online (AJOL)

    ... will not cause any race condition if all other threads are accessing from the same context. The result of our experiment shows that context-based synchronization performs better than Java given the same number of threads. Keywords: Aspect-oriented programming, synchronization, resource, and concurrent process.

  10. Threaded Cognition: An Integrated Theory of Concurrent Multitasking

    Science.gov (United States)

    Salvucci, Dario D.; Taatgen, Niels A.

    2008-01-01

    The authors propose the idea of threaded cognition, an integrated theory of concurrent multitasking--that is, performing 2 or more tasks at once. Threaded cognition posits that streams of thought can be represented as threads of processing coordinated by a serial procedural resource and executed across other available resources (e.g., perceptual…

  11. Threaded cognition : An integrated theory of concurrent multitasking

    NARCIS (Netherlands)

    Salvucci, Dario D.; Taatgen, Niels A.

    The authors propose the idea of threaded cognition, an integrated theory of concurrent multitasking-that is, performing 2 or more tasks at once. Threaded cognition posits that streams of thought can be represented as threads of processing coordinated by a serial procedural resource and executed

  12. Responses of rabbits to concurrent administration of Furosemide ...

    African Journals Online (AJOL)

    The intramuscular (IM) administrations of 5 mg/kg xylazine, followed 30 min later by IM of 35 mg/kg ketamine alone (XK) or concurrently with IM of 1 mg/kg furosemide (XKF), were assessed in six healthy rabbits (4 bucks and 2 does) using selected anaesthetic indices (time to onset of anaesthesia, time to onset of analgesia, ...

  13. The risks of concurrent treatment with tenofovir and aminoglycosides ...

    African Journals Online (AJOL)

    The risks of concurrent treatment with tenofovir and aminoglycosides in patients with HIV-associated tuberculosis. C Kenyon, N Wearne, R Burton, G Meintjes. Abstract. The South African public sector antiretroviral treatment (ART) guidelines have recently been changed to include tenofovir in the first-line regimen.1 ...

  14. Concurrent signal combining and channel estimation in digital communications

    Science.gov (United States)

    Ormesher, Richard C [Albuquerque, NM; Mason, John J [Albuquerque, NM

    2011-08-30

    In the reception of digital information transmitted on a communication channel, a characteristic exhibited by the communication channel during transmission of the digital information is estimated based on a communication signal that represents the digital information and has been received via the communication channel. Concurrently with the estimating, the communication signal is used to decide what digital information was transmitted.

  15. Risk factors for concurrent bacteremia in adult patients with dengue

    Directory of Open Access Journals (Sweden)

    Tun-Linn Thein

    2017-06-01

    Conclusion: Concurrent bacteremia in adult patients with dengue is uncommon but presents atypically and results in more deaths and longer hospital stay. Given the associated mortality, collection of blood cultures and empiric antibiotic therapy may be considered in patients who are critically ill.

  16. A Patient Presenting with Concurrent Testis Torsion and Epididymal Leiomyoma

    Directory of Open Access Journals (Sweden)

    E. Arpali

    2013-01-01

    Full Text Available Leiomyomas are the second most common tumors of epididymis. Patients with leiomyomas are sometimes misdiagnosed with testicular tumors. A Case of a patient with a scrotal mass presenting with testicular torsion is reported. Concurrent occurrence of testicular torsion and epididymal leiomyoma is an extremely rare condition.

  17. Determinants of overweight with concurrent stunting among Ghanaian children.

    Science.gov (United States)

    Atsu, Benedicta K; Guure, Chris; Laar, Amos K

    2017-07-27

    Malnutrition (undernutrition and overnutrition) is a major public health problem in Ghana -affecting growth and development of individuals and the nation. Stunting and overweight are of particular interest, as recent national surveys show a rising trend of overnutrition and stubbornly high burden of stunting among Ghanaian children. There are currently no data on the simultaneous occurrence of overweight and stunting within individuals in Ghana. This paper presents the burden, the individual-level, and contextual determinants of overweight with concurrent stunting among Ghanaian children. This study analyzed data set of the fourth round of the Ghana Multiple Indicator Cluster Survey (MICS4). Bivariate analyses were used to describe selected characteristics of survey respondents and their children. Hierarchical modelling approach facilitated identification of significant distal, intermediate and proximal factors/determinants of concurrent stunting and overweight. Both crude and adjusted prevalence ratios via a multivariable Poison regression model with their corresponding 95% Confidence Intervals (CI) are reported. Variables with p ≤ 0.25 at the bivariate level were included in the multivariable analysis. An alpha value of 5% was used to indicate significance. Of 7550 cases (children) analyzed, the prevalence of stunting was 27.5%; underweight was 17.3%; and wasting was 7.7%. The prevalence of overweight and concurrent overweight and stunting were respectively 2.4% and 1.2%. Children who belonged to the fourth wealth quintile, were more likely to be overweight and concurrently stunted as against children belonging to the poorest quintile (aPR = 1.010; 95% CI, 1.003-1.017). Compared to religious (Christians/Muslim/Traditionalist) household heads, children whose household heads did not belong to any religion had 2 times the rates of the Overweight with concurrent stunting (PR = 2.024; 95% CI, 1.016-4.034). Children with mothers aged 20-34 and 35-49 had an

  18. Global Analysis of Nonlinear Dynamics

    CERN Document Server

    Luo, Albert

    2012-01-01

    Global Analysis of Nonlinear Dynamics collects chapters on recent developments in global analysis of non-linear dynamical systems with a particular emphasis on cell mapping methods developed by Professor C.S. Hsu of the University of California, Berkeley. This collection of contributions prepared by a diverse group of internationally recognized researchers is intended to stimulate interests in global analysis of complex and high-dimensional nonlinear dynamical systems, whose global properties are largely unexplored at this time. This book also: Presents recent developments in global analysis of non-linear dynamical systems Provides in-depth considerations and extensions of cell mapping methods Adopts an inclusive style accessible to non-specialists and graduate students Global Analysis of Nonlinear Dynamics is an ideal reference for the community of nonlinear dynamics in different disciplines including engineering, applied mathematics, meteorology, life science, computational science, and medicine.  

  19. Nonlinearity management in higher dimensions

    International Nuclear Information System (INIS)

    Kevrekidis, P G; Pelinovsky, D E; Stefanov, A

    2006-01-01

    In the present paper, we revisit nonlinearity management of the time-periodic nonlinear Schroedinger equation and the related averaging procedure. By means of rigorous estimates, we show that the averaged nonlinear Schroedinger equation does not blow up in the higher dimensional case so long as the corresponding solution remains smooth. In particular, we show that the H 1 norm remains bounded, in contrast with the usual blow-up mechanism for the focusing Schroedinger equation. This conclusion agrees with earlier works in the case of strong nonlinearity management but contradicts those in the case of weak nonlinearity management. The apparent discrepancy is explained by the divergence of the averaging procedure in the limit of weak nonlinearity management

  20. Collapse of nonlinear Langmuir waves

    International Nuclear Information System (INIS)

    Malkin, V.M.

    1986-01-01

    The dispersion of sufficiently intensive Langmuir waves is determined by intrinsic (electron) nonlinearity. During Langmuir collapse the wave energy density required for the appearance of electron nonlinearity is attained, generally speaking, prior to the development of dissipative processes. Up to now, the effect of electron nonlinearity on the collapse dynamics and spectrum of strong Langmuir turbulence ( which may be very appreciable ) has not been studied extensively because of the difficulty of describing nonlinear Langmuir waves. In the present paper the positive determinacy of the electron nonlinear hamiltonian is proven, the increment of modulation instability of a nonlinear Langmuir wave cluster localized in a cavity is calculated, and the universal law of their collapse is found

  1. Applications of nonlinear fiber optics

    CERN Document Server

    Agrawal, Govind

    2008-01-01

    * The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The bo

  2. Recent topics in nonlinear PDE

    International Nuclear Information System (INIS)

    Mimura, Masayasu; Nishida, Takaaki

    1984-01-01

    The meeting on the subject of nonlinear partial differential equations was held at Hiroshima University in February, 1983. Leading and active mathematicians were invited to talk on their current research interests in nonlinear pdes occuring in the areas of fluid dynamics, free boundary problems, population dynamics and mathematical physics. This volume contains the theory of nonlinear pdes and the related topics which have been recently developed in Japan. (Auth.)

  3. Perspectives of nonlinear dynamics

    International Nuclear Information System (INIS)

    Jackson, E.A.

    1985-03-01

    Four lectures were given weekly in October and November, 1984, and some of the ideas presented here will be of use in the future. First, a brief survey of the historical development of nonlinear dynamics since about 1890 was given, and then, a few topics were discussed in detail. The objective was to introduce some of many concepts and methods which are presently used for describing nonlinear dynamics. The symbiotic relationship between sciences of all types and mathematics, two main categories of the models describing nature, the method for describing the dynamics of a system, the idea of control parameters and topological dimension, the asymptotic properties of dynamics, abstract dynamics, the concept of embedding, singular perturbation theory, strange attractor, Fermi-Pasta-Ulam phenomena, an example of computer heuristics, the idea of elementary catastrophe theory and so on were explained. The logistic map is the simplest introduction to complex dynamics. The complicated dynamics is referred to as strange attractors. Two-dimensional maps are the highest dimensional maps commonly studied. These were discussed in detail. (Kako, I.)

  4. Nonlinearities in Behavioral Macroeconomics.

    Science.gov (United States)

    Gomes, Orlando

    2017-07-01

    This article undertakes a journey across the literature on behavioral macroeconomics, with attention concentrated on the nonlinearities that the behavioral approach typically suggests or implies. The emphasis is placed on thinking the macro economy as a living organism, composed of many interacting parts, each one having a will of its own, which is in sharp contrast with the mechanism of the orthodox view (well represented by the neoclassical or new Keynesian dynamic stochastic general equilibrium - DSGE - model). The paper advocates that a thorough understanding of individual behavior in collective contexts is the only possible avenue to further explore macroeconomic phenomena and the often observed 'anomalies' that the benchmark DSGE macro framework is unable to explain or justify. After a reflection on the role of behavioral traits as a fundamental component of a new way of thinking the economy, the article proceeds with a debate on some of the most relevant frameworks in the literature that somehow link macro behavior and nonlinearities; covered subjects include macro models with disequilibrium rules, agent-based models that highlight interaction and complexity, evolutionary switching frameworks, and inattention based decision problems. These subjects have, as a fundamental point in common, the use of behavioral elements to transform existing interpretations of the economic reality, making it more evident how irregular fluctuations emerge and unfold on the aggregate.

  5. Nonlinear Waves in Complex Systems

    DEFF Research Database (Denmark)

    2007-01-01

    The study of nonlinear waves has exploded due to the combination of analysis and computations, since the discovery of the famous recurrence phenomenon on a chain of nonlinearly coupled oscillators by Fermi-Pasta-Ulam fifty years ago. More than the discovery of new integrable equations, it is the ......The study of nonlinear waves has exploded due to the combination of analysis and computations, since the discovery of the famous recurrence phenomenon on a chain of nonlinearly coupled oscillators by Fermi-Pasta-Ulam fifty years ago. More than the discovery of new integrable equations...

  6. Problems in nonlinear resistive MHD

    International Nuclear Information System (INIS)

    Turnbull, A.D.; Strait, E.J.; La Haye, R.J.; Chu, M.S.; Miller, R.L.

    1998-01-01

    Two experimentally relevant problems can relatively easily be tackled by nonlinear MHD codes. Both problems require plasma rotation in addition to the nonlinear mode coupling and full geometry already incorporated into the codes, but no additional physics seems to be crucial. These problems discussed here are: (1) nonlinear coupling and interaction of multiple MHD modes near the B limit and (2) nonlinear coupling of the m/n = 1/1 sawtooth mode with higher n gongs and development of seed islands outside q = 1

  7. Nonlinear Response of Strong Nonlinear System Arisen in Polymer Cushion

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2013-01-01

    Full Text Available A dynamic model is proposed for a polymer foam-based nonlinear cushioning system. An accurate analytical solution for the nonlinear free vibration of the system is derived by applying He's variational iteration method, and conditions for resonance are obtained, which should be avoided in the cushioning design.

  8. Nonlinear Preconditioning and its Application in Multicomponent Problems

    KAUST Repository

    Liu, Lulu

    2015-12-07

    The Multiplicative Schwarz Preconditioned Inexact Newton (MSPIN) algorithm is presented as a complement to Additive Schwarz Preconditioned Inexact Newton (ASPIN). At an algebraic level, ASPIN and MSPIN are variants of the same strategy to improve the convergence of systems with unbalanced nonlinearities; however, they have natural complementarity in practice. MSPIN is naturally based on partitioning of degrees of freedom in a nonlinear PDE system by field type rather than by subdomain, where a modest factor of concurrency can be sacrificed for physically motivated convergence robustness. ASPIN, originally introduced for decompositions into subdomains, is natural for high concurrency and reduction of global synchronization. The ASPIN framework, as an option for the outermost solver, successfully handles strong nonlinearities in computational fluid dynamics, but is barely explored for the highly nonlinear models of complex multiphase flow with capillarity, heterogeneity, and complex geometry. In this dissertation, the fully implicit ASPIN method is demonstrated for a finite volume discretization based on incompressible two-phase reservoir simulators in the presence of capillary forces and gravity. Numerical experiments show that the number of global nonlinear iterations is not only scalable with respect to the number of processors, but also significantly reduced compared with the standard inexact Newton method with a backtracking technique. Moreover, the ASPIN method, in contrast with the IMPES method, saves overall execution time because of the savings in timestep size. We consider the additive and multiplicative types of inexact Newton algorithms in the field-split context, and we augment the classical convergence theory of ASPIN for the multiplicative case. Moreover, we provide the convergence analysis of the MSPIN algorithm. Under suitable assumptions, it is shown that MSPIN is locally convergent, and desired superlinear or even quadratic convergence can be

  9. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-01

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  10. Nonlinear Photonic Crystal Fibers

    DEFF Research Database (Denmark)

    Hansen, Kim Per

    2004-01-01

    Despite the general recession in the global economy and the collapse of the optical telecommunication market, research within specialty fibers is thriving. This is, more than anything else, due to the technology transition from standard all-glass fibers to photonic crystal fibers, which, instead....... The freedom to design the dispersion profile of the fibers is much larger and it is possible to create fibers, which support only a single spatial mode, regardless of wavelength. In comparison, the standard dispersion-shifted fibers are limited by a much lower index-contrast between the core and the cladding...... in 1996, and are today on their way to become the dominating technology within the specialty fiber field. Whether they will replace the standard fiber in the more traditional areas like telecommunication transmission, is not yet clear, but the nonlinear photonic crystal fibers are here to stay....

  11. Nonlinear estimation and classification

    CERN Document Server

    Hansen, Mark; Holmes, Christopher; Mallick, Bani; Yu, Bin

    2003-01-01

    Researchers in many disciplines face the formidable task of analyzing massive amounts of high-dimensional and highly-structured data This is due in part to recent advances in data collection and computing technologies As a result, fundamental statistical research is being undertaken in a variety of different fields Driven by the complexity of these new problems, and fueled by the explosion of available computer power, highly adaptive, non-linear procedures are now essential components of modern "data analysis," a term that we liberally interpret to include speech and pattern recognition, classification, data compression and signal processing The development of new, flexible methods combines advances from many sources, including approximation theory, numerical analysis, machine learning, signal processing and statistics The proposed workshop intends to bring together eminent experts from these fields in order to exchange ideas and forge directions for the future

  12. Nonlinear Water Waves

    CERN Document Server

    2016-01-01

    This volume brings together four lecture courses on modern aspects of water waves. The intention, through the lectures, is to present quite a range of mathematical ideas, primarily to show what is possible and what, currently, is of particular interest. Water waves of large amplitude can only be fully understood in terms of nonlinear effects, linear theory being not adequate for their description. Taking advantage of insights from physical observation, experimental evidence and numerical simulations, classical and modern mathematical approaches can be used to gain insight into their dynamics. The book presents several avenues and offers a wide range of material of current interest. Due to the interdisciplinary nature of the subject, the book should be of interest to mathematicians (pure and applied), physicists and engineers. The lectures provide a useful source for those who want to begin to investigate how mathematics can be used to improve our understanding of water wave phenomena. In addition, some of the...

  13. Perspectives on Nonlinear Filtering

    KAUST Repository

    Law, Kody

    2015-01-07

    The solution to the problem of nonlinear filtering may be given either as an estimate of the signal (and ideally some measure of concentration), or as a full posterior distribution. Similarly, one may evaluate the fidelity of the filter either by its ability to track the signal or its proximity to the posterior filtering distribution. Hence, the field enjoys a lively symbiosis between probability and control theory, and there are plenty of applications which benefit from algorithmic advances, from signal processing, to econometrics, to large-scale ocean, atmosphere, and climate modeling. This talk will survey some recent theoretical results involving accurate signal tracking with noise-free (degenerate) dynamics in high-dimensions (infinite, in principle, but say d between 103 and 108 , depending on the size of your application and your computer), and high-fidelity approximations of the filtering distribution in low dimensions (say d between 1 and several 10s).

  14. Wave transmission in nonlinear lattices

    International Nuclear Information System (INIS)

    Hennig, D.; Tsironis, G.P.

    1999-01-01

    The interplay of nonlinearity with lattice discreteness leads to phenomena and propagation properties quite distinct from those appearing in continuous nonlinear systems. For a large variety of condensed matter and optics applications the continuous wave approximation is not appropriate. In the present review we discuss wave transmission properties in one dimensional nonlinear lattices. Our paradigmatic equations are discrete nonlinear Schroedinger equations and their study is done through a dynamical systems approach. We focus on stationary wave properties and utilize well known results from the theory of dynamical systems to investigate various aspects of wave transmission and wave localization. We analyze in detail the more general dynamical system corresponding to the equation that interpolates between the non-integrable discrete nonlinear Schroedinger equation and the integrable Albowitz-Ladik equation. We utilize this analysis in a nonlinear Kronig-Penney model and investigate transmission and band modification properties. We discuss the modifications that are effected through an electric field and the nonlinear Wannier-Stark localization effects that are induced. Several applications are described, such as polarons in one dimensional lattices, semiconductor superlattices and one dimensional nonlinear photonic band gap systems. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. Solving Nonlinear Coupled Differential Equations

    Science.gov (United States)

    Mitchell, L.; David, J.

    1986-01-01

    Harmonic balance method developed to obtain approximate steady-state solutions for nonlinear coupled ordinary differential equations. Method usable with transfer matrices commonly used to analyze shaft systems. Solution to nonlinear equation, with periodic forcing function represented as sum of series similar to Fourier series but with form of terms suggested by equation itself.

  16. Nonlinear Elasticity of Doped Semiconductors

    Science.gov (United States)

    2017-02-01

    AFRL-RY-WP-TR-2016-0206 NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS Mark Dykman and Kirill Moskovtsev Michigan State University...2016 4. TITLE AND SUBTITLE NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS 5a. CONTRACT NUMBER FA8650-16-1-7600 5b. GRANT NUMBER 5c. PROGRAM...vibration amplitude. 15. SUBJECT TERMS semiconductors , microresonators, microelectromechanical 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  17. Nonlinear evolution of MHD instabilities

    International Nuclear Information System (INIS)

    Bateman, G.; Hicks, H.R.; Wooten, J.W.; Dory, R.A.

    1975-01-01

    A 3-D nonlinear MHD computer code was used to study the time evolution of internal instabilities. Velocity vortex cells are observed to persist into the nonlinear evolution. Pressure and density profiles convect around these cells for a weak localized instability, or convect into the wall for a strong instability. (U.S.)

  18. Nonlinear theory of elastic shells

    International Nuclear Information System (INIS)

    Costa Junior, J.A.

    1979-08-01

    Nonlinear theory of elastic shells is developed which incorporates both geometric and physical nonlinearities and which does not make use of the well known Love-Kirchhoff hypothesis. The resulting equations are formulated in tensorial notation and are reduced to the ones of common use when simplifying assumptions encountered in the especific litterature are taken. (Author) [pt

  19. Balancing for Unstable Nonlinear Systems

    NARCIS (Netherlands)

    Scherpen, J.M.A.

    1993-01-01

    A previously obtained method of balancing for stable nonlinear systems is extended to unstable nonlinear systems. The similarity invariants obtained by the concept of LQG balancing for an unstable linear system can also be obtained by considering a past and future energy function of the system. By

  20. Optimal analytic method for the nonlinear Hasegawa-Mima equation

    Science.gov (United States)

    Baxter, Mathew; Van Gorder, Robert A.; Vajravelu, Kuppalapalle

    2014-05-01

    The Hasegawa-Mima equation is a nonlinear partial differential equation that describes the electric potential due to a drift wave in a plasma. In the present paper, we apply the method of homotopy analysis to a slightly more general Hasegawa-Mima equation, which accounts for hyper-viscous damping or viscous dissipation. First, we outline the method for the general initial/boundary value problem over a compact rectangular spatial domain. We use a two-stage method, where both the convergence control parameter and the auxiliary linear operator are optimally selected to minimize the residual error due to the approximation. To do the latter, we consider a family of operators parameterized by a constant which gives the decay rate of the solutions. After outlining the general method, we consider a number of concrete examples in order to demonstrate the utility of this approach. The results enable us to study properties of the initial/boundary value problem for the generalized Hasegawa-Mima equation. In several cases considered, we are able to obtain solutions with extremely small residual errors after relatively few iterations are computed (residual errors on the order of 10-15 are found in multiple cases after only three iterations). The results demonstrate that selecting a parameterized auxiliary linear operator can be extremely useful for minimizing residual errors when used concurrently with the optimal homotopy analysis method, suggesting that this approach can prove useful for a number of nonlinear partial differential equations arising in physics and nonlinear mechanics.

  1. Learning from Mistakes --- A Comprehensive Study on Real World Concurrency Bug Characteristics

    International Nuclear Information System (INIS)

    Shan Lu; Soyeon Park; Eunsoo Seo; Yuanyuan Zhou

    2008-01-01

    The reality of multi-core hardware has made concurrent programs pervasive. Unfortunately, writing correct concurrent programs is difficult. Addressing this challenge requires advances in multiple directions, including concurrency bug detection, concurrent program testing, concurrent programming model design, etc. Designing effective techniques in all these directions will significantly benefit from a deep understanding of real world concurrency bug characteristics. This paper provides the first (to the best of our knowledge) comprehensive real world concurrency bug characteristic study. Specifically, we have carefully examined concurrency bug patterns, manifestation, and fix strategies of 105 randomly selected real world concurrency bugs from 4 representative server and client opensource applications (MySQL, Apache, Mozilla and OpenOffice). Our study reveals several interesting findings and provides useful guidance for concurrency bug detection, testing, and concurrent programming language design. Some of our findings are as follows: (1) Around one third of the examined non-deadlock concurrency bugs are caused by violation to programmers order intentions, which may not be easily expressed via synchronization primitives like locks and transactional memories; (2) Around 34% of the examined non-deadlock concurrency bugs involve multiple variables, which are not well addressed by existing bug detection tools; (3) About 92% of the examined concurrency bugs can be reliably triggered by enforcing certain orders among no more than 4 memory accesses. This indicates that testing concurrent programs can target at exploring possible orders among every small groups of memory accesses, instead of among all memory accesses; (4) About 73% of the examined non-deadlock concurrency bugs were not fixed by simply adding or changing locks, and many of the fixes were not correct at the first try, indicating the difficulty of reasoning concurrent execution by programmers.

  2. Criteria for inhalation exposure systems utilizing concurrent flow spirometry

    International Nuclear Information System (INIS)

    Raabe, O.G.; Yeh, H.C.

    1974-01-01

    Principles are given for the design and operation of a new class of inhalation exposure systems utilizing concurrent flow spirometry (CFS), a simple method for providing realtime measurement of respiratory volumes and rates during inhalation exposure by mouth or nose of individual experimental animals or man to aerosols or gases. This technique is especially useful for inhalation exposure of larger experimental animals, such as horses, where whole-body plethysmography is usually impractical. Difficulties encountered with conventional exposure systems in maintenance of uniform aerosol or gas concentrations and prevention of large pressure excursions in the exposure chamber during breathing are obviated by systems utilizing the principles of concurrent flow spirometry. For illustration, two exposure units with CFS are described, one for exposure of Beagle dogs and one for ponies. (U.S.)

  3. Triangle inequalities in coherence measures and entanglement concurrence

    Science.gov (United States)

    Dai, Yue; You, Wenlong; Dong, Yuli; Zhang, Chengjie

    2017-12-01

    We provide detailed proofs of triangle inequalities in coherence measures and entanglement concurrence. If a rank-2 state ϱ can be expressed as a convex combination of two pure states, i.e., ϱ =p1| ψ1〉〈 ψ1|+ p2| ψ2〉〈 ψ2| , a triangle inequality can be established as |E (|Ψ1〉 )-E (|Ψ2〉 )|≤E (ϱ ) ≤E (|Ψ1〉 )+E (|Ψ2〉 ) , where | Ψ1〉= √{p1}|ψ1〉 and | Ψ2〉= √{p2}|ψ2〉 ; E can be considered either coherence measures or entanglement concurrence. This inequality displays mathematical beauty for its similarity to the triangle inequality in plane geometry. An illustrative example is given after the proof.

  4. Concurrent periosteal chondroma and enchondroma of the fibula mimicking chondrosarcoma

    International Nuclear Information System (INIS)

    Yamamoto, Yasuhiro; Washimi, Osuke; Yamada, Harumoto; Washimi, Yuki; Itoh, Masato; Kuroda, Makoto

    2006-01-01

    We present a rare concurrence of enchondroma and periosteal chondroma in the right distal fibula that mimicked chondrosarcoma in a 13-year-old boy. Radiographs and CT scans showed a periosteal lesion producing saucerization without periosteal reaction and calcification in the distal metaphysis of the right fibula. MRI showed an intramedullary lesion adjacent to the periosteal lesion, although it was invisible at CT. There was no cortical breach on imaging and gross examination. Because both lesions represented benign cartilaginous tumors on histology, concurrent periosteal chondroma and enchondroma of the fibula was diagnosed. This combination in the same bone in a patient without enchondromatosis is exceedingly rare. Such imaging features may be confused with those of chondrosarcoma. (orig.)

  5. Concurrent periosteal chondroma and enchondroma of the fibula mimicking chondrosarcoma

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yasuhiro; Washimi, Osuke; Yamada, Harumoto; Washimi, Yuki; Itoh, Masato [Fujita Health University, Department of Orthopedic Surgery, Toyoake City, Aichi (Japan); Kuroda, Makoto [Fujita Health University, Department of Pathology, Toyoake City, Aichi (Japan)

    2006-05-15

    We present a rare concurrence of enchondroma and periosteal chondroma in the right distal fibula that mimicked chondrosarcoma in a 13-year-old boy. Radiographs and CT scans showed a periosteal lesion producing saucerization without periosteal reaction and calcification in the distal metaphysis of the right fibula. MRI showed an intramedullary lesion adjacent to the periosteal lesion, although it was invisible at CT. There was no cortical breach on imaging and gross examination. Because both lesions represented benign cartilaginous tumors on histology, concurrent periosteal chondroma and enchondroma of the fibula was diagnosed. This combination in the same bone in a patient without enchondromatosis is exceedingly rare. Such imaging features may be confused with those of chondrosarcoma. (orig.)

  6. Concurrent Use of Cannabis and Alcohol: Neuropsychiatric Effect Consequences.

    Science.gov (United States)

    Romaguera, Anna; Torrens, Marta; Papaseit, Esther; Arellano, Ana Lucia; Farré, Magi

    2017-01-01

    Concurrent use of cannabis and alcohol is frequent. According different studies, the prevalence is among 20-34% depending on different samples studied. In contrast with the wide evidence available about neuropsychiatric effects associated to the use of cannabis or alcohol separately, there are few studies of the neuropsychiatric effects of their combination. Our aim was to review the literature regarding this topic. We performed a search in MEDLINE and from 114 potentially eligible studies, 27 were selected. Most of them studied the relation between cannabis and alcohol, and with them combined to other substances of abuse, but only a few considered their concurrent effect among mental disorders (ADHD, bipolar disorder) and neuropsychological performance. More research in the neuropsychiatric effects of the concomitant use of cannabis and alcohol is needed. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Winning Concurrent Reachability Games Requires Doubly-Exponential Patience

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Koucký, Michal; Miltersen, Peter Bro

    2009-01-01

    We exhibit a deterministic concurrent reachability game PURGATORYn with n non-terminal positions and a binary choice for both players in every position so that any positional strategy for Player 1 achieving the value of the game within given isin ... that are less than (isin2/(1 - isin))2n-2 . Also, even to achieve the value within say 1 - 2-n/2, doubly exponentially small behavior probabilities in the number of positions must be used. This behavior is close to worst case: We show that for any such game and 0 ... with all non-zero behavior probabilities being 20(n) at least isin2O(n). As a corollary to our results, we conclude that any (deterministic or nondeterministic) algorithm that given a concurrent reachability game explicitly manipulates isin-optimal strategies for Player 1 represented in several standard...

  8. Monomial strategies for concurrent reachability games and other stochastic games

    DEFF Research Database (Denmark)

    Frederiksen, Søren Kristoffer Stiil; Miltersen, Peter Bro

    2013-01-01

    We consider two-player zero-sum finite (but infinite-horizon) stochastic games with limiting average payoffs. We define a family of stationary strategies for Player I parameterized by ε > 0 to be monomial, if for each state k and each action j of Player I in state k except possibly one action, we...... have that the probability of playing j in k is given by an expression of the form c ε d for some non-negative real number c and some non-negative integer d. We show that for all games, there is a monomial family of stationary strategies that are ε-optimal among stationary strategies. A corollary...... is that all concurrent reachability games have a monomial family of ε-optimal strategies. This generalizes a classical result of de Alfaro, Henzinger and Kupferman who showed that this is the case for concurrent reachability games where all states have value 0 or 1....

  9. An Intensional Concurrent Faithful Encoding of Turing Machines

    Directory of Open Access Journals (Sweden)

    Thomas Given-Wilson

    2014-10-01

    Full Text Available The benchmark for computation is typically given as Turing computability; the ability for a computation to be performed by a Turing Machine. Many languages exploit (indirect encodings of Turing Machines to demonstrate their ability to support arbitrary computation. However, these encodings are usually by simulating the entire Turing Machine within the language, or by encoding a language that does an encoding or simulation itself. This second category is typical for process calculi that show an encoding of lambda-calculus (often with restrictions that in turn simulates a Turing Machine. Such approaches lead to indirect encodings of Turing Machines that are complex, unclear, and only weakly equivalent after computation. This paper presents an approach to encoding Turing Machines into intensional process calculi that is faithful, reduction preserving, and structurally equivalent. The encoding is demonstrated in a simple asymmetric concurrent pattern calculus before generalised to simplify infinite terms, and to show encodings into Concurrent Pattern Calculus and Psi Calculi.

  10. A familial concurrence of schizophrenia and Gaucher's disease

    Directory of Open Access Journals (Sweden)

    Siomos Konstantinos E

    2007-12-01

    Full Text Available Abstract Background Gaucher's disease (GD is the most frequently encountered lysosomal storage disease. Here, we describe and discuss the observed concurrence of schizophrenia and Gaucher's disease in two siblings. Methods Presentation of a family with two siblings with Gaucher's disease. Results In a six-member family, the first son suffers from schizophrenia, while the third and fourth sons suffer from the Gaucher's disease (type 1 non-neuronopathic. The parents and the second son do not suffer from either illness. Conclusion The concurrence of schizophrenia and Gaucher's disease in the same family is an unusual phenomenon. The literature regarding this coincidence is limited, despite the fact that patients with Gaucher's disease have one or two mutated alleles, considered to be a risk factor leading to conditions such as Dementia, Parkinson's disease and schizophrenia.

  11. Association between concurrent alcohol and tobacco use and poverty.

    Science.gov (United States)

    de Silva, Varuni; Samarasinghe, Diyanath; Hanwella, Raveen

    2011-01-01

    The harm from alcohol and tobacco use in low- and middle-income countries includes substantial economic cost to the individual. Our aim was to describe the expenditure on concurrent alcohol and tobacco use in relation to family income in two districts in Sri Lanka. A community-based cross-sectional study was carried out in two districts in Sri Lanka. We sampled 2684 men over 18 years of age using multistage cluster sampling. Cost of alcohol and cigarettes was calculated using the retail price for each brand and multiplying by the amount consumed. Among current alcohol users 63.1% were also smokers. Among current smokers 61.9% were also using alcohol. Prevalence of concurrent alcohol and tobacco use in urban areas was 20.1% and in rural areas 14%. The two lowest income categories (meaning in such settings. © 2010 Australasian Professional Society on Alcohol and other Drugs.

  12. Non-Blocking Concurrent Imperative Programming with Session Types

    Directory of Open Access Journals (Sweden)

    Miguel Silva

    2017-01-01

    Full Text Available Concurrent C0 is an imperative programming language in the C family with session-typed message-passing concurrency. The previously proposed semantics implements asynchronous (non-blocking output; we extend it here with non-blocking input. A key idea is to postpone message reception as much as possible by interpreting receive commands as a request for a message. We implemented our ideas as a translation from a blocking intermediate language to a non-blocking language. Finally, we evaluated our techniques with several benchmark programs and show the results obtained. While the abstract measure of span always decreases (or remains unchanged, only a few of the examples reap a practical benefit.

  13. Threaded cognition: an integrated theory of concurrent multitasking.

    Science.gov (United States)

    Salvucci, Dario D; Taatgen, Niels A

    2008-01-01

    The authors propose the idea of threaded cognition, an integrated theory of concurrent multitasking--that is, performing 2 or more tasks at once. Threaded cognition posits that streams of thought can be represented as threads of processing coordinated by a serial procedural resource and executed across other available resources (e.g., perceptual and motor resources). The theory specifies a parsimonious mechanism that allows for concurrent execution, resource acquisition, and resolution of resource conflicts, without the need for specialized executive processes. By instantiating this mechanism as a computational model, threaded cognition provides explicit predictions of how multitasking behavior can result in interference, or lack thereof, for a given set of tasks. The authors illustrate the theory in model simulations of several representative domains ranging from simple laboratory tasks such as dual-choice tasks to complex real-world domains such as driving and driver distraction. (c) 2008 APA, all rights reserved

  14. Process for carrying out analyses based on concurrent reactions

    Energy Technology Data Exchange (ETDEWEB)

    Glover, J S; Shepherd, B P

    1980-01-03

    The invention refers to a process for carrying out analyses based on concurrent reactions. A part of a compound to be analysed is subjected with a standard quantity of this compound in a labelled form to a common reaction with a standard quantity of a reagent, which must be less than the sum of the two parts of the reacting compound. The parts of the marked reaction compound and the labelled final compound resulting from the concurrence are separated in a tube (e.g. by centrifuging) after forced phase change (precipitation, absorption etc.) and the radio-activity of both phases in contact is measured separately. The shielded measuring device developed for this and suitable for centrifuge tubes of known dimensions is also included in the patent claims. The insulin concentration of a defined serum is measured as an example of the applications of the method (Radioimmunoassay).

  15. Reducing Concurrency Bottlenecks in Parallel I/O Workloads

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares, Adam C. [Los Alamos National Laboratory; Bent, John M. [Los Alamos National Laboratory; Wingate, Meghan [Los Alamos National Laboratory

    2011-01-01

    To enable high performance parallel checkpointing we introduced the Parallel Log Structured File System (PLFS). PLFS is middleware interposed on the file system stack to transform concurrent writing of one application file into many non-concurrently written component files. The promising effectiveness of PLFS makes it important to examine its performance for workloads other than checkpoint capture, notably the different ways that state snapshots may be later read, to make the case for using PLFS in the Exascale I/O stack. Reading a PLFS file involved reading each of its component files. In this paper we identify performance limitations on broader workloads in an early version of PLFS, specifically the need to build and distribute an index for the overall file, and the pressure on the underlying parallel file system's metadata server, and show how PLFS's decomposed components architecture can be exploited to alleviate bottlenecks in the underlying parallel file system.

  16. Nonlinear hyperbolic waves in multidimensions

    CERN Document Server

    Prasad, Phoolan

    2001-01-01

    The propagation of curved, nonlinear wavefronts and shock fronts are very complex phenomena. Since the 1993 publication of his work Propagation of a Curved Shock and Nonlinear Ray Theory, author Phoolan Prasad and his research group have made significant advances in the underlying theory of these phenomena. This volume presents their results and provides a self-contained account and gradual development of mathematical methods for studying successive positions of these fronts.Nonlinear Hyperbolic Waves in Multidimensions includes all introductory material on nonlinear hyperbolic waves and the theory of shock waves. The author derives the ray theory for a nonlinear wavefront, discusses kink phenomena, and develops a new theory for plane and curved shock propagation. He also derives a full set of conservation laws for a front propagating in two space dimensions, and uses these laws to obtain successive positions of a front with kinks. The treatment includes examples of the theory applied to converging wavefronts...

  17. Cubication of conservative nonlinear oscillators

    International Nuclear Information System (INIS)

    Belendez, Augusto; Alvarez, Mariela L; Fernandez, Elena; Pascual, Inmaculada

    2009-01-01

    A cubication procedure of the nonlinear differential equation for conservative nonlinear oscillators is analysed and discussed. This scheme is based on the Chebyshev series expansion of the restoring force, and this allows us to approximate the original nonlinear differential equation by a Duffing equation in which the coefficients for the linear and cubic terms depend on the initial amplitude, A, while in a Taylor expansion of the restoring force these coefficients are independent of A. The replacement of the original nonlinear equation by an approximate Duffing equation allows us to obtain an approximate frequency-amplitude relation as a function of the complete elliptic integral of the first kind. Some conservative nonlinear oscillators are analysed to illustrate the usefulness and effectiveness of this scheme.

  18. Cooperative Planning, Uncertainty, and Managerial Control in Concurrent Design

    OpenAIRE

    Victoria L. Mitchell; Barrie R. Nault

    2007-01-01

    We examine whether cooperative planning and uncertainty affect the magnitude of rework in concurrent engineering projects with upstream and downstream operations, and explore the impact of such rework on project delays. Using survey data from a sample of 120 business process (BP) redesign and related information technology (IT) development projects in healthcare and telecommunications, our results indicate that upstream (BP) rework and downstream (IT) rework is mediated and mitigated by coope...

  19. Prostatic Adenocarcinoma with Concurrent Sertoli Cell Tumor in a Dog

    Science.gov (United States)

    Gill, C. W.

    1981-01-01

    A case of metastatic prostatic adenocarcinoma with concurrent Sertoli cell tumor is presented in an old, miniature Schnauzer dog. The prostatic neoplasm was highly anaplastic and had metastasized widely. Clinical signs were compatible with increased estrogen production. It is interesting to note that the prostatic carcinoma, usually considered to be androgen dependent, developed and metastasized, despite the presence of apparently increased estrogen levels. ImagesFigure 1.Figure 2.Figure 3.Figure 4.Figure 5.Figure 6. PMID:7340923

  20. The Application of Concurrent Engineering in Infrastructure Projects

    OpenAIRE

    Wolden, Sigurd

    2017-01-01

    The construction industry today is considered to be lagging competitively behind in comparison to other industries. The reason for this is thought of by many researchers to be the fragmented project process, the traditional principles and the, sometimes adversarial environment. In order to solve some of these obstacles and at the same time enhance productivity, the Norwegian infrastructure sector has recently developed an interest towards the project management method Concurrent Engineering (...

  1. Irritable bowel syndrome: The incidence of concurrent psychopathology

    OpenAIRE

    Margie H Wilson; Anita D Stuart; H Gertie Pretorius

    1999-01-01

    The goal of this study was to improve understanding of the association between physiology and psychology in Functional Gastrointestinal disorders by considering the co-morbidity of lrritable Bowel Syndrome and psychopathology in a sector of the South African population. A comparison was made between the incidence of concurrent psychopathology in a sample of 48 white female patients, aged 25 to 55 years and diagnosed with lrritable Bowel Syndrome and the incidence of psychopathology in a contr...

  2. A Concurrent Programming Language for Arduino and Educational Robotics

    OpenAIRE

    Morán, Ricardo; Teragni, Matías; Zabala, Gonzalo

    2017-01-01

    Arduino is currently one of the most popular platforms for educational robotics due to its low cost and large amount of available resources online. The Arduino software library provides an abstraction layer over the hardware details, making it possible for novices to build interesting projects. However, its lack of support for concurrency makes some educational robotics projects difficult. In this paper, we explore different approaches to solve this problem and we propose the implementation o...

  3. Rain: A New Concurrent Process-Oriented Programming Language

    OpenAIRE

    Brown, Neil C.C.

    2006-01-01

    This paper details the design of a new concurrent process-oriented programming language, Rain. The language borrows heavily from occam-p and C++ to create a new language based on process-oriented programming, marrying channel-based communication, a clear division between statement and expression, and elements of functional programming. An expressive yet simple type system, coupled with templates, underpins the language. Modern features such as Unicode support and 64-bit integers are included ...

  4. Personality and Career Success: Concurrent and Longitudinal Relations

    OpenAIRE

    Sutin, Angelina R.; Costa, Paul T.; Miech, Richard; Eaton, William W.

    2009-01-01

    The present research addresses the dynamic transaction between extrinsic (occupational prestige, income) and intrinsic (job satisfaction) career success and the Five-Factor Model of personality. Participants (N = 731) completed a comprehensive measure of personality and reported their job title, annual income, and job satisfaction; a subset of these participants (n = 302) provided the same information approximately 10 years later. Measured concurrently, emotionally stable and conscientious pa...

  5. Concurrent Programming Using Actors: Exploiting Large-Scale Parallelism,

    Science.gov (United States)

    1985-10-07

    ORGANIZATION NAME AND ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK* Artificial Inteligence Laboratory AREA Is WORK UNIT NUMBERS 545 Technology Square...D-R162 422 CONCURRENT PROGRMMIZNG USING f"OS XL?ITP TEH l’ LARGE-SCALE PARALLELISH(U) NASI AC E Al CAMBRIDGE ARTIFICIAL INTELLIGENCE L. G AGHA ET AL...RESOLUTION TEST CHART N~ATIONAL BUREAU OF STANDA.RDS - -96 A -E. __ _ __ __’ .,*- - -- •. - MASSACHUSETTS INSTITUTE OF TECHNOLOGY ARTIFICIAL

  6. Cauldrons: An Abstraction for Concurrent Problems Solving. Revision.

    Science.gov (United States)

    1986-09-01

    PROGRAM ELEMENT. PROJECT. TASK Artificial Inteligence Laboratory ARtA G WORK UNIT NUMVERS S 545 Technology Square etJ Cambridge, MA 02139 TIM II...D-11194 12611 CAU1,LDRONS: AN ROSTRACTION FOR CONCURRENT PROBLEMS1/ RSOLVING REYISION(U) MASSACHUSETTS INST OF TECHCANIRIDGE ARTIFICIAL INTELLIGENCE...is described, accompanied by cxanmple of their application to various domains. ’lhis report describes research done at both the MIT Artificial

  7. Management and Surgical Outcomes of Concurrent Tuberculosis and Lung Cancer.

    Science.gov (United States)

    Evman, Serdar; Baysungur, Volkan; Alpay, Levent; Uskul, Bahadir; Misirlioglu, Aysun Kosif; Kanbur, Serda; Dogruyol, Talha

    2017-10-01

    Background  Concurrent pulmonary tuberculosis (TB) and lung cancer are rarely encountered in Western countries; however, it is more common in developing countries. We aim to share the diagnostic and treatment approaches in this study. Materials and Methods  Clinical files of all patients undergoing lung resection for non-small cell carcinoma with concurrent pulmonary TB between February 2006 and December 2012 were investigated retrospectively in terms of patient characteristics, operation methods, definite pathology and stage of tumor, postoperative treatment schemes, and associated complications. Results  TB was detected in 17 (1.3%) of 1,266 operated carcinoma patients. Eleven had squamous cell carcinoma and six had adenocarcinoma. Mean age was 54.9 years. Two patients received anti-TB treatment preoperatively. Fifteen patients were given anti-TB treatment postoperatively, as soon as definite microbiological confirmation was obtained, and concurrently given adjuvant therapy after 3 weeks of sole four-drug TB treatment. Pneumonectomy was performed in four (23.5%), sleeve lobectomy in three (17.6%), lobectomy in eight (47%), and bilobectomy in two (11.7%) patients. Postoperative complications occurred in four (23.5%) patients, with bronchopleural fistula being seen in only one pneumonectomy patient. No postoperative mortality or reactivation of TB was seen. Mean survival time was 32 ± 2 months. Conclusion  Resection following a 3-week anti-TB treatment or concurrent anti-TB and postoperative adjuvant chemotherapy does not constitute an additional postoperative risk for patients with concomitant lung malignancy and pulmonary TB. The determination of optimum treatment for these patients presents a challenge in developing countries, where TB is still a common disease. Georg Thieme Verlag KG Stuttgart · New York.

  8. Actors: A Model of Concurrent Computation in Distributed Systems.

    Science.gov (United States)

    1985-06-01

    Artificial Intelligence Labora- tory of the Massachusetts Institute of Technology. Support for the labora- tory’s aritificial intelligence research is...RD-A157 917 ACTORS: A MODEL OF CONCURRENT COMPUTATION IN 1/3- DISTRIBUTED SY𔃿TEMS(U) MASSACHUSETTS INST OF TECH CRMBRIDGE ARTIFICIAL INTELLIGENCE ...Computation In Distributed Systems Gui A. Aghai MIT Artificial Intelligence Laboratory Thsdocument ha. been cipp-oved I= pblicrelease and sale; itsI

  9. Concurrent Smalltalk on the Message-Driven Processor

    Science.gov (United States)

    1991-09-01

    language close to Concurrent Smalltalk and having an almost identical name is CONCURRENTSMALLTALK [39] [40] independently developed by Yasuhiko Yokote and...Laboratory Memo 1044, October 1988. [391 Yokote, Yasuhiko , and Tokoro, Mario. ’The Design and Implementation of Concur- rentSmalltalk." Proceedings...of the 1986 Object-Oriented Programming Systems, Lan- guages, and Applications Conference, September 1986. 222 Bibliography [401 Yokote, Yasuhiko , and

  10. Concurrent split cord malformation and teratoma: dysembryology, presentation, and treatment.

    Science.gov (United States)

    Babu, Ranjith; Reynolds, Renee; Moreno, Jessica R; Cummings, Thomas J; Bagley, Carlos A

    2014-02-01

    Split cord malformation (SCM) is a rare form of spinal dysraphism in which the spinal cord is divided in the sagittal plane, forming a double neural tube. In addition to being associated with a variety of malformations, SCM may occur with spinal cord tumors, with only exceptional cases involving teratomas. As only eight patients with a teratoma associated with SCM have been reported, their presentation characteristics and treatment are currently unclear. We review the literature of all patients with SCM with concurrent spinal teratoma, discuss the potential dysembryology, and report the first case of SCM with concurrent spinal teratoma in an elderly patient. The mean age of those with concurrent SCM and teratomas was 39.4 years, with 55.6% occurring in females. The lumbar spine was the most frequent location for teratomas (66.7%), with the Type II malformation more commonly occurring with these tumors (75%). The duration of symptoms varied widely, ranging from 1 month to 5 years, with the average duration being nearly 2 years. Back pain (87.5%) and lower extremity weakness (75%) were the most common presenting symptoms. As SCM may be associated with progressive neurological deterioration and teratomas can contain immature or malignant components, surgery should be attempted with the goal of gross total resection. Nonetheless, in patients with a concurrent tumor and spinal dysraphism, spinal teratomas should be considered in the differential diagnosis. Gross total resection of these lesions may be safely achieved even in the presence of SCM using intraoperative electrophysiologic monitoring. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Concurrent Use of Cigarettes and Smokeless Tobacco in Minnesota

    Directory of Open Access Journals (Sweden)

    Raymond G. Boyle

    2012-01-01

    Full Text Available Cigarette smokers are being encouraged to use smokeless tobacco (SLT in locations where smoking is banned. We examined state-wide data from Minnesota to measure changes over time in the use of SLT and concurrent use of cigarettes and SLT. The Minnesota Adult Tobacco Survey was conducted four times between 1999 and 2010 and has provided state-wide estimates of cigarette smoking, SLT use and concurrent use of SLT by smokers. The prevalence of SLT was essentially unchanged through 2007, then increased significantly between 2007 and 2010 (3.1% versus 4.3%, P<0.05. Similarly, the prevalence of cigarette smokers who reported using SLT was stable then increased between 2007 and 2010 (4.4% versus 9.6%, P<0.05. The finding of higher SLT use by smokers could indicate that smokers in Minnesota are in an experimental phase of testing alternative products as they adjust to recent public policies restricting smoking in public places. The findings are suggestive that some Minnesota smokers are switching to concurrent use of cigarettes and SLT. Future surveillance reports will be necessary to confirm the results.

  12. Cutaneous xanthomas with concurrent demodicosis and dermatophytosis in a cat.

    Science.gov (United States)

    Vogelnest, L J

    2001-07-01

    Multiple cutaneous xanthomas, associated with fasting hyperlipidaemia, are described in a 9-month-old domestic long-haired cat. A severely pruritic, papular, and crusting dermatitis affecting the head and neck, initially diagnosed as lesions of the eosinophilic granuloma complex, progressively developed on the head and pinnae. Pruritus was controlled with administration of prednisolone and chlorambucil. Repeat histological examination confirmed the diagnosis of cutaneous xanthoma and concurrent mild demodicosis. Marked fasting hypercholesterolaemia, hypertriglyceridaemia and transient hyperglycaemia were subsequently confirmed. Treatment for hyperlipidaemia and xanthomas with a low-fat diet (Hill's Feline r/d) and the previously unreported treatment for feline demodicosis of daily oral milbemycin were commenced. Multiple pink, alopecic plaques and papules gradually regressed, however pruritus recurred if immunosuppressive treatment was reduced, and well-demarcated areas of alopecia developed on the head, limbs and trunk, despite negative skin scrapings for demodex mites. Fungal culture of hair samples yielded Microsporum canis. All cutaneous lesions resolved with the addition of griseofulvin to the treatment regimen. Concurrent corneal ulceration and keratoconjunctivitis sicca ultimately resolved with treatment, including topical cyclosporin. Diabetes mellitus developed 6 months after resolution of skin lesions. No cutaneous or ocular abnormalities were present 6 months later with continued low-fat diet and insulin administration, although transient recurrence of papules and pruritus occurred after inadvertent access to a fatty meal. An underlying primary hyperlipidaemia was suspected, causing pruritic xanthomas. This may represent the first report of concurrent cutaneous xanthomas, demodicosis and dermatophytosis in a cat.

  13. Iterative concurrent reconstruction algorithms for emission computed tomography

    International Nuclear Information System (INIS)

    Brown, J.K.; Hasegawa, B.H.; Lang, T.F.

    1994-01-01

    Direct reconstruction techniques, such as those based on filtered backprojection, are typically used for emission computed tomography (ECT), even though it has been argued that iterative reconstruction methods may produce better clinical images. The major disadvantage of iterative reconstruction algorithms, and a significant reason for their lack of clinical acceptance, is their computational burden. We outline a new class of ''concurrent'' iterative reconstruction techniques for ECT in which the reconstruction process is reorganized such that a significant fraction of the computational processing occurs concurrently with the acquisition of ECT projection data. These new algorithms use the 10-30 min required for acquisition of a typical SPECT scan to iteratively process the available projection data, significantly reducing the requirements for post-acquisition processing. These algorithms are tested on SPECT projection data from a Hoffman brain phantom acquired with a 2 x 10 5 counts in 64 views each having 64 projections. The SPECT images are reconstructed as 64 x 64 tomograms, starting with six angular views. Other angular views are added to the reconstruction process sequentially, in a manner that reflects their availability for a typical acquisition protocol. The results suggest that if T s of concurrent processing are used, the reconstruction processing time required after completion of the data acquisition can be reduced by at least 1/3 T s. (Author)

  14. Association between bacterial vaginosis and partner concurrency: a longitudinal study.

    Science.gov (United States)

    Kenyon, Chris R; Buyze, Jozefien; Klebanoff, Mark; Brotman, Rebecca M

    2018-02-01

    The study aimed to test if there was an association between prevalent bacterial vaginosis (BV) and women reporting that their partner had other partners at the same time (partner concurrency). This association has not been assessed in a longitudinal cohort. The Longitudinal Study of Vaginal Flora recruited a cohort of 3620 non-pregnant women aged 15-44 years who presented for routine primary healthcare at 12 clinics in Birmingham, Alabama. Behavioural questionnaires and vaginal smears were obtained quarterly for a year and BV was defined by a Nugent score 7 or higher as well as Amsel criteria. Mixed effects logistic regression was used to assess the relationship between prevalent BV and reporting that one's partner had other partners in the preceding 3-6 months time interval. Nugent score prevalent BV was associated with both reporting that one's partner definitely (adjusted OR (aOR) 1.5; 95% CI 1.2 to 1.8) and possibly (aOR 1.5; 95% CI 1.2 to 1.8) engaged in partner concurrency in the preceding 3-6 months time period. Prevalent BV diagnosed by Amsel criteria was similar. A diagnosis of prevalent BV was associated with reporting that one's partner possibly or definitely engaged in partner concurrency. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

  15. Exploiting communication concurrency on high performance computing systems

    Energy Technology Data Exchange (ETDEWEB)

    Chaimov, Nicholas [Univ. of Oregon, Eugene, OR (United States); Ibrahim, Khaled Z. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Williams, Samuel [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Iancu, Costin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2015-01-01

    Although logically available, applications may not exploit enough instantaneous communication concurrency to maximize hardware utilization on HPC systems. This is exacerbated in hybrid programming models such as SPMD+OpenMP. We present the design of a "multi-threaded" runtime able to transparently increase the instantaneous network concurrency and to provide near saturation bandwidth, independent of the application configuration and dynamic behavior. The runtime forwards communication requests from application level tasks to multiple communication servers. Our techniques alleviate the need for spatial and temporal application level message concurrency optimizations. Experimental results show improved message throughput and bandwidth by as much as 150% for 4KB bytes messages on InfiniBand and by as much as 120% for 4KB byte messages on Cray Aries. For more complex operations such as all-to-all collectives, we observe as much as 30% speedup. This translates into 23% speedup on 12,288 cores for a NAS FT implemented using FFTW. We also observe as much as 76% speedup on 1,500 cores for an already optimized UPC+OpenMP geometric multigrid application using hybrid parallelism.

  16. Concurrent chemoradiotherapy for advanced hypopharyngeal or cervical esophageal cancer

    International Nuclear Information System (INIS)

    Endo, Sohei; Hamada, Norihisa; Shigihara, Shuntaro

    2001-01-01

    Chemotherapy has been shown to be most effective when delivered concurrently with radiation for patients with untreated advanced-stage tumors. We conducted a concurrent chemoradiation protocol using systemic infusion of Cisplatin (CDDP) and 5-Fluorouracil (FU), followed by radical surgery. Thirty-six patients with advanced hypopharyngeal (n=28) or cervical esophageal cancer (n=8) received intravenous administration of CDDP (100 mg/m 2 ), followed by a 120-hour continuous infusion of 5-FU (1000 mg/m 2 /day), and concomitant radiotherapy (200 cGy/day x 20-35 fractions). One patient died of aspiration pneumonia. The rate of grade 3-4 hematological chemotoxicity was 27.8% (10/36). Pharyngo-laryngo-cervical esophagectomies were performed in 23 patients, one received partial resection of the hypopharynx, and one received radical neck dissection. Ten remaining patients refused radical surgery. In the resected specimens, 11 out of 24 (46%) were confirmed as complete response (CR). The median length of follow-up was 74.5 weeks. The projected 5-year survival was 39.7%. When the patients who had refused radical surgery for residual tumor were excluded, the 5-year survival rate rose up to 70.0% in the patients with hypopharyngeal cancer. Concurrent chemoradiotherapy can be safely and effectively applied. Preliminary pathological results indicate the possibility in improving the rate of organ preservation. (author)

  17. Nonlinear Ritz approximation for Fredholm functionals

    Directory of Open Access Journals (Sweden)

    Mudhir A. Abdul Hussain

    2015-11-01

    Full Text Available In this article we use the modify Lyapunov-Schmidt reduction to find nonlinear Ritz approximation for a Fredholm functional. This functional corresponds to a nonlinear Fredholm operator defined by a nonlinear fourth-order differential equation.

  18. Breatherlike impurity modes in discrete nonlinear lattices

    DEFF Research Database (Denmark)

    Hennig, D.; Rasmussen, Kim; Tsironis, G. P.

    1995-01-01

    We investigate the properties of a disordered generalized discrete nonlinear Schrodinger equation, containing both diagonal and nondiagonal nonlinear terms. The equation models a Linear host lattice doped with nonlinear impurities. We find different types of impurity states that form itinerant...

  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. The Challenges of Career and Technical Education Concurrent Enrollment: An Administrative Perspective

    Science.gov (United States)

    Haag, Patricia W.

    2015-01-01

    Career and technical education concurrent enrollment may pose unique challenges in programming and enrollment for program administrators, and this chapter describes the experiences and challenges of a CTE concurrent enrollment administrator.

  1. Cumulative cisplatin dose in concurrent chemoradiotherapy for head and neck cancer : A systematic review

    NARCIS (Netherlands)

    Strojan, Primoz; Vermorken, Jan B.; Beitler, Jonathan J.; Saba, Nabil F.; Haigentz, Missak; Bossi, Paolo; Worden, Francis P.; Langendijk, Johannes A.; Eisbruch, Avraham; Mendenhall, William M.; Lee, Anne W. M.; Harrison, Louis B.; Bradford, Carol R.; Smee, Robert; Silver, Carl E.; Rinaldo, Alessandra; Ferlito, Alfio

    Background. The optimal cumulative dose and timing of cisplatin administration in various concurrent chemoradiotherapy protocols for nonmetastatic head and neck squamous cell carcinoma (HNSCC) has not been determined. Methods. The absolute survival benefit at 5 years of concurrent chemoradiotherapy

  2. Spatial solitons in nonlinear photonic crystals

    DEFF Research Database (Denmark)

    Corney, Joel Frederick; Bang, Ole

    2000-01-01

    We study solitons in one-dimensional quadratic nonlinear photonic crystals with periodic linear and nonlinear susceptibilities. We show that such crystals support stable bright and dark solitons, even when the effective quadratic nonlinearity is zero.......We study solitons in one-dimensional quadratic nonlinear photonic crystals with periodic linear and nonlinear susceptibilities. We show that such crystals support stable bright and dark solitons, even when the effective quadratic nonlinearity is zero....

  3. Super-nonlinear fluorescence microscopy for high-contrast deep tissue imaging

    Science.gov (United States)

    Wei, Lu; Zhu, Xinxin; Chen, Zhixing; Min, Wei

    2014-02-01

    Two-photon excited fluorescence microscopy (TPFM) offers the highest penetration depth with subcellular resolution in light microscopy, due to its unique advantage of nonlinear excitation. However, a fundamental imaging-depth limit, accompanied by a vanishing signal-to-background contrast, still exists for TPFM when imaging deep into scattering samples. Formally, the focusing depth, at which the in-focus signal and the out-of-focus background are equal to each other, is defined as the fundamental imaging-depth limit. To go beyond this imaging-depth limit of TPFM, we report a new class of super-nonlinear fluorescence microscopy for high-contrast deep tissue imaging, including multiphoton activation and imaging (MPAI) harnessing novel photo-activatable fluorophores, stimulated emission reduced fluorescence (SERF) microscopy by adding a weak laser beam for stimulated emission, and two-photon induced focal saturation imaging with preferential depletion of ground-state fluorophores at focus. The resulting image contrasts all exhibit a higher-order (third- or fourth- order) nonlinear signal dependence on laser intensity than that in the standard TPFM. Both the physical principles and the imaging demonstrations will be provided for each super-nonlinear microscopy. In all these techniques, the created super-nonlinearity significantly enhances the imaging contrast and concurrently extends the imaging depth-limit of TPFM. Conceptually different from conventional multiphoton processes mediated by virtual states, our strategy constitutes a new class of fluorescence microscopy where high-order nonlinearity is mediated by real population transfer.

  4. LDRD report nonlinear model reduction

    Energy Technology Data Exchange (ETDEWEB)

    Segalman, D.; Heinstein, M.

    1997-09-01

    The very general problem of model reduction of nonlinear systems was made tractable by focusing on the very large subclass consisting of linear subsystems connected by nonlinear interfaces. Such problems constitute a large part of the nonlinear structural problems encountered in addressing the Sandia missions. A synthesis approach to this class of problems was developed consisting of: detailed modeling of the interface mechanics; collapsing the interface simulation results into simple nonlinear interface models; constructing system models by assembling model approximations of the linear subsystems and the nonlinear interface models. These system models, though nonlinear, would have very few degrees of freedom. A paradigm problem, that of machine tool vibration, was selected for application of the reduction approach outlined above. Research results achieved along the way as well as the overall modeling of a specific machine tool have been very encouraging. In order to confirm the interface models resulting from simulation, it was necessary to develop techniques to deduce interface mechanics from experimental data collected from the overall nonlinear structure. A program to develop such techniques was also pursued with good success.

  5. A Testing Platform for Durability Studies of Polymers and Fiber-reinforced Polymer Composites under Concurrent Hygrothermo-mechanical Stimuli

    Science.gov (United States)

    Gomez, Antonio; Pires, Robert; Yambao, Alyssa; La Saponara, Valeria

    2014-01-01

    The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus. PMID:25548950

  6. A testing platform for durability studies of polymers and fiber-reinforced polymer composites under concurrent hygrothermo-mechanical stimuli.

    Science.gov (United States)

    Gomez, Antonio; Pires, Robert; Yambao, Alyssa; La Saponara, Valeria

    2014-12-11

    The durability of polymers and fiber-reinforced polymer composites under service condition is a critical aspect to be addressed for their robust designs and condition-based maintenance. These materials are adopted in a wide range of engineering applications, from aircraft and ship structures, to bridges, wind turbine blades, biomaterials and biomedical implants. Polymers are viscoelastic materials, and their response may be highly nonlinear and thus make it challenging to predict and monitor their in-service performance. The laboratory-scale testing platform presented herein assists the investigation of the influence of concurrent mechanical loadings and environmental conditions on these materials. The platform was designed to be low-cost and user-friendly. Its chemically resistant materials make the platform adaptable to studies of chemical degradation due to in-service exposure to fluids. An example of experiment was conducted at RT on closed-cell polyurethane foam samples loaded with a weight corresponding to ~50% of their ultimate static and dry load. Results show that the testing apparatus is appropriate for these studies. Results also highlight the larger vulnerability of the polymer under concurrent loading, based on the higher mid-point displacements and lower residual failure loads. Recommendations are made for additional improvements to the testing apparatus.

  7. 7 CFR 1610.6 - Concurrent Bank and RUS cost-of-money loans.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Concurrent Bank and RUS cost-of-money loans. 1610.6..., DEPARTMENT OF AGRICULTURE LOAN POLICIES § 1610.6 Concurrent Bank and RUS cost-of-money loans. (a) The Bank makes loans, under section 408 of the Act, concurrently with RUS cost-of-money loans made under section...

  8. An Implementation of the Object-Oriented Concurrent Programming Language SINA

    NARCIS (Netherlands)

    Triphathi, Anand; Berge, Eric; Aksit, Mehmet

    SINA is an object-oriented language for distributed and concurrent programming. The primary focus of this paper is on the object-oriented concurrent programming mechanisms of SINA and their implementation. This paper presents the SINA constructs for concurrent programming and inter-object

  9. Nonlinear time heteronymous damping in nonlinear parametric planetary systems

    Czech Academy of Sciences Publication Activity Database

    Hortel, Milan; Škuderová, Alena

    2014-01-01

    Roč. 225, č. 7 (2014), s. 2059-2073 ISSN 0001-5970 Institutional support: RVO:61388998 Keywords : nonlinear dynamics * planetary systems * heteronymous damping Subject RIV: JT - Propulsion, Motors ; Fuels Impact factor: 1.465, year: 2014

  10. Design with Nonlinear Constraints

    KAUST Repository

    Tang, Chengcheng

    2015-12-10

    Most modern industrial and architectural designs need to satisfy the requirements of their targeted performance and respect the limitations of available fabrication technologies. At the same time, they should reflect the artistic considerations and personal taste of the designers, which cannot be simply formulated as optimization goals with single best solutions. This thesis aims at a general, flexible yet e cient computational framework for interactive creation, exploration and discovery of serviceable, constructible, and stylish designs. By formulating nonlinear engineering considerations as linear or quadratic expressions by introducing auxiliary variables, the constrained space could be e ciently accessed by the proposed algorithm Guided Projection, with the guidance of aesthetic formulations. The approach is introduced through applications in different scenarios, its effectiveness is demonstrated by examples that were difficult or even impossible to be computationally designed before. The first application is the design of meshes under both geometric and static constraints, including self-supporting polyhedral meshes that are not height fields. Then, with a formulation bridging mesh based and spline based representations, the application is extended to developable surfaces including origami with curved creases. Finally, general approaches to extend hard constraints and soft energies are discussed, followed by a concluding remark outlooking possible future studies.

  11. Nonlinear functional analysis

    CERN Document Server

    Deimling, Klaus

    1985-01-01

    topics. However, only a modest preliminary knowledge is needed. In the first chapter, where we introduce an important topological concept, the so-called topological degree for continuous maps from subsets ofRn into Rn, you need not know anything about functional analysis. Starting with Chapter 2, where infinite dimensions first appear, one should be familiar with the essential step of consider­ ing a sequence or a function of some sort as a point in the corresponding vector space of all such sequences or functions, whenever this abstraction is worthwhile. One should also work out the things which are proved in § 7 and accept certain basic principles of linear functional analysis quoted there for easier references, until they are applied in later chapters. In other words, even the 'completely linear' sections which we have included for your convenience serve only as a vehicle for progress in nonlinearity. Another point that makes the text introductory is the use of an essentially uniform mathematical languag...

  12. Scalable Nonlinear Compact Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debojyoti [Argonne National Lab. (ANL), Argonne, IL (United States); Constantinescu, Emil M. [Univ. of Chicago, IL (United States); Brown, Jed [Univ. of Colorado, Boulder, CO (United States)

    2014-04-01

    In this work, we focus on compact schemes resulting in tridiagonal systems of equations, specifically the fifth-order CRWENO scheme. We propose a scalable implementation of the nonlinear compact schemes by implementing a parallel tridiagonal solver based on the partitioning/substructuring approach. We use an iterative solver for the reduced system of equations; however, we solve this system to machine zero accuracy to ensure that no parallelization errors are introduced. It is possible to achieve machine-zero convergence with few iterations because of the diagonal dominance of the system. The number of iterations is specified a priori instead of a norm-based exit criterion, and collective communications are avoided. The overall algorithm thus involves only point-to-point communication between neighboring processors. Our implementation of the tridiagonal solver differs from and avoids the drawbacks of past efforts in the following ways: it introduces no parallelization-related approximations (multiprocessor solutions are exactly identical to uniprocessor ones), it involves minimal communication, the mathematical complexity is similar to that of the Thomas algorithm on a single processor, and it does not require any communication and computation scheduling.

  13. Acoustic-gravity nonlinear structures

    Directory of Open Access Journals (Sweden)

    D. Jovanović

    2002-01-01

    Full Text Available A catalogue of nonlinear vortex structures associated with acoustic-gravity perturbations in the Earth's atmosphere is presented. Besides the previously known Kelvin-Stewart cat's eyes, dipolar and tripolar structures, new solutions having the form of a row of counter-rotating vortices, and several weakly two-dimensional vortex chains are given. The existence conditions for these nonlinear structures are discussed with respect to the presence of inhomogeneities of the shear flows. The mode-coupling mechanism for the nonlinear generation of shear flows in the presence of linearly unstable acoustic-gravity waves, possibly also leading to intermittency and chaos, is presented.

  14. Nonlinear Dynamic Phenomena in Mechanics

    CERN Document Server

    Warminski, Jerzy; Cartmell, Matthew P

    2012-01-01

    Nonlinear phenomena should play a crucial role in the design and control of engineering systems and structures as they can drastically change the prevailing dynamical responses. This book covers theoretical and applications-based problems of nonlinear dynamics concerned with both discrete and continuous systems of interest in civil and mechanical engineering. They include pendulum-like systems, slender footbridges, shape memory alloys, sagged elastic cables and non-smooth problems. Pendulums can be used as a dynamic absorber mounted in high buildings, bridges or chimneys. Geometrical nonlinear

  15. Non-linear optical materials

    CERN Document Server

    Saravanan, R

    2018-01-01

    Non-linear optical materials have widespread and promising applications, but the efforts to understand the local structure, electron density distribution and bonding is still lacking. The present work explores the structural details, the electron density distribution and the local bond length distribution of some non-linear optical materials. It also gives estimation of the optical band gap, the particle size, crystallite size, and the elemental composition from UV-Visible analysis, SEM, XRD and EDS of some non-linear optical materials respectively.

  16. Nonlinear modulation of ionization waves

    International Nuclear Information System (INIS)

    Bekki, Naoaki

    1981-01-01

    In order to investigate the nonlinear characteristics of ionization waves (moving-striations) in the positive column of glow discharge, a nonlinear modulation of ionization waves in the region of the Pupp critical current is analysed by means of the reductive perturbation method. The modulation of ionization waves is described by a nonlinear Schroedinger type equation. The coefficients of the equation are evaluated using the data of the low pressure Argon-discharge, and the simple solutions (plane wave and envelope soliton type solutions) are presented. Under a certain condition an envelope soliton is propagated through the positive column. (author)

  17. Single-shot measurement of nonlinear absorption and nonlinear refraction.

    Science.gov (United States)

    Jayabalan, J; Singh, Asha; Oak, Shrikant M

    2006-06-01

    A single-shot method for measurement of nonlinear optical absorption and refraction is described and analyzed. A spatial intensity variation of an elliptical Gaussian beam in conjugation with an array detector is the key element of this method. The advantages of this single-shot technique were demonstrated by measuring the two-photon absorption and free-carrier absorption in GaAs as well as the nonlinear refractive index of CS2 using a modified optical Kerr setup.

  18. Nonlinear optics principles and applications

    CERN Document Server

    Li, Chunfei

    2017-01-01

    This book reflects the latest advances in nonlinear optics. Besides the simple, strict mathematical deduction, it also discusses the experimental verification and possible future applications, such as the all-optical switches. It consistently uses the practical unit system throughout. It employs simple physical images, such as "light waves" and "photons" to systematically explain the main principles of nonlinear optical effects. It uses the first-order nonlinear wave equation in frequency domain under the condition of “slowly varying amplitude approximation" and the classical model of the interaction between the light and electric dipole. At the same time, it also uses the rate equations based on the energy-level transition of particle systems excited by photons and the energy and momentum conservation principles to explain the nonlinear optical phenomenon. The book is intended for researchers, engineers and graduate students in the field of the optics, optoelectronics, fiber communication, information tech...

  19. Nonlinear Dynamics in Spear Wigglers

    International Nuclear Information System (INIS)

    2002-01-01

    BL11, the most recently installed wiggler in the SPEAR storage ring at SSRL, produces a large nonlinear perturbation of the electron beam dynamics, which was not directly evident in the integrated magnetic field measurements. Measurements of tune shifts with betatron oscillation amplitude and with closed orbit shifts were used to characterize the nonlinear fields of the SPEAR insertion devices (IDs). Because of the narrow pole width in BL11, the nonlinear fields seen along the wiggling electron trajectory are dramatically different than the flip coil measurements made along a straight line. This difference explains the tune shift measurements and the observed degradation in dynamic aperture. Corrector magnets to cancel the BL11 nonlinear fields are presently under construction

  20. Device Applications of Nonlinear Dynamics

    CERN Document Server

    Baglio, Salvatore

    2006-01-01

    This edited book is devoted specifically to the applications of complex nonlinear dynamic phenomena to real systems and device applications. While in the past decades there has been significant progress in the theory of nonlinear phenomena under an assortment of system boundary conditions and preparations, there exist comparatively few devices that actually take this rich behavior into account. "Device Applications of Nonlinear Dynamics" applies and exploits this knowledge to make devices which operate more efficiently and cheaply, while affording the promise of much better performance. Given the current explosion of ideas in areas as diverse as molecular motors, nonlinear filtering theory, noise-enhanced propagation, stochastic resonance and networked systems, the time is right to integrate the progress of complex systems research into real devices.

  1. Nonlinear programming analysis and methods

    CERN Document Server

    Avriel, Mordecai

    2012-01-01

    This text provides an excellent bridge between principal theories and concepts and their practical implementation. Topics include convex programming, duality, generalized convexity, analysis of selected nonlinear programs, techniques for numerical solutions, and unconstrained optimization methods.

  2. q-Deformed nonlinear maps

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 64; Issue 3 ... Keywords. Nonlinear dynamics; logistic map; -deformation; Tsallis statistics. ... As a specific example, a -deformation procedure is applied to the logistic map. Compared ...

  3. Born-Infeld Nonlinear Electrodynamics

    International Nuclear Information System (INIS)

    Bialynicki-Birula, I.

    1999-01-01

    This is only a summary of a lecture delivered at the Infeld Centennial Meeting. In the lecture the history of the Born-Infeld nonlinear electrodynamics was presented and some general features of the theory were discussed. (author)

  4. Nonlinear compression of optical solitons

    Indian Academy of Sciences (India)

    linear pulse propagation is the nonlinear Schrödinger (NLS) equation [1]. There are ... Optical pulse compression finds important applications in optical fibres. The pulse com ..... to thank CSIR, New Delhi for financial support in the form of SRF.

  5. Nonlinear transformations of random processes

    CERN Document Server

    Deutsch, Ralph

    2017-01-01

    This concise treatment of nonlinear noise techniques encountered in system applications is suitable for advanced undergraduates and graduate students. It is also a valuable reference for systems analysts and communication engineers. 1962 edition.

  6. Extreme Nonlinear Optics An Introduction

    CERN Document Server

    Wegener, Martin

    2005-01-01

    Following the birth of the laser in 1960, the field of "nonlinear optics" rapidly emerged. Today, laser intensities and pulse durations are readily available, for which the concepts and approximations of traditional nonlinear optics no longer apply. In this regime of "extreme nonlinear optics," a large variety of novel and unusual effects arise, for example frequency doubling in inversion symmetric materials or high-harmonic generation in gases, which can lead to attosecond electromagnetic pulses or pulse trains. Other examples of "extreme nonlinear optics" cover diverse areas such as solid-state physics, atomic physics, relativistic free electrons in a vacuum and even the vacuum itself. This book starts with an introduction to the field based primarily on extensions of two famous textbook examples, namely the Lorentz oscillator model and the Drude model. Here the level of sophistication should be accessible to any undergraduate physics student. Many graphical illustrations and examples are given. The followi...

  7. Nonlinear dynamics: Challenges and perspectives

    Indian Academy of Sciences (India)

    fields such as economics, social dynamics and so on [6–10]. These nonlinear ..... developing all-optical computers in homogeneous bulk media such as pho- ... suggestions have been given to develop effective chaos-based cryptographic.

  8. Quantitative measurement of hypertrophic scar: interrater reliability and concurrent validity.

    Science.gov (United States)

    Nedelec, Bernadette; Correa, José A; Rachelska, Grazyna; Armour, Alexis; LaSalle, Léo

    2008-01-01

    Research into the pathophysiology and treatment of hypertrophic scar (HSc) remains limited by the heterogeneity of scar and the imprecision with which its severity is measured. The objective of this study was to test the interrater reliability and concurrent validity of the Cutometer measurement of elasticity, the Mexameter measurement of erythema and pigmentation, and total thickness measure of the DermaScan C relative to the modified Vancouver Scar Scale (mVSS) in patient-matched normal skin, normal scar, and HSc. Three independent investigators evaluated 128 sites (severe HSc, moderate or mild HSc, donor site, and normal skin) on 32 burn survivors using all of the above measurement tools. The intraclass correlation coefficient, which was used to measure interrater reliability, reflects the inherent amount of error in the measure and is considered acceptable when it is >0.75. Interrater reliability of the totals of the height, pliability, and vascularity subscales of the mVSS fell below the acceptable limit ( congruent with0.50). The individual subscales of the mVSS fell well below the acceptable level (0.89) for each study site with the exception of severe scar. Mexameter and DermaScan C reliability measurements were acceptable for all sites (>0.82). Concurrent validity correlations with the mVSS were significant except for the comparison of the mVSS pliability subscale and the Cutometer maximum deformation measure comparison in severe scar. In conclusion, the Mexameter and DermaScan C measurements of scar color and thickness of all sites, as well as the Cutometer measurement of elasticity in all but the most severe scars shows high interrater reliability. Their significant concurrent validity with the mVSS confirms that these tools are measuring the same traits as the mVSS, and in a more objective way.

  9. Knowledge Management tools integration within DLR's concurrent engineering facility

    Science.gov (United States)

    Lopez, R. P.; Soragavi, G.; Deshmukh, M.; Ludtke, D.

    The complexity of space endeavors has increased the need for Knowledge Management (KM) tools. The concept of KM involves not only the electronic storage of knowledge, but also the process of making this knowledge available, reusable and traceable. Establishing a KM concept within the Concurrent Engineering Facility (CEF) has been a research topic of the German Aerospace Centre (DLR). This paper presents the current KM tools of the CEF: the Software Platform for Organizing and Capturing Knowledge (S.P.O.C.K.), the data model Virtual Satellite (VirSat), and the Simulation Model Library (SimMoLib), and how their usage improved the Concurrent Engineering (CE) process. This paper also exposes the lessons learned from the introduction of KM practices into the CEF and elaborates a roadmap for the further development of KM in CE activities at DLR. The results of the application of the Knowledge Management tools have shown the potential of merging the three software platforms with their functionalities, as the next step towards the fully integration of KM practices into the CE process. VirSat will stay as the main software platform used within a CE study, and S.P.O.C.K. and SimMoLib will be integrated into VirSat. These tools will support the data model as a reference and documentation source, and as an access to simulation and calculation models. The use of KM tools in the CEF aims to become a basic practice during the CE process. The settlement of this practice will result in a much more extended knowledge and experience exchange within the Concurrent Engineering environment and, consequently, the outcome of the studies will comprise higher quality in the design of space systems.

  10. WE-D-BRE-04: Modeling Optimal Concurrent Chemotherapy Schedules

    International Nuclear Information System (INIS)

    Jeong, J; Deasy, J O

    2014-01-01

    Purpose: Concurrent chemo-radiation therapy (CCRT) has become a more common cancer treatment option with a better tumor control rate for several tumor sites, including head and neck and lung cancer. In this work, possible optimal chemotherapy schedules were investigated by implementing chemotherapy cell-kill into a tumor response model of RT. Methods: The chemotherapy effect has been added into a published model (Jeong et al., PMB (2013) 58:4897), in which the tumor response to RT can be simulated with the effects of hypoxia and proliferation. Based on the two-compartment pharmacokinetic model, the temporal concentration of chemotherapy agent was estimated. Log cell-kill was assumed and the cell-kill constant was estimated from the observed increase in local control due to concurrent chemotherapy. For a simplified two cycle CCRT regime, several different starting times and intervals were simulated with conventional RT regime (2Gy/fx, 5fx/wk). The effectiveness of CCRT was evaluated in terms of reduction in radiation dose required for 50% of control to find the optimal chemotherapy schedule. Results: Assuming the typical slope of dose response curve (γ50=2), the observed 10% increase in local control rate was evaluated to be equivalent to an extra RT dose of about 4 Gy, from which the cell-kill rate of chemotherapy was derived to be about 0.35. Best response was obtained when chemotherapy was started at about 3 weeks after RT began. As the interval between two cycles decreases, the efficacy of chemotherapy increases with broader range of optimal starting times. Conclusion: The effect of chemotherapy has been implemented into the resource-conservation tumor response model to investigate CCRT. The results suggest that the concurrent chemotherapy might be more effective when delayed for about 3 weeks, due to lower tumor burden and a larger fraction of proliferating cells after reoxygenation

  11. Nonlinear Optics: Principles and Applications

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Tidemand-Lichtenberg, Peter

    of applications, Nonlinear Optics: Principles and Applications effectively bridges physics and mathematics with relevant applied material for real-world use. The book progresses naturally from fundamental aspects to illustrative examples, and presents a strong theoretical foundation that equips the reader...... and matter, this text focuses on the physical understanding of nonlinear optics, and explores optical material response functions in the time and frequency domain....

  12. Dynamics of nonlinear feedback control

    OpenAIRE

    Snippe, H.P.; Hateren, J.H. van

    2007-01-01

    Feedback control in neural systems is ubiquitous. Here we study the mathematics of nonlinear feedback control. We compare models in which the input is multiplied by a dynamic gain (multiplicative control) with models in which the input is divided by a dynamic attenuation (divisive control). The gain signal (resp. the attenuation signal) is obtained through a concatenation of an instantaneous nonlinearity and a linear low-pass filter operating on the output of the feedback loop. For input step...

  13. On nonlinear periodic drift waves

    International Nuclear Information System (INIS)

    Kauschke, U.; Schlueter, H.

    1990-09-01

    Nonlinear periodic drift waves are investigated on the basis of a simple perturbation scheme for both the amplitude and inverse frequency. The coefficients for the generation of the forced harmonics are derived, a nonlinear dispersion relation is suggested and a criterion for the onset of the modulational instability is obtained. The results are compared with the ones obtained with the help of a standard KBM-treatment. Moreover cnoidal drift waves are suggested and compared to an experimental observation. (orig.)

  14. Competitive nonlinear pricing and bundling

    OpenAIRE

    Armstrong, Mark; Vickers, John

    2006-01-01

    We examine the impact of multiproduct nonlinear pricing on profit, consumer surplus and welfare in a duopoly. When consumers buy all their products from one firm (the one-stop shopping model), nonlinear pricing leads to higher profit and welfare, but often lower consumer surplus, than linear pricing. By contrast, in a unit-demand model where consumers may buy one product from one firm and another product from another firm, bundling generally acts to reduce profit and welfare and to boost cons...

  15. Case-based Reasoning in Conflict Negotiation in Concurrent Engineering

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Case-based reasoning (CBR) is a kind of analogous reasoning that is widely used in artificial intelligence. Conflicts are pervasive in Concurrent Engineering design environment. Conflict negotiation is necessary when conflicts occur. It is difficult to resolve conflicts due to several reasons. An approach to resolving conflicts by case-based reasoning is proposed in this paper. The knowledge representation of conflict negotiation cases, the judgment of case similarity, the retrieval model of cases, the management of case bases, and the process of case-based conflict negotiation are studied. The implementation structure of the Case-based Conflict Solving System (CCSS) is also given.

  16. Process support for Opticam: a concurrent engineering approach

    Science.gov (United States)

    Czajkowski, Walter C.; Tipps, Joe D., Jr.

    1992-12-01

    Although the principles of concurrent engineering and rapid product cycles are not new concepts in the industrial sector, the optics manufacturing industry has witnessed few technological advances since the 1940's. At present the optics industry maintains outdated stand-alone manufacturing equipment and systems that do little to foster integration or communications. 'Islands of Technology', spawned from the latest offerings of CNC controlled equipment, are generally stand alone systems incapable of supporting communication with other process equipment, not to mention the total business enterprise. This approach increases the cost in design and manufacture of optical systems while negatively impacting competitiveness in the global marketplace.

  17. Concurrent and Distributed Applications with ActoDeS

    Directory of Open Access Journals (Sweden)

    Bergenti Federico

    2016-01-01

    Full Text Available ActoDeS is a software framework for the development of large concurrent and distributed systems. This software framework takes advantage of the actor model and of an its implementation that makes easy the development of the actor code by delegating the management of events (i.e., the reception of messages to the execution environment. Moreover, it allows the development of scalable and efficient applications through the possibility of using different implementations of the components that drive the execution of actors. In particular, the paper introduces the software framework and presents the results of its experimentation.

  18. On the Expressive Power of Temporal Concurrent Constraint Programming Languages

    DEFF Research Database (Denmark)

    Nielsen, Mogens; Palamidessi, Catuscia; Valencia, Frank D.

    2002-01-01

    The tcc paradigm is a formalism for timed concurrent constraint programming. Several tcc languages differing in their way of expressing infinite behavior have been proposed in the literature. In this paper we study the expressive power of some of these languages. In particular, we show that: (1......) recursive procedures with parameters can be encoded into parameterless recursive procedures with dynamic scoping, and viceversa. (2) replication can be encoded into parameterless recursive procedures with static scoping, and viceversa. (3) the languages from (1) are strictly more expressive than...

  19. Concurrent design of an RTP chamber and advanced control system

    Energy Technology Data Exchange (ETDEWEB)

    Spence, P. [Sandia National Labs., Livermore, CA (United States); Schaper, C. [Microelectronics Control and Sensing, Inc., Mountain View, CA (United States); Kermani, A. [CVC Products, Inc., Fremont, CA (United States)

    1995-12-31

    A concurrent-engineering approach is applied to the development of an axisymmetric rapid-thermal-processing (RTP) reactor and its associated temperature controller. Using a detailed finite-element thermal model as a surrogate for actual hardware, the authors have developed and tested a multi-input multi-output (MIMO) controller. Closed-loop simulations are performed by linking the control algorithm with the finite-element code. Simulations show that good temperature uniformity is maintained on the wafer during both steady and transient conditions. A numerical study shows the effect of ramp rate, feedback gain, sensor placement, and wafer-emissivity patterns on system performance.

  20. Multiprocessor system with multiple concurrent modes of execution

    Science.gov (United States)

    Ahn, Daniel; Ceze, Luis H; Chen, Dong; Gara, Alan; Heidelberger, Philip; Ohmacht, Martin

    2013-12-31

    A multiprocessor system supports multiple concurrent modes of speculative execution. Speculation identification numbers (IDs) are allocated to speculative threads from a pool of available numbers. The pool is divided into domains, with each domain being assigned to a mode of speculation. Modes of speculation include TM, TLS, and rollback. Allocation of the IDs is carried out with respect to a central state table and using hardware pointers. The IDs are used for writing different versions of speculative results in different ways of a set in a cache memory.

  1. Concurrent tubercular and staphylococcus meningitis in a child

    Institute of Scientific and Technical Information of China (English)

    Amit Agrawal

    2009-01-01

    Spontaneous,non-surgical haematogenous Staphylococcus aureus meningitis is rare and associated with high mortality.Mixed infection causing meningitis (pyogenic and tubercular)is further rarer,poses a difficult diag-nostic and management challenge,which warrants early diagnosis and aggressive therapy.We present a case of concurrent pyogenic and tubercular meningitis in a child managed successfully.It seems that in present case initial pyogenic infection resulted in the immunocompromised state for the child that would had lead to the acti-vation of tubercular foci resulting in tubercular meningitis.

  2. Improving Construction Process through Integration and Concurrent Engineering

    Directory of Open Access Journals (Sweden)

    Malik Khalfan

    2012-11-01

    Full Text Available In an increasingly competitive business environment, improvedtime-to-market, reduced production cost, quality of the productand customer involvement are rapidly becoming the key successfactors for any product development process. Consequently, mostorganisations are moving towards the adoption of latest technologyand new management concepts and philosophies such as totalquality management and concurrent engineering (CE to bringimprovement in their product development process. This paperdiscusses the adoption of integrated processes and CE withinthe construction industry to enable construction organisations toimprove their project development process. It also discusses aproposed integrated database model for the construction projects,which should enable the construction process to improve, becomemore effective and more efficient.

  3. Type and Behaviour Reconstruction for Higher-Order Concurrent Programs

    DEFF Research Database (Denmark)

    Amtoft, T.; Nielson, Flemming; Nielson, Hanne Riis

    1997-01-01

    The authors develop a sound and complete type and behaviour inference algorithm for a fragment of CML (Standard ML with primitives for concurrency). Behaviours resemble terms of a process algebra and yield a concise representation of the communications taking place during execution; types...... are mostly as usual except that function types and `delayed communication types' are labelled by behaviours expressing the communications that will take place if the function is applied or the delayed action is activated. The development of the paper improves a previously published algorithm in achieving...

  4. An Introduction to Parallelism, Concurrency and Acceleration (1/2)

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Concurrency and parallelism are firm elements of any modern computing infrastructure, made even more prominent by the emergence of accelerators. These lectures offer an introduction to these important concepts. We will begin with a brief refresher of recent hardware offerings to modern-day programmers. We will then open the main discussion with an overview of the laws and practical aspects of scalability. Key parallelism data structures, patterns and algorithms will be shown. The main threats to scalability and mitigation strategies will be discussed in the context of real-life optimization problems.

  5. Medium Access Control for Opportunistic Concurrent Transmissions under Shadowing Channels

    Directory of Open Access Journals (Sweden)

    Seung Min Hur

    2009-06-01

    Full Text Available We study the problem of how to alleviate the exposed terminal effect in multihop wireless networks in the presence of log-normal shadowing channels. Assuming node location information, we propose an extension of the IEEE 802.11 MAC protocol that schedules concurrent transmissions in the presence of log-normal shadowing, thus mitigating the exposed terminal problem and improving network throughput and delay performance. We observe considerable improvements in throughput and delay achieved over the IEEE 802.11 MAC under various network topologies and channel conditions in ns-2 simulations, which justify the importance of considering channel randomness in MAC protocol design for multihop wireless networks.

  6. Nonlinear optics principles and applications

    CERN Document Server

    Rottwitt, Karsten

    2014-01-01

    IntroductionReview of linear opticsInduced polarizationHarmonic oscillator modelLocal field correctionsEstimated nonlinear responseSummaryTime-domain material responseThe polarization time-response functionThe Born-Oppenheimer approximationRaman scattering response function of silicaSummaryMaterial response in the frequency domain, susceptibility tensorsThe susceptibility tensorThe induced polarization in the frequency domainSum of monochromatic fieldsThe prefactor to the induced polarizationThird-order polarization in the Born-Oppenheimer approximation in the frequency domainKramers-Kronig relationsSummarySymmetries in nonlinear opticsSpatial symmetriesSecond-order materialsThird-order nonlinear materialsCyclic coordinate-systemContracted notation for second-order susceptibility tensorsSummaryThe nonlinear wave equationMono and quasi-monochromatic beamsPlane waves - the transverse problemWaveguidesVectorial approachNonlinear birefringenceSummarySecond-order nonlinear effectsGeneral theoryCoupled wave theoryP...

  7. Modeling nonlinearities in MEMS oscillators.

    Science.gov (United States)

    Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

    2013-08-01

    We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

  8. BOOK REVIEW: Nonlinear Magnetohydrodynamics

    Science.gov (United States)

    Shafranov, V.

    1998-08-01

    Nonlinear magnetohydrodynamics by Dieter Biskamp is a thorough introduction to the physics of the most impressive non-linear phenomena that occur in conducting magnetoplasmas. The basic systems, in which non-trivial dynamic processes are observed, accompanied by changes of geometry of the magnetic field and the effects of energy transformation (magnetic energy into kinetic energy or the opposite effect in magnetic dynamos), are the plasma magnetic confinement systems for nuclear fusion and space plasmas, mainly the solar plasma. A significant number of the examples of the dynamic processes considered are taken from laboratory plasmas, for which an experimental check of the theory is possible. Therefore, though the book is intended for researchers and students interested in both laboratory, including nuclear fusion, and astrophysical plasmas, it is most probably closer to the first category of reader. In the Introduction the author notes that unlike the hydrodynamics of non-conducting fluids, where the phenomena caused by rapid fluid motions are the most interesting, for plasmas in a strong magnetic field the quasi-static configurations inside which the local dynamic processes occur are often the most important. Therefore, the reader will also find in this book rather traditional material on the theory of plasma equilibrium and stability in magnetic fields. In addition, it is notable that, as opposed to a linear theory, the non-linear theory, as a rule, cannot give quite definite explanations or predictions of phenomena, and consequently there are in the book many results obtained by consideration of numerical models with the use of supercomputers. The treatment of non-linear dynamics is preceded by Chapters 2 to 4, in which the basics of MHD theory are presented with an emphasis on the role of integral invariants of the magnetic helicity type, a derivation of the reduced MHD equations is given, together with examples of the exact solutions of the equilibrium

  9. Nonlinear transport of dynamic system phase space

    International Nuclear Information System (INIS)

    Xie Xi; Xia Jiawen

    1993-01-01

    The inverse transform of any order solution of the differential equation of general nonlinear dynamic systems is derived, realizing theoretically the nonlinear transport for the phase space of nonlinear dynamic systems. The result is applicable to general nonlinear dynamic systems, with the transport of accelerator beam phase space as a typical example

  10. A reliable treatment for nonlinear Schroedinger equations

    International Nuclear Information System (INIS)

    Khani, F.; Hamedi-Nezhad, S.; Molabahrami, A.

    2007-01-01

    Exp-function method is used to find a unified solution of nonlinear wave equation. Nonlinear Schroedinger equations with cubic and power law nonlinearity are selected to illustrate the effectiveness and simplicity of the method. It is shown that the Exp-function method, with the help of symbolic computation, provides a powerful mathematical tool for solving nonlinear equation

  11. Identification of Nonlinear Dynamic Systems Possessing Some Non-linearities

    Directory of Open Access Journals (Sweden)

    Y. N. Pavlov

    2015-01-01

    Full Text Available The subject of this work is the problem of identification of nonlinear dynamic systems based on the experimental data obtained by applying test signals to the system. The goal is to determinate coefficients of differential equations of systems by experimental frequency hodographs and separate similar, but different, in essence, forces: dissipative forces with the square of the first derivative in the motion equations and dissipative force from the action of dry friction. There was a proposal to use the harmonic linearization method to approximate each of the nonlinearity of "quadratic friction" and "dry friction" by linear friction with the appropriate harmonic linearization coefficient.Assume that a frequency transfer function of the identified system has a known form. Assume as well that there are disturbances while obtaining frequency characteristics of the realworld system. As a result, the points of experimentally obtained hodograph move randomly. Searching for solution of the identification problem was in the hodograph class, specified by the system model, which has the form of the frequency transfer function the same as the form of the frequency transfer function of the system identified. Minimizing a proximity criterion (measure of the experimentally obtained system hodograph and the system hodograph model for all the experimental points described and previously published by one of the authors allowed searching for the unknown coefficients of the frequenc ransfer function of the system model. The paper shows the possibility to identify a nonlinear dynamic system with multiple nonlinearities, obtained on the experimental samples of the frequency system hodograph. The proposed algorithm allows to select the nonlinearity of the type "quadratic friction" and "dry friction", i.e. also in the case where the nonlinearity is dependent on the same dynamic parameter, in particular, on the derivative of the system output value. For the dynamic

  12. Final report. [Nonlinear magnetohydrodynamics

    International Nuclear Information System (INIS)

    Montgomery, D.C.

    1998-01-01

    This is a final report on the research activities carried out under the above grant at Dartmouth. During the period considered, the grant was identified as being for nonlinear magnetohydrodynamics, considered as the most tractable theoretical framework in which the plasma problems associated with magnetic confinement of fusion plasmas could be studied. During the first part of the grant's lifetime, the author was associated with Los Alamos National Laboratory as a consultant and the work was motivated by the reversed-field pinch. Later, when that program was killed at Los Alamos, the problems became ones that could be motivated by their relation to tokamaks. Throughout the work, the interest was always on questions that were as fundamental as possible, compatible with those motivations. The intent was always to contribute to plasma physics as a science, as well as to the understanding of mission-oriented confined fusion plasmas. Twelve Ph.D. theses were supervised during this period and a comparable number of postdoctoral research associates were temporarily supported. Many of these have gone on to distinguished careers, though few have done so in the context of the controlled fusion program. Their work was a combination of theory and numerical computation, in gradually less and less idealized settings, moving from rectangular periodic boundary conditions in two dimensions, through periodic straight cylinders and eventually, before the grant was withdrawn, to toroids, with a gradually more prominent role for electrical and mechanical boundary conditions. The author never had access to a situation where he could initiate experiments and relate directly to the laboratory data he wanted. Computers were the laboratory. Most of the work was reported in referred publications in the open literature, copies of which were transmitted one by one to DOE at the time they appeared. The Appendix to this report is a bibliography of published work which was carried out under the

  13. Animation with concurrent narration versus narration in physical education lesson

    Directory of Open Access Journals (Sweden)

    Ioannou Panagiotis

    2016-01-01

    Full Text Available The purpose of the present study was to compare the effects of two different teaching methods on students' comprehension during Physical Education lesson: narration versus animation with concurrent narration, during teaching shot put event. Thirty primary school children (boys and girls volunteered to participate in this study. In experiment students listened (narration and viewed (animation with narration the presentation of two shot putting styles. A problem-solving and a retention test were used to evaluate students' comprehension. Results showed that students' comprehension was better when shot putting styles were presented through a mixed model (animation and narration group than a single (narration. The animation with concurrent narration group performed better than the narration group, in problem-solving (M = 4.91, SD = 1.36 and in retention test (M = 5.98, SD = 1.28 t(28 = 1.89 p<0.01. An instructional implication is that pictures with words is more effective way of teaching when they occur continuingly in time, than only words during Physical Education lesson.

  14. Resource Management and Contingencies in Aerospace Concurrent Engineering

    Science.gov (United States)

    Karpati, Gabe; Hyde, Tupper; Peabody, Hume; Garrison, Matthew

    2012-01-01

    significant concern in designing complex systems implementing new technologies is that while knowledge about the system is acquired incrementally, substantial financial commitments, even make-or-break decisions, must be made upfront, essentially in the unknown. One practice that helps in dealing with this dichotomy is the smart embedding of contingencies and margins in the design to serve as buffers against surprises. This issue presents itself in full force in the aerospace industry, where unprecedented systems are formulated and committed to as a matter of routine. As more and more aerospace mission concepts are generated by concurrent design laboratories, it is imperative that such laboratories apply well thought-out contingency and margin structures to their designs. The first part of this publication provides an overview of resource management techniques and standards used in the aerospace industry. That is followed by a thought provoking treatise on margin policies. The expose presents the actual flight telemetry data recorded by the thermal discipline during several recent NASA Goddard Space Flight Center missions. The margins actually achieved in flight are compared against pre-flight predictions, and the appropriateness and the ramifications of having designed with rigid margins to bounding stacked worst case conditions are assessed. The second half of the paper examines the particular issues associated with the application of contingencies and margins in the concurrent engineering environment. In closure, a discipline-by-discipline disclosure of the contingency and margin policies in use at the Integrated Design Center at NASA s Goddard Space Flight Center is made.

  15. Sarcoidosis and multiple myeloma: Concurrent presentation of an unusual association

    Directory of Open Access Journals (Sweden)

    Vidya Nair

    2016-01-01

    Full Text Available Literature on concurrent association of sarcoidosis with lymphoproliferative malignancies other than lymphoma e.g. multiple myeloma is meager. The rarity of the situation prompted us to report this patient who was a 51-year-old woman with a 2-years history of breathlessness, cough with expectoration, chest pain and backache. Initial evaluation revealed mild anemia, increased alkaline phosphatase with chest skiagram showing both lower zone non homogenous opacities with calcified hilar lymph nodes. CECT chest showed mediastinal with bilateral hilar lymphadenopathy, parenchymal fibrosis, traction bronchiectasis, ground glass opacities, septal and peribronchovascular thickening affecting mid and lower lung zones bilaterally. MRI Dorsolumbar spine was suggestive of marrow infiltrative disorder. EBUS FNA of intrathoracic nodes, EBB and TBLB confirmed sarcoidosis. PET CT revealed hyper metabolic activity in lung, multiple lymph nodes and lytic bone lesions. Serum protein electrophoresis and immunofixation revealed a monoclonal paraprotein, immunoglobulin IgG kappa type. Bone marrow biopsy revealed an increase in plasma cells (15%, but no granulomas. Diagnosis of Indolent or multiple myeloma with sarcoidosis was established. 12 cases of sarcoidosis and multiple myeloma have been reported in literature, and mostly preceding the onset of multiple myeloma by many years, in our case both were diagnosed concurrently.

  16. Hickam's dictum: Myasthenia Gravis presenting concurrently with Graves' disease.

    Science.gov (United States)

    Sehgal, Shekhar; Rebello, Roshan; Wolmarans, Louise; Elston, Marianne

    2017-09-07

    We present two patients with Graves' disease and concurrent myasthenia gravis. The impact of the dual diagnosis on the clinical course and the potential for a delayed diagnosis of myasthenia gravis is discussed. Patient 1, a 28-year-old man was diagnosed with Graves' disease following his second respiratory arrest. His history was strongly suggestive of a second pathology. Patient 2, a 66-year-old Cantonese woman with established Graves' disease presented with thionamide-related neutropaenia. Examination revealed bilateral ptosis and right lateral rectus palsy. Both patients had thyrotoxicosis secondary to Graves' disease with concurrent myasthenia gravis. Although neuromuscular weakness is common in Graves' disease, coexisting myasthenia gravis (MG) is rare and can cause profound morbidity. Ocular signs in both diseases may cause diagnostic confusion although ptosis suggests coexisting MG. In both cases, the thyrotoxicosis delayed the diagnosis of MG. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  17. Retrospective Cost Adaptive Control with Concurrent Closed-Loop Identification

    Science.gov (United States)

    Sobolic, Frantisek M.

    Retrospective cost adaptive control (RCAC) is a discrete-time direct adaptive control algorithm for stabilization, command following, and disturbance rejection. RCAC is known to work on systems given minimal modeling information which is the leading numerator coefficient and any nonminimum-phase (NMP) zeros of the plant transfer function. This information is normally needed a priori and is key in the development of the filter, also known as the target model, within the retrospective performance variable. A novel approach to alleviate the need for prior modeling of both the leading coefficient of the plant transfer function as well as any NMP zeros is developed. The extension to the RCAC algorithm is the use of concurrent optimization of both the target model and the controller coefficients. Concurrent optimization of the target model and controller coefficients is a quadratic optimization problem in the target model and controller coefficients separately. However, this optimization problem is not convex as a joint function of both variables, and therefore nonconvex optimization methods are needed. Finally, insights within RCAC that include intercalated injection between the controller numerator and the denominator, unveil the workings of RCAC fitting a specific closed-loop transfer function to the target model. We exploit this interpretation by investigating several closed-loop identification architectures in order to extract this information for use in the target model.

  18. GLobal Integrated Design Environment (GLIDE): A Concurrent Engineering Application

    Science.gov (United States)

    McGuire, Melissa L.; Kunkel, Matthew R.; Smith, David A.

    2010-01-01

    The GLobal Integrated Design Environment (GLIDE) is a client-server software application purpose-built to mitigate issues associated with real time data sharing in concurrent engineering environments and to facilitate discipline-to-discipline interaction between multiple engineers and researchers. GLIDE is implemented in multiple programming languages utilizing standardized web protocols to enable secure parameter data sharing between engineers and researchers across the Internet in closed and/or widely distributed working environments. A well defined, HyperText Transfer Protocol (HTTP) based Application Programming Interface (API) to the GLIDE client/server environment enables users to interact with GLIDE, and each other, within common and familiar tools. One such common tool, Microsoft Excel (Microsoft Corporation), paired with its add-in API for GLIDE, is discussed in this paper. The top-level examples given demonstrate how this interface improves the efficiency of the design process of a concurrent engineering study while reducing potential errors associated with manually sharing information between study participants.

  19. Concurrent cardiovascular and resistance training in healthy older adults.

    Science.gov (United States)

    Wood, R H; Reyes, R; Welsch, M A; Favaloro-Sabatier, J; Sabatier, M; Matthew Lee, C; Johnson, L G; Hooper, P F

    2001-10-01

    The recommendations for exercise training and physical activity for older adults include cardiovascular and resistance training components (CVT and RT, respectively). The purpose of the present investigation was to compare the fitness benefits of concurrent CVT and RT with those attained through an equivalent duration of CVT or RT alone. Thirty-six participants (ages 60-84) were assigned to a control group or to one of three exercise treatment groups. The treatment groups exercised three times per week for 12 wk using RT (N = 11), CVT (N = 10), or CVT and RT (BOTH, N = 9). Pre- and post-training, participants performed a submaximal exercise test (GXT), five repetition-maximum strength tests (5RM), and the AAHPERD functional fitness test for older adults. All exercise treatment groups revealed lower resting heart rate and rate-pressure product; lower exercise diastolic blood pressure and rating of perceived exertion; increased GXT duration; increased leg, back, and shoulder 5RM scores; and improved AAHPERD flexibility, coordination, and cardiovascular endurance scores. The exercise treatment groups responded differently on the following: RT and BOTH enhanced arm and chest strength more than CVT; and BOTH enhanced AAHPERD strength and agility scores more than CVT or RT. Concurrent CVT and RT is as effective in eliciting improvements in cardiovascular fitness and 5RM performance as CVT or RT, respectively. Moreover, incorporating both CVT and RT in exercise programs for older adults may be more effective in optimizing aspects of functional fitness than programs that involve only one component.

  20. Foveal Processing Under Concurrent Peripheral Load in Profoundly Deaf Adults

    Science.gov (United States)

    2016-01-01

    Development of the visual system typically proceeds in concert with the development of audition. One result is that the visual system of profoundly deaf individuals differs from that of those with typical auditory systems. While past research has suggested deaf people have enhanced attention in the visual periphery, it is still unclear whether or not this enhancement entails deficits in central vision. Profoundly deaf and typically hearing adults were administered a variant of the useful field of view task that independently assessed performance on concurrent central and peripheral tasks. Identification of a foveated target was impaired by a concurrent selective peripheral attention task, more so in profoundly deaf adults than in the typically hearing. Previous findings of enhanced performance on the peripheral task were not replicated. These data are discussed in terms of flexible allocation of spatial attention targeted towards perceived task demands, and support a modified “division of labor” hypothesis whereby attentional resources co-opted to process peripheral space result in reduced resources in the central visual field. PMID:26657078

  1. Concurrent Bursty Behavior of Social Sensors in Sporting Events

    Science.gov (United States)

    Takeichi, Yuki; Sasahara, Kazutoshi; Suzuki, Reiji; Arita, Takaya

    2015-01-01

    The advent of social media expands our ability to transmit information and connect with others instantly, which enables us to behave as “social sensors.” Here, we studied concurrent bursty behavior of Twitter users during major sporting events to determine their function as social sensors. We show that the degree of concurrent bursts in tweets (posts) and retweets (re-posts) works as a strong indicator of winning or losing a game. More specifically, our simple tweet analysis of Japanese professional baseball games in 2013 revealed that social sensors can immediately react to positive and negative events through bursts of tweets, but that positive events are more likely to induce a subsequent burst of retweets. We confirm that these findings also hold true for tweets related to Major League Baseball games in 2015. Furthermore, we demonstrate active interactions among social sensors by constructing retweet networks during a baseball game. The resulting networks commonly exhibited user clusters depending on the baseball team, with a scale-free connectedness that is indicative of a substantial difference in user popularity as an information source. While previous studies have mainly focused on bursts of tweets as a simple indicator of a real-world event, the temporal correlation between tweets and retweets implies unique aspects of social sensors, offering new insights into human behavior in a highly connected world. PMID:26659028

  2. Epidemiology of concurrent headache and sleep problems in Denmark.

    Science.gov (United States)

    Lund, Nunu; Westergaard, Maria Lurenda; Barloese, Mads; Glümer, Charlotte; Jensen, Rigmor Højland

    2014-09-01

    There are no previous epidemiologic studies on concurrent headache and sleep problems (HSP). This cross-sectional study aimed to determine the prevalence of HSP in Denmark, broadly characterize those with HSP, and examine associations between HSP and socioeconomic/lifestyle factors. A total of 129,150 randomly selected individuals were invited to participate in the Danish National Health Survey 2010. Respondents were asked about headache, sleep problems, depression and anxiety in the last two weeks, health-related lifestyle and quality of life (SF-12). Socioeconomic data were retrieved from national registers. Prevalence proportions were adjusted for stratified sampling and non-response. Regression analyses examined associations between HSP and socioeconomic/lifestyle factors. Of 68,518 respondents, 16.3% reported only headache, 21.1% only sleep problems, and 18.1% HSP with 2.6% being severely affected. Prevalence was higher among women and the middle-aged. Severe HSP was associated with low socioeconomic position, non-Western ethnicity, unhealthy lifestyle, high stress and anxiety/depression. Those with HSP had substantially reduced quality of life; more so than those having only headache or only sleep problems. HSP is a highly prevalent condition. Lifestyle modification, stress reduction, and screening for concurrent depression and anxiety may play important roles in management. The high prevalence of HSP suggests a common pathophysiological mechanism. © International Headache Society 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

  3. Channels as Objects in Concurrent Object-Oriented Programming

    Directory of Open Access Journals (Sweden)

    Joana Campos

    2011-10-01

    Full Text Available There is often a sort of a protocol associated to each class, stating when and how certain methods should be called. Given that this protocol is, if at all, described in the documentation accompanying the class, current mainstream object-oriented languages cannot provide for the verification of client code adherence against the sought class behaviour. We have defined a class-based concurrent object-oriented language that formalises such protocols in the form of usage types. Usage types are attached to class definitions, allowing for the specification of (1 the available methods, (2 the tests clients must perform on the result of methods, and (3 the object status - linear or shared - all of which depend on the object's state. Our work extends the recent approach on modular session types by eliminating channel operations, and defining the method call as the single communication primitive in both sequential and concurrent settings. In contrast to previous works, we define a single category for objects, instead of distinct categories for linear and for shared objects, and let linear objects evolve into shared ones. We introduce a standard sync qualifier to prevent thread interference in certain operations on shared objects. We formalise the language syntax, the operational semantics, and a type system that enforces by static typing that methods are called only when available, and by a single client if so specified in the usage type. We illustrate the language via a complete example.

  4. Cross Functional Working and Concurrent Engineering – a UK Study

    Directory of Open Access Journals (Sweden)

    H. Williams

    2000-01-01

    Full Text Available This paper reports on the preliminary results of an investigative study into the implementation of concurrent engineering applied to new product development. Concurrent (or Simultaneous engineering is the term commonly given to creating new products using multi-disciplined teams of marketing, design, manufacturing and support functions together with supplier and customers. Such techniques have produced robust, low cost quality products in short concept to market times compared to traditional ones. The research investigated design management practice and performance in a number of organisations across a range of industrial sectors in the UK by means of a questionnaire survey. The results identify the current use of a variety of design practices and methodologies such as different organisational structures, the extent of cross-functional working, the use of design and phase reviews and the use of different technologies. They indicate that companies implementing CE are more successful in time to market performance than those who don’t implement CE. Factors most influencing the successful adoption of CE are design and phase reviews, and, to a lesser extent, the use of multifunctional teams and supplier partnerships.

  5. Model-Based Systems Engineering in Concurrent Engineering Centers

    Science.gov (United States)

    Iwata, Curtis; Infeld, Samantha; Bracken, Jennifer Medlin; McGuire, Melissa; McQuirk, Christina; Kisdi, Aron; Murphy, Jonathan; Cole, Bjorn; Zarifian, Pezhman

    2015-01-01

    Concurrent Engineering Centers (CECs) are specialized facilities with a goal of generating and maturing engineering designs by enabling rapid design iterations. This is accomplished by co-locating a team of experts (either physically or virtually) in a room with a narrow design goal and a limited timeline of a week or less. The systems engineer uses a model of the system to capture the relevant interfaces and manage the overall architecture. A single model that integrates other design information and modeling allows the entire team to visualize the concurrent activity and identify conflicts more efficiently, potentially resulting in a systems model that will continue to be used throughout the project lifecycle. Performing systems engineering using such a system model is the definition of model-based systems engineering (MBSE); therefore, CECs evolving their approach to incorporate advances in MBSE are more successful in reducing time and cost needed to meet study goals. This paper surveys space mission CECs that are in the middle of this evolution, and the authors share their experiences in order to promote discussion within the community.

  6. Complex motions and chaos in nonlinear systems

    CERN Document Server

    Machado, José; Zhang, Jiazhong

    2016-01-01

    This book brings together 10 chapters on a new stream of research examining complex phenomena in nonlinear systems—including engineering, physics, and social science. Complex Motions and Chaos in Nonlinear Systems provides readers a particular vantage of the nature and nonlinear phenomena in nonlinear dynamics that can develop the corresponding mathematical theory and apply nonlinear design to practical engineering as well as the study of other complex phenomena including those investigated within social science.

  7. Cascaded nonlinearities for ultrafast nonlinear optical science and applications

    DEFF Research Database (Denmark)

    Bache, Morten

    the cascading nonlinearity is investigated in detail, especially with focus on femtosecond energetic laser pulses being subjected to this nonlinear response. Analytical, numerical and experimental results are used to understand the cascading interaction and applications are demonstrated. The defocusing soliton...... observations with analogies in fiber optics are observed numerically and experimentally, including soliton self-compression, soliton-induced resonant radiation, supercontinuum generation, optical wavebreaking and shock-front formation. All this happens despite no waveguide being present, thanks...... is of particular interest here, since it is quite unique and provides the solution to a number of standing challenges in the ultrafast nonlinear optics community. It solves the problem of catastrophic focusing and formation of a filaments in bulk glasses, which even under controlled circumstances is limited...

  8. Input saturation in nonlinear multivariable processes resolved by nonlinear decoupling

    Directory of Open Access Journals (Sweden)

    Jens G. Balchen

    1995-04-01

    Full Text Available A new method is presented for the resolution of the problem of input saturation in nonlinear multivariable process control by means of elementary nonlinear decoupling (END. Input saturation can have serious consequences particularly in multivariable control because it may lead to very undesirable system behaviour and quite often system instability. Many authors have searched for systematic techniques for designing multivariable control systems in which saturation may occur in any of the control variables (inputs, manipulated variables. No generally accepted method seems to have been presented so far which gives a solution in closed form. The method of elementary nonlinear decoupling (END can be applied directly to the case of saturation control variables by deriving as many control strategies as there are combinations of saturating control variables. The method is demonstrated by the multivariable control of a simulated Fluidized Catalytic Cracker (FCC with very convincing results.

  9. Nonlinear analysis of pupillary dynamics.

    Science.gov (United States)

    Onorati, Francesco; Mainardi, Luca Tommaso; Sirca, Fabiola; Russo, Vincenzo; Barbieri, Riccardo

    2016-02-01

    Pupil size reflects autonomic response to different environmental and behavioral stimuli, and its dynamics have been linked to other autonomic correlates such as cardiac and respiratory rhythms. The aim of this study is to assess the nonlinear characteristics of pupil size of 25 normal subjects who participated in a psychophysiological experimental protocol with four experimental conditions, namely “baseline”, “anger”, “joy”, and “sadness”. Nonlinear measures, such as sample entropy, correlation dimension, and largest Lyapunov exponent, were computed on reconstructed signals of spontaneous fluctuations of pupil dilation. Nonparametric statistical tests were performed on surrogate data to verify that the nonlinear measures are an intrinsic characteristic of the signals. We then developed and applied a piecewise linear regression model to detrended fluctuation analysis (DFA). Two joinpoints and three scaling intervals were identified: slope α0, at slow time scales, represents a persistent nonstationary long-range correlation, whereas α1 and α2, at middle and fast time scales, respectively, represent long-range power-law correlations, similarly to DFA applied to heart rate variability signals. Of the computed complexity measures, α0 showed statistically significant differences among experimental conditions (pnonlinear dynamics, (b) three well-defined and distinct long-memory processes exist at different time scales, and (c) autonomic stimulation is partially reflected in nonlinear dynamics. (c) autonomic stimulation is partially reflected in nonlinear dynamics.

  10. Introduction to nonlinear dispersive equations

    CERN Document Server

    Linares, Felipe

    2015-01-01

    This textbook introduces the well-posedness theory for initial-value problems of nonlinear, dispersive partial differential equations, with special focus on two key models, the Korteweg–de Vries equation and the nonlinear Schrödinger equation. A concise and self-contained treatment of background material (the Fourier transform, interpolation theory, Sobolev spaces, and the linear Schrödinger equation) prepares the reader to understand the main topics covered: the initial-value problem for the nonlinear Schrödinger equation and the generalized Korteweg–de Vries equation, properties of their solutions, and a survey of general classes of nonlinear dispersive equations of physical and mathematical significance. Each chapter ends with an expert account of recent developments and open problems, as well as exercises. The final chapter gives a detailed exposition of local well-posedness for the nonlinear Schrödinger equation, taking the reader to the forefront of recent research. The second edition of Introdu...

  11. Concurrent sexual partnerships among African American women in Philadelphia: results from a qualitative study.

    Science.gov (United States)

    Nunn, Amy; Dickman, Samuel; Cornwall, Alexandra; Kwakwa, Helena; Mayer, Kenneth H; Rana, Aadia; Rosengard, Cynthia

    2012-07-01

    African American women are disproportionately affected by HIV/AIDS. Concurrent sexual partnerships may contribute to racial disparities in HIV infection. Little is known about attitudes and practices related to concurrency among African American women, or the social, structural and behavioural factors influencing concurrency. We recruited 19 heterosexual African American women engaging in concurrent sexual partnerships from a public clinic in Philadelphia in 2009. We conducted interviews exploring social norms, attitudes and practices about concurrency, and the structural, social and behavioural factors influencing concurrent sexual partnerships, guided by grounded theory. Seventeen women reported one main and one or more non-main partners; two reported no main partners. Many women used condoms more frequently with non-main than main partners, noting they trust main partners more than non-main partners. Social factors included social normalisation of concurrency, inability to negotiate partners' concurrent partnerships, being unmarried, and not trusting partners. Lack of trust was the most commonly cited reason that women engaged in concurrent partnerships. Structural factors included economic dependence on partners, partners' dependence on women for economic support and incarceration that interrupted partnerships. Behavioural factors included alcohol and cocaine use. Social, structural and behavioural factors strongly influenced these African American women's concurrent sexual partnerships. Many HIV interventions disseminated by the CDC focus largely on behavioural factors and may fail to address the social and structural factors influencing African American women's sexual networks. Novel HIV prevention interventions that address the social determinants of African American women's HIV risks are urgently needed.

  12. Three-terminal ferroelectric synapse device with concurrent learning function for artificial neural networks

    International Nuclear Information System (INIS)

    Nishitani, Y.; Kaneko, Y.; Ueda, M.; Fujii, E.; Morie, T.

    2012-01-01

    Spike-timing-dependent synaptic plasticity (STDP) is demonstrated in a synapse device based on a ferroelectric-gate field-effect transistor (FeFET). STDP is a key of the learning functions observed in human brains, where the synaptic weight changes only depending on the spike timing of the pre- and post-neurons. The FeFET is composed of the stacked oxide materials with ZnO/Pr(Zr,Ti)O 3 (PZT)/SrRuO 3 . In the FeFET, the channel conductance can be altered depending on the density of electrons induced by the polarization of PZT film, which can be controlled by applying the gate voltage in a non-volatile manner. Applying a pulse gate voltage enables the multi-valued modulation of the conductance, which is expected to be caused by a change in PZT polarization. This variation depends on the height and the duration of the pulse gate voltage. Utilizing these characteristics, symmetric and asymmetric STDP learning functions are successfully implemented in the FeFET-based synapse device by applying the non-linear pulse gate voltage generated from a set of two pulses in a sampling circuit, in which the two pulses correspond to the spikes from the pre- and post-neurons. The three-terminal structure of the synapse device enables the concurrent learning, in which the weight update can be performed without canceling signal transmission among neurons, while the neural networks using the previously reported two-terminal synapse devices need to stop signal transmission for learning.

  13. Nonlinear dynamics in biological systems

    CERN Document Server

    Carballido-Landeira, Jorge

    2016-01-01

    This book presents recent research results relating to applications of nonlinear dynamics, focusing specifically on four topics of wide interest: heart dynamics, DNA/RNA, cell mobility, and proteins. The book derives from the First BCAM Workshop on Nonlinear Dynamics in Biological Systems, held in June 2014 at the Basque Center of Applied Mathematics (BCAM). At this international meeting, researchers from different but complementary backgrounds, including molecular dynamics, physical chemistry, bio-informatics and biophysics, presented their most recent results and discussed the future direction of their studies using theoretical, mathematical modeling and experimental approaches. Such was the level of interest stimulated that the decision was taken to produce this publication, with the organizers of the event acting as editors. All of the contributing authors are researchers working on diverse biological problems that can be approached using nonlinear dynamics. The book will appeal especially to applied math...

  14. Neoclassical transport including collisional nonlinearity.

    Science.gov (United States)

    Candy, J; Belli, E A

    2011-06-10

    In the standard δf theory of neoclassical transport, the zeroth-order (Maxwellian) solution is obtained analytically via the solution of a nonlinear equation. The first-order correction δf is subsequently computed as the solution of a linear, inhomogeneous equation that includes the linearized Fokker-Planck collision operator. This equation admits analytic solutions only in extreme asymptotic limits (banana, plateau, Pfirsch-Schlüter), and so must be solved numerically for realistic plasma parameters. Recently, numerical codes have appeared which attempt to compute the total distribution f more accurately than in the standard ordering by retaining some nonlinear terms related to finite-orbit width, while simultaneously reusing some form of the linearized collision operator. In this work we show that higher-order corrections to the distribution function may be unphysical if collisional nonlinearities are ignored.

  15. Nonlinear photoacoustic spectroscopy of hemoglobin.

    Science.gov (United States)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P; Xia, Jun; Wang, Lihong V

    2015-05-18

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.

  16. Nonlinear photoacoustic spectroscopy of hemoglobin

    International Nuclear Information System (INIS)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P.; Xia, Jun; Wang, Lihong V.

    2015-01-01

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography

  17. Nonlinear Deformable-body Dynamics

    CERN Document Server

    Luo, Albert C J

    2010-01-01

    "Nonlinear Deformable-body Dynamics" mainly consists in a mathematical treatise of approximate theories for thin deformable bodies, including cables, beams, rods, webs, membranes, plates, and shells. The intent of the book is to stimulate more research in the area of nonlinear deformable-body dynamics not only because of the unsolved theoretical puzzles it presents but also because of its wide spectrum of applications. For instance, the theories for soft webs and rod-reinforced soft structures can be applied to biomechanics for DNA and living tissues, and the nonlinear theory of deformable bodies, based on the Kirchhoff assumptions, is a special case discussed. This book can serve as a reference work for researchers and a textbook for senior and postgraduate students in physics, mathematics, engineering and biophysics. Dr. Albert C.J. Luo is a Professor of Mechanical Engineering at Southern Illinois University, Edwardsville, IL, USA. Professor Luo is an internationally recognized scientist in the field of non...

  18. NONLINEAR DYNAMICS OF ORGANIZATION DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    Денис Антонович БУШУЕВ

    2016-02-01

    Full Text Available The nonlinear behavior of organizations in development projects is considered. The nonlinear behavior is initiated in the growth of organizations and requires a restructuring of governance in identifying dysfunctions. Such a restructuring is needed in the area of soft components, determining the organizational levels of competence in the management of projects, programs, portfolios and heads of the Project Management Office. An important component of the strategic development of the organization is the proposed concept for formation and management of development programs in the context according to their life cycle. It should take into account the non-linear behavior of the soft components of the system and violation of functional processes of the organization. The specific management syndromes of projects and programs are considered. Such as syndromes time management project linked to the singular points of the project. These syndromes are "shift to the right", "point of no return", "braking at the end of the project" and others.

  19. Nonlinear operators and their propagators

    International Nuclear Information System (INIS)

    Schwartz, C.

    1997-01-01

    Mathematical physicists are familiar with a large set of tools designed for dealing with linear operators, which are so common in both the classical and quantum theories; but many of those tools are useless with nonlinear equations of motion. In this work a general algebra and calculus is developed for working with nonlinear operators: The basic new tool being the open-quotes slash product,close quotes defined by A(1+εB) =A+εA/B+O(ε 2 ). For a generic time development equation, the propagator is constructed and then there follows the formal version of time dependent perturbation theory, in remarkable similarity to the linear situation. A nonperturbative approximation scheme capable of producing high accuracy computations, previously developed for linear operators, is shown to be applicable as well in the nonlinear domain. A number of auxiliary mathematical properties and examples are given. copyright 1997 American Institute of Physics

  20. Nonlinear optics an analytical approach

    CERN Document Server

    Mandel, Paul

    2010-01-01

    Based on the author's extensive teaching experience and lecture notes, this textbook provides a substantially analytical rather than descriptive presentation of nonlinear optics. Divided into five parts, with most chapters corresponding to a two-hour lecture, the book begins with a unique account of the historical development from Kirchhoff's law for the black-body radiation to Planck's quantum hypothesis and Einstein's discovery of spontaneous emission - providing all the explicit proofs. The subsequent sections deal with matter quantization, ultrashort pulse propagation in 2-level media, cavity nonlinear optics, chi(2) and chi(3) media. For graduate and PhD students in nonlinear optics or photonics, while also representing a valuable reference for researchers in these fields.

  1. Nonlinear photoacoustic spectroscopy of hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Danielli, Amos; Maslov, Konstantin; Favazza, Christopher P.; Xia, Jun; Wang, Lihong V., E-mail: LHWANG@WUSTL.EDU [Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, Missouri 63130 (United States)

    2015-05-18

    As light intensity increases in photoacoustic imaging, the saturation of optical absorption and the temperature dependence of the thermal expansion coefficient result in a measurable nonlinear dependence of the photoacoustic (PA) signal on the excitation pulse fluence. Here, under controlled conditions, we investigate the intensity-dependent photoacoustic signals from oxygenated and deoxygenated hemoglobin at varied optical wavelengths and molecular concentrations. The wavelength and concentration dependencies of the nonlinear PA spectrum are found to be significantly greater in oxygenated hemoglobin than in deoxygenated hemoglobin. These effects are further influenced by the hemoglobin concentration. These nonlinear phenomena provide insights into applications of photoacoustics, such as measurements of average inter-molecular distances on a nm scale or with a tuned selection of wavelengths, a more accurate quantitative PA tomography.

  2. Optimization for nonlinear inverse problem

    International Nuclear Information System (INIS)

    Boyadzhiev, G.; Brandmayr, E.; Pinat, T.; Panza, G.F.

    2007-06-01

    The nonlinear inversion of geophysical data in general does not yield a unique solution, but a single model, representing the investigated field, is preferred for an easy geological interpretation of the observations. The analyzed region is constituted by a number of sub-regions where the multi-valued nonlinear inversion is applied, which leads to a multi-valued solution. Therefore, combining the values of the solution in each sub-region, many acceptable models are obtained for the entire region and this complicates the geological interpretation of geophysical investigations. In this paper are presented new methodologies, capable to select one model, among all acceptable ones, that satisfies different criteria of smoothness in the explored space of solutions. In this work we focus on the non-linear inversion of surface waves dispersion curves, which gives structural models of shear-wave velocity versus depth, but the basic concepts have a general validity. (author)

  3. Nonlinear elasticity in resonance experiments

    Science.gov (United States)

    Li, Xun; Sens-Schönfelder, Christoph; Snieder, Roel

    2018-04-01

    Resonant bar experiments have revealed that dynamic deformation induces nonlinearity in rocks. These experiments produce resonance curves that represent the response amplitude as a function of the driving frequency. We propose a model to reproduce the resonance curves with observed features that include (a) the log-time recovery of the resonant frequency after the deformation ends (slow dynamics), (b) the asymmetry in the direction of the driving frequency, (c) the difference between resonance curves with the driving frequency that is swept upward and downward, and (d) the presence of a "cliff" segment to the left of the resonant peak under the condition of strong nonlinearity. The model is based on a feedback cycle where the effect of softening (nonlinearity) feeds back to the deformation. This model provides a unified interpretation of both the nonlinearity and slow dynamics in resonance experiments. We further show that the asymmetry of the resonance curve is caused by the softening, which is documented by the decrease of the resonant frequency during the deformation; the cliff segment of the resonance curve is linked to a bifurcation that involves a steep change of the response amplitude when the driving frequency is changed. With weak nonlinearity, the difference between the upward- and downward-sweeping curves depends on slow dynamics; a sufficiently slow frequency sweep eliminates this up-down difference. With strong nonlinearity, the up-down difference results from both the slow dynamics and bifurcation; however, the presence of the bifurcation maintains the respective part of the up-down difference, regardless of the sweep rate.

  4. An unusual case of concurrent insulinoma and nesidioblastosis.

    Science.gov (United States)

    Bright, Elizabeth; Garcea, Giuseppe; Ong, Seok L; Madira, Webster; Berry, David P; Dennison, Ashley R

    2008-09-02

    Endogenous hyperinsulinaemic hypoglycaemia in adults is most commonly caused by an insulinoma. Adult nesidioblastosis is rarely reported. To the best of our knowledge the presence of both insulinoma and nesidioblastosis has not been reported before. We report a case of a 35-year-old female presenting with neuroglycaemic symptoms. A supervised 72-hour fast confirmed hypoglycaemia in the presence of hyperinsulinaemia. Thorough pre-operative biochemical and radiological investigations, including selective splenic, superior mesenteric and portal venous sampling inferred a tentative diagnosis of adult nesidioblastosis. However, a grossly elevated insulin level within the splenic vein on a second set of venous sampling produced a high index of suspicion for the presence of an insulinoma. At surgical exploration both an insulinoma and nesidioblastosis were identified and confirmed by histological examination. We report an even rarer entity of concurrent insulinoma and nesidioblastosis.

  5. Study on the concurrent calculation with a multitransputer network

    International Nuclear Information System (INIS)

    Inomata, Shinji; Suzuki, Katsuo

    1992-06-01

    A relation between the calculation processing time and the overhead of multitransputer network is studied in performing several concurrent calculations. Hardware configuration we used was a ring-type linked nine transputer network on an INMOS B008 mother board which was inserted into a slot of a personal computer compatible with IBM PC/AT. Further we used the occam2 toolset of MS-DOS version to write the calculation programs in the occam2 language. On arithmetic operations, some trigonometric and transcendental functions and numerical integrations, the calculation time and overhead were measured. The results show that the relative calculation speed is proportional to the number of transputers when the ratio of calculation time to overhead is much greater than 1.0. And the overhead is consumed in inter-communicating among transputers for the parallel calculation set-up. (author)

  6. Epidemiology of concurrent headache and sleep problems in Denmark

    DEFF Research Database (Denmark)

    Lund, Nunu; Westergaard, Maria Lurenda; Barloese, Mads

    2014-01-01

    with 2.6% being severely affected. Prevalence was higher among women and the middle-aged. Severe HSP was associated with low socioeconomic position, non-Western ethnicity, unhealthy lifestyle, high stress and anxiety/depression. Those with HSP had substantially reduced quality of life; more so than those......AIMS: There are no previous epidemiologic studies on concurrent headache and sleep problems (HSP). This cross-sectional study aimed to determine the prevalence of HSP in Denmark, broadly characterize those with HSP, and examine associations between HSP and socioeconomic/lifestyle factors. METHODS......: A total of 129,150 randomly selected individuals were invited to participate in the Danish National Health Survey 2010. Respondents were asked about headache, sleep problems, depression and anxiety in the last two weeks, health-related lifestyle and quality of life (SF-12). Socioeconomic data were...

  7. Visualization of independence and dependence for program concurrency

    International Nuclear Information System (INIS)

    Belady, L.A.; Hosokawa, K.

    1984-01-01

    In order to fully utilize the CRT device's dynamic and two dimensional capabilities, a new way of thinking about programs and an associated notation are proposed. The scheme permits the explicit indication of the program's potential for parallel execution. The image created by the programmer on the screen provides the compiler with sequencing and concurrency information, while at the same time serves as a visual feedback to the programmer. So far the way of programming in two dimensions is just an idea and has not yet been tried either on a real life problem or by employing real life programmers. The authors are attempting a quick implementation in the form of a front end to an existing language

  8. A Tutorial on Parallel and Concurrent Programming in Haskell

    Science.gov (United States)

    Peyton Jones, Simon; Singh, Satnam

    This practical tutorial introduces the features available in Haskell for writing parallel and concurrent programs. We first describe how to write semi-explicit parallel programs by using annotations to express opportunities for parallelism and to help control the granularity of parallelism for effective execution on modern operating systems and processors. We then describe the mechanisms provided by Haskell for writing explicitly parallel programs with a focus on the use of software transactional memory to help share information between threads. Finally, we show how nested data parallelism can be used to write deterministically parallel programs which allows programmers to use rich data types in data parallel programs which are automatically transformed into flat data parallel versions for efficient execution on multi-core processors.

  9. Robust Concurrent Remote Entanglement Between Two Superconducting Qubits

    Directory of Open Access Journals (Sweden)

    A. Narla

    2016-09-01

    Full Text Available Entangling two remote quantum systems that never interact directly is an essential primitive in quantum information science and forms the basis for the modular architecture of quantum computing. When protocols to generate these remote entangled pairs rely on using traveling single-photon states as carriers of quantum information, they can be made robust to photon losses, unlike schemes that rely on continuous variable states. However, efficiently detecting single photons is challenging in the domain of superconducting quantum circuits because of the low energy of microwave quanta. Here, we report the realization of a robust form of concurrent remote entanglement based on a novel microwave photon detector implemented in the superconducting circuit quantum electrodynamics platform of quantum information. Remote entangled pairs with a fidelity of 0.57±0.01 are generated at 200 Hz. Our experiment opens the way for the implementation of the modular architecture of quantum computation with superconducting qubits.

  10. An Introduction to Parallelism, Concurrency and Acceleration (1/2)

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Concurrency and parallelism are firm elements of any modern computing infrastructure, made even more prominent by the emergence of accelerators. These lectures offer an introduction to these important concepts. We will begin with a brief refresher of recent hardware offerings to modern-day programmers. We will then open the main discussion with an overview of the laws and practical aspects of scalability. Key parallelism data structures, patterns and algorithms will be shown. The main threats to scalability and mitigation strategies will be discussed in the context of real-life optimization problems. Lecturer's short bio: Andrzej Nowak has 10 years of experience in computing technologies, primarily from CERN openlab and Intel. At CERN, he managed a research lab collaborating with Intel and was part of the openlab Chief Technology Office. Andrzej also worked closely and initiated projects with the private sector (e.g. HP and Google), as well as international research institutes, such as EPFL. Current...

  11. Concurrent chemoradiotherapy for advanced cervical cancer. A pilot study

    International Nuclear Information System (INIS)

    Kodama, Junichi; Hashimoto, Ichiro; Seki, Noriko; Hongo, Atsushi; Mizutani, Yasushi; Miyagi, Yasunari; Yoshinouchi, Mitsuo; Kudo, Takafumi

    2001-01-01

    Recently, attempts have made to use radiotherapy in combination with chemotherapy in various solid tumors including cervical cancer. Twenty-four patients with locally advanced cervical cancer were treated with concurrent Carboplatin (16-24 mg/m 2 /day) or Nedaplatin (20 mg/m 2 /week) and conventional radiotherapy. Of 13 evaluable patients, there were nine complete responders and four partial responders. There was no renal damage or grade 4 hematological toxicity. Gastrointestinal adverse reactions were mild. One patient had grade 3 dermatologic toxicity after delayed radiation therapy. This pilot study suggests that daily Carboplatin or weekly Nedaplatin administered with standard radiation therapy is safe, well-tolerated, and thus may be useful as a radiation sensitizer in the treatment of locally advanced cervical cancer. (author)

  12. MACHINE PROTECTION SYSTEM FOR CONCURRENT OPERATION OF RHIC AND BLIP

    International Nuclear Information System (INIS)

    WILINSKI, M.; BELLAVIA, S.; GLENN, J.W.; MAUSNER, L.F.; UNGER, K.L.

    2005-01-01

    The Brookhaven 200MeV linac is a multipurpose machine used to inject low intensity polarized protons for RHIC (Relativistic Heavy Ion Collider), as well as to inject high intensity protons to BLIP (Brookhaven Linac Isotope Producer), a medical isotope production facility. If high intensity protons were injected to RHIC by mistake, administrative radiation limits could be exceeded or sensitive electronics could be damaged. In the past, the changeover from polarized proton to high intensity proton operation has been a lengthy process, thereby never allowing the two programs to run simultaneously. To remedy this situation and allow concurrent operation of RHIC and BLIP, an active interlock system has been designed to monitor current levels in the AGS using two current transformers with fail safe circuitry and associated electronics to inhibit beam to RHIC if high intensity currents are detected

  13. Machine Protection System for Concurrent Operation of RHIC and BLIP

    CERN Document Server

    Wilinski, Michelle; Glenn, Joseph; Mausner, Leonard; Unger, Kerry

    2005-01-01

    The Brookhaven 200 MeV linac is a multipurpose machine used to inject low intensity polarized protons ultimately ending up in RHIC as well as to inject high intensity protons to BLIP, a medical isotope production facility. If high intensity protons were injected to RHIC by mistake, administrative radiation limits could be exceeded or sensitive electronics could be damaged. In the past, the changeover from polarized proton to high intensity proton operation has been a lengthy process, thereby never allowing the two programs to run simultaneously. To remedy this situation and allow for concurrent operation of RHIC and BLIP, an active interlock system has been designed to monitor current levels in the AGS using two current transformers with fail safe circuitry and associated electronics to inhibit beam to RHIC if high intensity is detected.

  14. An algebraic approach to analysis of recursive and concurrent programs

    DEFF Research Database (Denmark)

    Terepeta, Michal Tomasz

    -approximation of (or induced from) another flow algebra. Furthermore, we show how flow algebras can be used in communicating or weighted pushdown systems. To achieve that, we show that it is possible to relax some of the requirements imposed by original formulation of those techniques without compromising...... such a language. We also introduce an abstract domain that symbolically represents the messages sent between the concurrently executing processes. It stores prefixes or suffixes of communication traces including various constraints imposed on the messages. Since the problem has exponential complexity, we also...... present a compact data structure as well as efficient algorithms for the semiring operations. Apart from that, we discuss an improvement to Pre* and Post* algorithms for pushdown systems, making it possible to directly use program representations such as program graphs. We present a modular library...

  15. Fine-grained Information Flow for Concurrent Computation

    DEFF Research Database (Denmark)

    Li, Ximeng

    and reference monitors, have been proposed in the context of programming languages and process calculi, to enforce such properties. The most widely used definitions of information flow security are noninterference-like properties. For concurrent systems where processes communicate with each other to accomplish...... computational tasks, fine-grained security policies can be formulated by distinguishing between whether communication can happen, and what is communicated. As the first contribution of this PhD thesis, we formulate a noninterference-like property that takes all combinations of sensitivity levels for “whether...... to a classical one when the two dimensions are intentionally blurred. As the second contribution, we focus on the “what” dimension and further allow the flow policy to vary under different contents stored and communicated. This is the area of content-dependent (or conditional) information flow, which has...

  16. Salvage surgery for lymph node metastasis after concurrent chemoradiotherapy

    International Nuclear Information System (INIS)

    Kataoka, Hideyuki; Takeuchi, Eiji; Kawamoto, Katsuyuki; Fujiwara, Kazunori; Fukuhara, Takahiro; Miyake, Naritomo; Kitano, Hiroya

    2009-01-01

    Concurrent chemoradiation (CCRT) for advanced head and neck cancer is becoming more widely used. CCRT represents an effective treatment for patients with advanced head and neck cancer, and possibly improves survival. In the present study, all of 25 patients underwent planned neck dissection 6-8 weeks after the completion of radiation. Selective neck dissection was performed whenever possible. Radical neck dissection was carried out for patients with residual adenopathy that had invaded the surrounding structures and/or enclosed the carotid arteries. A complete response at the primary sites was achieved in all patients. Of the 25 cases, 7 (28%) showed viable cancer cells within their neck dissection specimens. Local and regional disease control was excellent after CCRT with neck dissection. Unfortunately, CCRT followed by neck dissection sometimes induces stomal infection and swallowing dysfunction. We have been performing additional surgery to improve the swallowing function and bilateral neck dissection simultaneously. (author)

  17. Swallowing rehabilitation before and during concurrent chemoradiotherapy for oropharyngeal cancer

    International Nuclear Information System (INIS)

    Tsuneyuki, Miki; Yonezawa, Kouichiro; Morimoto, Koichi; Tanimoto, Hitoshi; Saito, Miki; Otsuki, Naoki; Nibu, Ken-ichi

    2011-01-01

    Recently, oropharyngeal cancer is more frequently being managed with concurrent chemoradiotherapy (CCRT). As more patients receive CCRT, there is increasing attention on dysphagia. Since 2009, speech therapists in our hospital have performed swallowing rehabilitation for dysphagia associated with CCRT. We evaluated dysphagia after CCRT and examined the relationship between swallowing rehabilitation and swallowing disability. A total of 26 patients (22 males and 4 females) with a mean age of 63 years (range, 41 to 79), underwent CCRT between March 2008 and March 2010. Dysphagia after treatment was graded at the end of CCRT and discharge according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0 and Fujishima dysphagia grade. Ten of the 26 patients underwent swallowing rehabilitation, exercise and education on muscle strengthening programs before and during CCRT. They tended not to have severe dysphagia, but there were no significant differences. (author)

  18. TRENDS IN PRODUCT DEVELOPMENT: CONCURRENT ENGINEERING AND MECHATRONICS

    Directory of Open Access Journals (Sweden)

    Stefan IANCU

    2013-05-01

    Full Text Available This paper presents the most significant contemporary trends in new industrial product development:concurrent engineering (CE and mechatronics (M. Author defines what CE and M are, emphasizing whatconnections are between these two concepts, and which are the ways of integration in CE and M. The mainconclusion of this paper is that both these two concepts have known a strongly development in 1975-1985’s,when Information and Communication Technologies (ICT was in full swing of development. The influence ofICT is undoubted, but, from this point of view, there are differences: if M could not be implemented in theabsence of the ICT, communication and computational technologies are not strictly necessary for theimplementation of CE.

  19. Concurrent, parallel, multiphysics coupling in the FACETS project

    Energy Technology Data Exchange (ETDEWEB)

    Cary, J R; Carlsson, J A; Hakim, A H; Kruger, S E; Miah, M; Pletzer, A; Shasharina, S [Tech-X Corporation, 5621 Arapahoe Avenue, Suite A, Boulder, CO 80303 (United States); Candy, J; Groebner, R J [General Atomics (United States); Cobb, J; Fahey, M R [Oak Ridge National Laboratory (United States); Cohen, R H; Epperly, T [Lawrence Livermore National Laboratory (United States); Estep, D J [Colorado State University (United States); Krasheninnikov, S [University of California at San Diego (United States); Malony, A D [ParaTools, Inc (United States); McCune, D C [Princeton Plasma Physics Laboratory (United States); McInnes, L; Balay, S [Argonne National Laboratory (United States); Pankin, A, E-mail: cary@txcorp.co [Lehigh University (United States)

    2009-07-01

    FACETS (Framework Application for Core-Edge Transport Simulations), is now in its third year. The FACETS team has developed a framework for concurrent coupling of parallel computational physics for use on Leadership Class Facilities (LCFs). In the course of the last year, FACETS has tackled many of the difficult problems of moving to parallel, integrated modeling by developing algorithms for coupled systems, extracting legacy applications as components, modifying them to run on LCFs, and improving the performance of all components. The development of FACETS abides by rigorous engineering standards, including cross platform build and test systems, with the latter covering regression, performance, and visualization. In addition, FACETS has demonstrated the ability to incorporate full turbulence computations for the highest fidelity transport computations. Early indications are that the framework, using such computations, scales to multiple tens of thousands of processors. These accomplishments were a result of an interdisciplinary collaboration among computational physics, computer scientists and applied mathematicians on the team.

  20. A Dynamic Tap Allocation for Concurrent CMA-DD Equalizers

    Directory of Open Access Journals (Sweden)

    Trindade DiegovonBM

    2010-01-01

    Full Text Available Abstract This paper proposes a dynamic tap allocation for the concurrent CMA-DD equalizer as a low complexity solution for the blind channel deconvolution problem. The number of taps is a crucial factor which affects the performance and the complexity of most adaptive equalizers. Generally an equalizer requires a large number of taps in order to cope with long delays in the channel multipath profile. Simulations show that the proposed new blind equalizer is able to solve the blind channel deconvolution problem with a specified and reduced number of active taps. As a result, it minimizes the output excess mean square error due to inactive taps during and after the equalizer convergence and the hardware complexity as well.

  1. Holledge gauge failure testing using concurrent information processing algorithm

    International Nuclear Information System (INIS)

    Weeks, G.E.; Daniel, W.E.; Edwards, R.E.; Jannarone, R.J.; Joshi, S.N.; Palakodety, S.S.; Qian, D.

    1996-01-01

    For several decades, computerized information processing systems and human information processing models have developed with a good deal of mutual influence. Any comprehensive psychology text in this decade uses terms that originated in the computer industry, such as ''cache'' and ''memory'', to describe human information processing. Likewise, many engineers today are using ''artificial intelligence''and ''artificial neural network'' computing tools that originated as models of human thought to solve industrial problems. This paper concerns a recently developed human information processing model, called ''concurrent information processing'' (CIP), and a related set of computing tools for solving industrial problems. The problem of focus is adaptive gauge monitoring; the application is pneumatic pressure repeaters (Holledge gauges) used to measure liquid level and density in the Defense Waste Processing Facility and the Integrated DWPF Melter System

  2. Concurrent approach for evolving compact decision rule sets

    Science.gov (United States)

    Marmelstein, Robert E.; Hammack, Lonnie P.; Lamont, Gary B.

    1999-02-01

    The induction of decision rules from data is important to many disciplines, including artificial intelligence and pattern recognition. To improve the state of the art in this area, we introduced the genetic rule and classifier construction environment (GRaCCE). It was previously shown that GRaCCE consistently evolved decision rule sets from data, which were significantly more compact than those produced by other methods (such as decision tree algorithms). The primary disadvantage of GRaCCe, however, is its relatively poor run-time execution performance. In this paper, a concurrent version of the GRaCCE architecture is introduced, which improves the efficiency of the original algorithm. A prototype of the algorithm is tested on an in- house parallel processor configuration and the results are discussed.

  3. Concurrent transition of ferroelectric and magnetic ordering near room temperature.

    Science.gov (United States)

    Ko, Kyung-Tae; Jung, Min Hwa; He, Qing; Lee, Jin Hong; Woo, Chang Su; Chu, Kanghyun; Seidel, Jan; Jeon, Byung-Gu; Oh, Yoon Seok; Kim, Kee Hoon; Liang, Wen-I; Chen, Hsiang-Jung; Chu, Ying-Hao; Jeong, Yoon Hee; Ramesh, Ramamoorthy; Park, Jae-Hoon; Yang, Chan-Ho

    2011-11-29

    Strong spin-lattice coupling in condensed matter gives rise to intriguing physical phenomena such as colossal magnetoresistance and giant magnetoelectric effects. The phenomenological hallmark of such a strong spin-lattice coupling is the manifestation of a large anomaly in the crystal structure at the magnetic transition temperature. Here we report that the magnetic Néel temperature of the multiferroic compound BiFeO(3) is suppressed to around room temperature by heteroepitaxial misfit strain. Remarkably, the ferroelectric state undergoes a first-order transition to another ferroelectric state simultaneously with the magnetic transition temperature. Our findings provide a unique example of a concurrent magnetic and ferroelectric transition at the same temperature among proper ferroelectrics, taking a step toward room temperature magnetoelectric applications.

  4. Medium Access Control for Opportunistic Concurrent Transmissions under Shadowing Channels.

    Science.gov (United States)

    Son, In Keun; Mao, Shiwen; Hur, Seung Min

    2009-01-01

    We study the problem of how to alleviate the exposed terminal effect in multi-hop wireless networks in the presence of log-normal shadowing channels. Assuming node location information, we propose an extension of the IEEE 802.11 MAC protocol that sched-ules concurrent transmissions in the presence of log-normal shadowing, thus mitigating the exposed terminal problem and improving network throughput and delay performance. We observe considerable improvements in throughput and delay achieved over the IEEE 802.11 MAC under various network topologies and channel conditions in ns-2 simulations, which justify the importance of considering channel randomness in MAC protocol design for multi-hop wireless networks.

  5. Concurrent chemoradiation for oesophageal cancer: factor influencing myelotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    MacKean, J.; Denham, J.W. [Newcastle Mater Misericordiae Hospital, NSW (Australia). Radiation Oncology Department; Burmeister, B.H. [Queensland Radium Inst., Herston, QLD (Australia); Lamb, D.S. [Wellington Hospital, Wellington (New Zealand). Wellington Regional Oncology Unit

    1996-11-01

    Concurrent chemotherapy and radiation (CT/RT) for localized oesophageal cancer can cause life-threatening myelosuppression. This non-randomized study examines 95 patients from three Australasian centres treated on the TransTasman Radiation Oncology `definitive` chemoradiation study. Duration of fluorouracil infusion and patient age were independently predictive of myelotoxicity after the first cycle of CT/RT. Overall rates of grade 111 and IV neutropaenic were 23% and of thrombocytopaenia 8% following the first cycle of chemotherapy. Five neutropaenic septic episodes followed the first cycle and six the second. All five patients recovered after the first cycle but there were four treatment-related deaths occurring after the second cycle of CT/RT. Recommendations are made concerning initial dosing, dose reductions and delays to minimize adverse patient outcomes from myelosuppression. 8 refs., 4 tabs., 3 figs.

  6. Periodic waves in nonlinear metamaterials

    International Nuclear Information System (INIS)

    Liu, Wen-Jun; Xiao, Jing-Hua; Yan, Jie-Yun; Tian, Bo

    2012-01-01

    Periodic waves are presented in this Letter. With symbolic computation, equations for monochromatic waves are studied, and analytic periodic waves are obtained. Factors affecting properties of periodic waves are analyzed. Nonlinear metamaterials, with the continuous distribution of the dielectric permittivity obtained, are different from the ones with the discrete distribution. -- Highlights: ► Equations for the monochromatic waves in transverse magnetic polarization have been studied. ► Analytic periodic waves for the equations have been obtained. ► Periodic waves are theoretically presented and studied in the nonlinear metamaterials.

  7. Nonlinear Optics of Hexaphenyl Nanofibers

    DEFF Research Database (Denmark)

    Balzer, Frank; Al-Shamery, Katharina; Neuendorf, Rolf

    2003-01-01

    The nonlinear optical response of films of needle-shaped para-hexaphenyl nanoaggregates on mica surfaces is investigated. Two-photon luminescence as well as optical second harmonic generation (SHG) are observed following excitation with femtosecond pulses at 770 nm. Polarization dependent...... measurements reveal that the nonlinear optical transition dipole moment is oriented with an angle of 75° with respect to the needles long axes. The absolute value of the macroscopic second-order susceptibility, averaged over a size distribution of p-6P nanoaggregates, is estimated to be of the order of 6...

  8. Nonlinear waves and weak turbulence

    CERN Document Server

    Zakharov, V E

    1997-01-01

    This book is a collection of papers on dynamical and statistical theory of nonlinear wave propagation in dispersive conservative media. Emphasis is on waves on the surface of an ideal fluid and on Rossby waves in the atmosphere. Although the book deals mainly with weakly nonlinear waves, it is more than simply a description of standard perturbation techniques. The goal is to show that the theory of weakly interacting waves is naturally related to such areas of mathematics as Diophantine equations, differential geometry of waves, Poincaré normal forms, and the inverse scattering method.

  9. Nonlinear Control of Heartbeat Models

    Directory of Open Access Journals (Sweden)

    Witt Thanom

    2011-02-01

    Full Text Available This paper presents a novel application of nonlinear control theory to heartbeat models. Existing heartbeat models are investigated and modified by incorporating the control input as a pacemaker to provide the control channel. A nonlinear feedback linearization technique is applied to force the output of the systems to generate artificial electrocardiogram (ECG signal using discrete data as the reference inputs. The synthetic ECG may serve as a flexible signal source to assess the effectiveness of a diagnostic ECG signal-processing device.

  10. Nonlinear phenomena at cyclotron resonance

    International Nuclear Information System (INIS)

    Subbarao, D.; Uma, R.

    1986-01-01

    Finite amplitude electromagnetic waves in a magnetoplasma which typically occur in situations as in present day wave heating, current drives and other schemes in magnetically confined fusion systems, can show qualitatively different absorption and emission characteristics around resonant frequencies of the plasma because of anharmonicity. Linear wave plasma coupling as well as weak nonlinear effects such as parametric instabilities generally overlook this important effect even though the thresholds for the two phenomena as shown here are comparable. Though the effects described here are relevant to a host of nonlinear resonance effects in fusion plasmas, the authors mainly limit themselves to ECRH

  11. Field guide to nonlinear optics

    CERN Document Server

    Powers, Peter E

    2013-01-01

    Optomechanics is a field of mechanics that addresses the specific design challenges associated with optical systems. This [i]Field Guide [/i]describes how to mount optical components, as well as how to analyze a given design. It is intended for practicing optical and mechanical engineers whose work requires knowledge in both optics and mechanics. This Field Guide is designed for those looking for a condensed and concise source of key concepts, equations, and techniques for nonlinear optics. Topics covered include technologically important effects, recent developments in nonlinear optics

  12. Time series with tailored nonlinearities

    Science.gov (United States)

    Räth, C.; Laut, I.

    2015-10-01

    It is demonstrated how to generate time series with tailored nonlinearities by inducing well-defined constraints on the Fourier phases. Correlations between the phase information of adjacent phases and (static and dynamic) measures of nonlinearities are established and their origin is explained. By applying a set of simple constraints on the phases of an originally linear and uncorrelated Gaussian time series, the observed scaling behavior of the intensity distribution of empirical time series can be reproduced. The power law character of the intensity distributions being typical for, e.g., turbulence and financial data can thus be explained in terms of phase correlations.

  13. Finite elements of nonlinear continua

    CERN Document Server

    Oden, John Tinsley

    1972-01-01

    Geared toward undergraduate and graduate students, this text extends applications of the finite element method from linear problems in elastic structures to a broad class of practical, nonlinear problems in continuum mechanics. It treats both theory and applications from a general and unifying point of view.The text reviews the thermomechanical principles of continuous media and the properties of the finite element method, and then brings them together to produce discrete physical models of nonlinear continua. The mathematical properties of these models are analyzed, along with the numerical s

  14. Concurrent whole brain radiotherapy and bortezomib for brain metastasis

    International Nuclear Information System (INIS)

    Lao, Christopher D; Hamstra, Daniel; Lawrence, Theodore; Hayman, James; Redman, Bruce G; Friedman, Judah; Tsien, Christina I; Normolle, Daniel P; Chapman, Christopher; Cao, Yue; Lee, Oliver; Schipper, Matt; Van Poznak, Catherine

    2013-01-01

    Survival of patients with brain metastasis particularly from historically more radio-resistant malignancies remains dismal. A phase I study of concurrent bortezomib and whole brain radiotherapy was conducted to determine the tolerance and safety of this approach in patients with previously untreated brain metastasis. A phase I dose escalation study evaluated the safety of bortezomib (0.9, 1.1, 1.3, 1.5, and 1.7 mg/m 2 ) given on days 1, 4, 8 and 11 of whole brain radiotherapy. Patients with confirmed brain metastasis were recruited for participation. The primary endpoint was the dose-limiting toxicity, defined as any ≥ grade 3 non-hematologic toxicity or grade ≥ 4 hematologic toxicity from the start of treatment to one month post irradiation. Time-to-Event Continual Reassessment Method (TITE-CRM) was used to determine dose escalation. A companion study of brain diffusion tensor imaging MRI was conducted on a subset of patients to assess changes in the brain that might predict delayed cognitive effects. Twenty-four patients were recruited and completed the planned therapy. Patients with melanoma accounted for 83% of all participants. The bortezomib dose was escalated as planned to the highest dose of 1.7 mg/m 2 /dose. No grade 4/5 toxicities related to treatment were observed. Two patients had grade 3 dose-limiting toxicities (hyponatremia and encephalopathy). A partial or minor response was observed in 38% of patients. Bortezomib showed greater demyelination in hippocampus-associated white matter structures on MRI one month after radiotherapy compared to patients not treated with bortezomib (increase in radial diffusivity +16.8% versus 4.8%; p = 0.0023). Concurrent bortezomib and whole brain irradiation for brain metastasis is well tolerated at one month follow-up, but MRI changes that have been shown to predict delayed cognitive function can be detected within one month of treatment

  15. Definitive concurrent chemoradiotherapy in locally advanced pancreatic cancer

    International Nuclear Information System (INIS)

    Kwak, Yoo Kang; Lee, Jong Hoon; Lee, Myung Ah; Chun, Hoo Geun; Kim, Dong Goo; You, Young Kyoung; Hong, Tae Ho; Jang, Hong Seok

    2014-01-01

    Survival outcome of locally advanced pancreatic cancer has been poor and little is known about prognostic factors of the disease, especially in locally advanced cases treated with concurrent chemoradiation. This study was to analyze overall survival and prognostic factors of patients treated with concurrent chemoradiotherapy (CCRT) in locally advanced pancreatic cancer. Medical records of 34 patients diagnosed with unresectable pancreatic cancer and treated with definitive CCRT, from December 2003 to December 2012, were reviewed. Median prescribed radiation dose was 50.4 Gy (range, 41.4 to 55.8 Gy), once daily, five times per week, 1.8 to 3 Gy per fraction. With a mean follow-up of 10 months (range, 0 to 49 months), median overall survival was 9 months. The 1- and 2-year survival rates were 40% and 10%, respectively. Median and mean time to progression were 5 and 7 months, respectively. Prognostic parameters related to overall survival were post-CCRT CA19-9 (p = 0.02), the Eastern Cooperative Oncology Group (ECOG) status (p < 0.01), and radiation dose (p = 0.04) according to univariate analysis. In multivariate analysis, post-CCRT CA19-9 value below 180 U/mL and ECOG status 0 or 1 were statistically significant independent prognostic factors associated with improved overall survival (p < 0.01 and p = 0.02, respectively). Overall treatment results in locally advanced pancreatic cancer are relatively poor and few improvements have been accomplished in the past decades. Post-treatment CA19-9 below 180 U/mL and ECOG performance status 0 and 1 were significantly associated with an improved overall survival.

  16. MATHEMATICAL SIMULATION OF CONCURRENT TWO-SIDED LENS PROCESSING

    Directory of Open Access Journals (Sweden)

    A. S. Kozeruk

    2015-01-01

    Full Text Available The purpose of the paper is to modernize technology for obtaining high-accuracy lenses with fine centre. Presently their operating surfaces are fixed  to an accessory with the help of adhesive substance that leads to elastic deformation in glass and causes local errors in lens parts.A mathematical model for concurrent two-sided processing of high-accuracy optical parts with spherical surfaces has been developed in the paper. The paper presents analytical expressions that permit to calculate sliding speed at any point on the processed spherical surface depending on type and value of technological equipment settings. Calculation of parameter Q = Pv in a diametric section of the convexo-concave lens has been carried out while using these expressions together with functional dependence of pressure on contact zone еarea of tool and part bedding surfaces.Theoretical and experimental investigations have been carried out with the purpose to study changes in Q parameter according to the processed lens surface for various setting parameters of the technological equipment and their optimum values ensuring preferential stock removal in the central or boundary part zone or uniform distribution of the removal along the whole processed surface have been determined in the paper.The paper proposes a machine tool scheme for concurrent two-sided grinding and polishing of lenses while fixing their side (cylindrical surface. Machine tool kinematics makes it possible flexibly and within wide limits to change its setting parameters  that significantly facilitates the control of form-building process of parts with highly-precise spherical surfaces.Methodology for investigations presupposes the following: mathematical simulation of highly-precise spherical surface form-building process under conditions of forced closing, execution of numerical and experimental studies.  

  17. Analyzing and designing object-oriented missile simulations with concurrency

    Science.gov (United States)

    Randorf, Jeffrey Allen

    2000-11-01

    A software object model for the six degree-of-freedom missile modeling domain is presented. As a precursor, a domain analysis of the missile modeling domain was started, based on the Feature-Oriented Domain Analysis (FODA) technique described by the Software Engineering Institute (SEI). It was subsequently determined the FODA methodology is functionally equivalent to the Object Modeling Technique. The analysis used legacy software documentation and code from the ENDOSIM, KDEC, and TFrames 6-DOF modeling tools, including other technical literature. The SEI Object Connection Architecture (OCA) was the template for designing the object model. Three variants of the OCA were considered---a reference structure, a recursive structure, and a reference structure with augmentation for flight vehicle modeling. The reference OCA design option was chosen for maintaining simplicity while not compromising the expressive power of the OMT model. The missile architecture was then analyzed for potential areas of concurrent computing. It was shown how protected objects could be used for data passing between OCA object managers, allowing concurrent access without changing the OCA reference design intent or structure. The implementation language was the 1995 release of Ada. OCA software components were shown how to be expressed as Ada child packages. While acceleration of several low level and other high operations level are possible on proper hardware, there was a 33% degradation of 4th order Runge-Kutta integrator performance of two simultaneous ordinary differential equations using Ada tasking on a single processor machine. The Defense Department's High Level Architecture was introduced and explained in context with the OCA. It was shown the HLA and OCA were not mutually exclusive architectures, but complimentary. HLA was shown as an interoperability solution, with the OCA as an architectural vehicle for software reuse. Further directions for implementing a 6-DOF missile modeling

  18. Evaluation of concurrent malaria and dengue infections among febrile patients

    Directory of Open Access Journals (Sweden)

    Parul D Shah

    2017-01-01

    Full Text Available Context: Despite a wide overlap between endemic areas for two important vector-borne infections, malaria and dengue, published reports of co-infections are scarce till date. Aims: To find the incidence of dengue and malaria co-infection as well as to ascertain the severity of such dengue and malaria co-infection based on clinical and haematological parameters. Setting and Design: Observational, retrospective cross-sectional study was designed including patients who consulted the tertiary care hospital of Ahmedabad seeking treatment for fever compatible with malaria and/or dengue. Subjects and Methods: A total of 8364 serum samples from clinically suspected cases of fever compatible with malaria and/or dengue were collected. All samples were tested for dengue NS-1 antigen before 5 days of onset of illness and for dengue IgM after 5 days of onset of illness. In all samples, malaria diagnosis was based on the identification of Plasmodium parasites on a thin and thick blood films microscopy. Results: Only 10.27% (859 patients with fever were tested positive for dengue and 5.1% (434 were tested positive for malaria. 3.14% (27 dengue cases show concurrent infection with malarial parasites. Hepatomegaly and jaundice 37.03% (10, haemorrhagic manifestations 18.51% (5 and kidney failure 3.7% (1, haemoglobin <12 g/dl 100% (27 and thrombocytopenia (platelet count <150,000/cmm 96.29% (26 were common in malaria and dengue co-infections and were much more common in Plasmodium falciparum infections. Conclusion: All febrile patients must be tested for malaria and dengue, both otherwise one of them will be missed in case of concurrent infections which could lead to severe diseases with complications.

  19. Preoperative concurrent chemo-radiation in rectal cancer

    International Nuclear Information System (INIS)

    Berger, C.; Kirscher, S.; Felix-Faure, C.; Chauvet, B.; Vincent, P.; Brewer, Y.; Reboul, F.

    1998-01-01

    To evaluate retrospectively treatment-related morbidity of concurrent radiotherapy and chemotherapy for rectal cancer. Between 1992 and 1995, 38 patients (median age: 60) were treated for locally advanced resectable rectal cancer. Median dose of radiotherapy was 45 Gy/25 fractions/5 weeks. Chemotherapy consisted of two courses of 5-fluorouracil and leucovorin administered during the first and the fifth weeks of radiotherapy. Median dose of 5-fluorouracil was 350 mg/m 2 /day, and median dose of leucovorin was 350 mg/m 2 /day, day 1 to day 5. Surgery was performed 5 weeks after completion of radiotherapy. Before surgery, one patient died of febrile neutropenia and sepsis after two cycles of chemotherapy and 45 Gy. Main pre-operative grade 3-4 toxicities were respectively: neutropenia: 3% ; nausea/vomiting: 3%; diarrhea: 3%; proctitis: 5%; radiation dermatitis: 8%. Twenty-six patients underwent a low anterior resection and 11 an abdomino-perineal resection. A temporary colostomy was performed in 12 patients. Pathologic complete response rate was 27 %. There was one post-operative death due to thrombo-embolic disease. Major post-operative grade 3-4 complications were: pelvic infection: 14 %; abdominal infection : 5%; perineal sepsis: 8%; anastomotic dehiscence: 8%; cardiac failure: 5%. Delayed perineal wound healing was observed in six patients. No significant prognostic factor of post-operative complications has been observed. Median duration of hospitalization was 22 days. With a median follow-up of 24 months, 2-year overall and disease-free survival rates were 82 and 64%. Tolerance of preoperative concurrent chemoradiotherapy was acceptable. Ongoing controlled studies will assess the impact of this combined treatment on survival. (authors)

  20. Concurrency and climate change signal in Scottish flooding

    Science.gov (United States)

    Harding, A. E.; Butler, A.; Goody, N.; Bertram, D.; Baggaley, N.; Tett, S. F.

    2013-12-01

    The Scottish Environment Protection Agency maintains a database of river gauging stations and intensity rain-gauges with a 3-hourly resolution that covers the majority of Scotland. Both SEPA and a number of other Scottish agencies are invested in climate change attribution in this data set. SEPA's main interest lies in trend detection and changes in river level (';stage') data throughout Scotland. Emergency response teams are more concerned with the concurrency of multiple flood events that might stretch their ability to respond effectively. Unfortunately, much of the rainfall signal within SEPA's river-gauge data is altered by land use changes, modified by artificial interventions such as reservoirs, compromised by tidal flow, or obscured by measurement issues. Data reduction techniques, indices of extreme rainfall, and hydrology-driven discrimination have been employed to produce a reduced set of flood-relevant information for 24-hour ';flashy' events. Links between this set and North Atlantic circulation have been explored, as have patterns of mutual occurrence across Scotland and location- and seasonally- dependent trends through time. Both frontal systems and summer convective storms have been characterised in terms of subsequent flood-inducing flow regime, their changing behaviour over the last fifty years, and their spatial extent. This is the first stage of an ongoing project that will intelligently expand to take less robust river and rain-gauge stations into account through statistical analysis and hydrological modelling. It is also the first study of its type to analyse a nation-scale dataset of both rainfall and river flow from multiple catchments for flood event concurrency. As rainfall events are expected to intensify across much of Europe, this kind of research is likely to have an increasing degree of relevance for policy-makers. This project demonstrates that productive, policy-relevant and mutually-rewarding partnerships are already underway.