754 research outputs found

    The entropy reduction engine: Integrating planning, scheduling, and control

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    The Entropy Reduction Engine, an architecture for the integration of planning, scheduling, and control, is described. The architecture is motivated, presented, and analyzed in terms of its different components; namely, problem reduction, temporal projection, and situated control rule execution. Experience with this architecture has motivated the recent integration of learning. The learning methods are described along with their impact on architecture performance

    Universal relaxational dynamics of gapped one dimensional models in the quantum sine-Gordon universality class

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    A semiclassical approach to the low-temperature real time dynamics of generic one-dimensional, gapped models in the sine-Gordon model universality class is developed. Asymptotically exact universal results for correlation functions are obtained in the temperature regime T << Delta, where Delta is the energy gap.Comment: 4 pages, 1 figur

    The blind leading the blind: Mutual refinement of approximate theories

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    The mutual refinement theory, a method for refining world models in a reactive system, is described. The method detects failures, explains their causes, and repairs the approximate models which cause the failures. The approach focuses on using one approximate model to refine another

    Symmetry breaking perturbations and strange attractors

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    The asymmetrically forced, damped Duffing oscillator is introduced as a prototype model for analyzing the homoclinic tangle of symmetric dissipative systems with \textit{symmetry breaking} disturbances. Even a slight fixed asymmetry in the perturbation may cause a substantial change in the asymptotic behavior of the system, e.g. transitions from two sided to one sided strange attractors as the other parameters are varied. Moreover, slight asymmetries may cause substantial asymmetries in the relative size of the basins of attraction of the unforced nearly symmetric attracting regions. These changes seems to be associated with homoclinic bifurcations. Numerical evidence indicates that \textit{strange attractors} appear near curves corresponding to specific secondary homoclinic bifurcations. These curves are found using analytical perturbational tools

    Cyclic mutually unbiased bases, Fibonacci polynomials and Wiedemann's conjecture

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    We relate the construction of a complete set of cyclic mutually unbiased bases, i. e., mutually unbiased bases generated by a single unitary operator, in power-of-two dimensions to the problem of finding a symmetric matrix over F_2 with an irreducible characteristic polynomial that has a given Fibonacci index. For dimensions of the form 2^(2^k) we present a solution that shows an analogy to an open conjecture of Wiedemann in finite field theory. Finally, we discuss the equivalence of mutually unbiased bases.Comment: 11 pages, added chapter on equivalenc

    Non-ergodicity of the motion in three dimensional steep repelling dispersing potentials

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    It is demonstrated numerically that smooth three degrees of freedom Hamiltonian systems which are arbitrarily close to three dimensional strictly dispersing billiards (Sinai billiards) have islands of effective stability, and hence are non-ergodic. The mechanism for creating the islands are corners of the billiard domain.Comment: 6 pages, 8 figures, submitted to Chao

    Parabolic resonances and instabilities in near-integrable two degrees of freedom Hamiltonian flows

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    When an integrable two-degrees-of-freedom Hamiltonian system possessing a circle of parabolic fixed points is perturbed, a parabolic resonance occurs. It is proved that its occurrence is generic for one parameter families (co-dimension one phenomenon) of near-integrable, t.d.o. systems. Numerical experiments indicate that the motion near a parabolic resonance exhibits new type of chaotic behavior which includes instabilities in some directions and long trapping times in others. Moreover, in a degenerate case, near a {\it flat parabolic resonance}, large scale instabilities appear. A model arising from an atmospherical study is shown to exhibit flat parabolic resonance. This supplies a simple mechanism for the transport of particles with {\it small} (i.e. atmospherically relevant) initial velocities from the vicinity of the equator to high latitudes. A modification of the model which allows the development of atmospherical jets unfolds the degeneracy, yet traces of the flat instabilities are clearly observed

    Prescription auditing: an important tool for sensitization of resident doctors for rationale prescription and utilization of drug

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    Background: The main objective of the Maharashtra Health Systems Development Project (MHSDP) is to enhance the quality of care by improving health care; in the hospitals, in the state. Improvement in the prescribing practice of resident doctors working in the hospitals is one of the initiatives taken up, to improve the rationalizing service delivery. A prescription audit may become an important tool for sensitizing resident doctors for rational prescription and utilization of drug.Methods: An observational study was carried out during the period of March 2017 to May 2017 in tertiary care teaching hospital, Kolhapur. Total 247 first prescriptions written by resident for in-door-patient department were collected, scrutinized and analysed. Prescriptions were evaluated for completeness of prescription format while legibility was graded. Prescriptions were also analysed as per World Health Organization prescribing indicators.Results: In study 247 prescriptions with 1091 drugs with average 4.42% drugs per prescription, 49.8 % prescriptions wrote the drugs by generic name. We found that 44.1 % prescriptions written with drugs included in essential medicines list while antibiotics prescribed were 27.1%. In prescription format 34% had incorrect dosage, 67% of prescriptions omitted the duration of treatment. Direction for drug use was not mentioned in 25% of prescriptions.  Weight was not mentioned on any prescriptions even for paediatric group.Conclusions: Through prescription auditing, sensitizing resident doctors for rational prescription and utilization of drug can be done to achieve the goal of the MHSDP of enhancing the quality of care by improving health care; in the hospitals, in the state

    Stickiness in Hamiltonian systems: from sharply divided to hierarchical phase space

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    We investigate the dynamics of chaotic trajectories in simple yet physically important Hamiltonian systems with non-hierarchical borders between regular and chaotic regions with positive measures. We show that the stickiness to the border of the regular regions in systems with such a sharply divided phase space occurs through one-parameter families of marginally unstable periodic orbits and is characterized by an exponent \gamma= 2 for the asymptotic power-law decay of the distribution of recurrence times. Generic perturbations lead to systems with hierarchical phase space, where the stickiness is apparently enhanced due to the presence of infinitely many regular islands and Cantori. In this case, we show that the distribution of recurrence times can be composed of a sum of exponentials or a sum of power-laws, depending on the relative contribution of the primary and secondary structures of the hierarchy. Numerical verification of our main results are provided for area-preserving maps, mushroom billiards, and the newly defined magnetic mushroom billiards.Comment: To appear in Phys. Rev. E. A PDF version with higher resolution figures is available at http://www.pks.mpg.de/~edugal
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