802 research outputs found

    Observation of sub-Doppler absorption in the /Lambda-type three-level Doppler-broadened cesium system

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    Thanks to the atomic coherence in coupling laser driven atomic system, sub-Doppler absorption has been observed in Doppler-broadened cesium vapor cell via the /Lambda-type three-level scheme. The linewidth of the sub-Doppler absorption peak become narrower while the frequency detuning of coupling laser increases. The results are in agreement with the theoretical prediction by G. Vemuri et al.[PRA,Vol.53(1996) p.2842].Comment: 12 pages, 5 figures, to appear on Applied Physics

    Perturbations of Dirac operators

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    We study general conditions under which the computations of the index of a perturbed Dirac operator Ds=D+sZD_{s}=D+sZ localize to the singular set of the bundle endomorphism ZZ in the semi-classical limit s→∞s\to \infty . We show how to use Witten's method to compute the index of DD by doing a combinatorial computation involving local data at the nondegenerate singular points of the operator ZZ. In particular, we provide examples of novel deformations of the de Rham operator to establish new results relating the Euler characteristic of a spinc^{c} manifold to maps between its even and odd spinor bundles. The paper contains a list of the current literature on the subject.Comment: 34 pages, improved results, new applications, literature list update

    Brief Report of an Artificial Rearing Method for Paragus quadri-fasciatus Meigen

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    The four-striped small syrphid fly, Paragus quadri-fasciatus Meigen, is one important kind of natural enemy of aphids. Since 1983 we have studied the utilization of this natural enemy. We selected perennial grasses (of two to three years life span), which host aphids. In the first year we planted the above-mentioned grasses and in the second year we raised the syrphid fly. Details of the method are described as follows.Originating text in Chinese.Citation: Gao, Junfeng, Zhang, Li, Zhang, Shubin, Qin, Bo. (1992). Brief Report of an Artificial Rearing Method for Paragus quadri-fasciatus Meigen. Natural Enemies of Insects, 14(4), 188-190

    Sign-changing solutions for a Schrödinger-Kirchhoff-Poisson system with 4-sublinear growth nonlinearity

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    In this paper we consider the following Schrödinger–Kirchhoff–Poisson-type system where Ω is a bounded smooth domain of R3 , a > 0, b ≥ 0 are constants and λ is a positive parameter. Under suitable conditions on Q(x) and combining the method of invariant sets of descending flow, we establish the existence and multiplicity of signchanging solutions to this problem for the case that 2 < p < 4 as λ sufficiently small. Furthermore, for λ = 1 and the above assumptions on Q(x), we obtain the same conclusions with 2 < p < 12 5

    DynLight: Realize dynamic phase duration with multi-level traffic signal control

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    Adopting reinforcement learning (RL) for traffic signal control (TSC) is increasingly popular, and RL has become a promising solution for traffic signal control. However, several challenges still need to be overcome. Firstly, most RL methods use fixed action duration and select the green phase for the next state, which makes the phase duration less dynamic and flexible. Secondly, the phase sequence of RL methods can be arbitrary, affecting the real-world deployment which may require a cyclical phase structure. Lastly, the average travel time and throughput are not fair metrics to evaluate TSC performance. To address these challenges, we propose a multi-level traffic signal control framework, DynLight, which uses an optimization method Max-QueueLength (M-QL) to determine the phase and uses a deep Q-network to determine the duration of the corresponding phase. Based on DynLight, we further propose DynLight-C which adopts a well-trained deep Q-network of DynLight and replace M-QL with a cyclical control policy that actuates a set of phases in fixed cyclical order to realize cyclical phase structure. Comprehensive experiments on multiple real-world datasets demonstrate that DynLight achieves a new state-of-the-art. Furthermore, the deep Q-network of DynLight can learn well on determining the phase duration and DynLight-C demonstrates high performance for deployment.Comment: 9 pages, 9 figure

    A Review of Sequential Decision Making via Simulation

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    Optimization via simulation has been well established to find optimal solutions and designs in complex systems. However, it still faces modeling and computational challenges when extended to the multi-stage setting. This survey reviews the models and methodologies of single-stage optimization via simulation and multi-stage stochastic programming. These are necessary theoretical components to push forward the development of sequential decision making via simulation. We identify the key challenge of sequential decision making via simulation as the appropriate modeling of the stage-wise value function, for which we survey the state-of-the-art meta-models and their potential solution algorithms
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