842 research outputs found

    Optimal Uniform Pricing Strategy of a Service Firm When Facing Two Classes of Customers

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106838/1/poms12171.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/106838/2/poms12171-sup-0001-Onlinesupplement.pd

    Multipolar condensates and multipolar Josephson effects

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    When single-particle dynamics are suppressed in certain strongly correlated systems, dipoles arise as elementary carriers of quantum kinetics. These dipoles can further condense, providing physicists with a rich realm to study fracton phases of matter. Whereas recent theoretical discoveries have shown that an unconventional lattice model may host a dipole condensate as the ground state, fundamental questions arise as to whether dipole condensation is a generic phenomenon rather than a specific one unique to a particular model and what new quantum macroscopic phenomena a dipole condensate may bring us with. Here, we show that dipole condensates prevail in bosonic systems. Because of a self-proximity effect, where single-particle kinetics inevitably induces a finite order parameter of dipoles, dipole condensation readily occurs in conventional normal phases of bosons. Our findings allow experimentalists to manipulate the phase of a dipole condensate and deliver dipolar Josephson effects, where supercurrents of dipoles arise in the absence of particle flows. The self-proximity effects can also be utilized to produce a generic multipolar condensate. The kinetics of the nn-th order multipoles unavoidably creates a condensate of the (n+1)(n+1)-th order multipoles, forming a hierarchy of multipolar condensates that will offer physicists a whole new class of macroscopic quantum phenomena

    DTBS: Dual-Teacher Bi-directional Self-training for Domain Adaptation in Nighttime Semantic Segmentation

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    Due to the poor illumination and the difficulty in annotating, nighttime conditions pose a significant challenge for autonomous vehicle perception systems. Unsupervised domain adaptation (UDA) has been widely applied to semantic segmentation on such images to adapt models from normal conditions to target nighttime-condition domains. Self-training (ST) is a paradigm in UDA, where a momentum teacher is utilized for pseudo-label prediction, but a confirmation bias issue exists. Because the one-directional knowledge transfer from a single teacher is insufficient to adapt to a large domain shift. To mitigate this issue, we propose to alleviate domain gap by incrementally considering style influence and illumination change. Therefore, we introduce a one-stage Dual-Teacher Bi-directional Self-training (DTBS) framework for smooth knowledge transfer and feedback. Based on two teacher models, we present a novel pipeline to respectively decouple style and illumination shift. In addition, we propose a new Re-weight exponential moving average (EMA) to merge the knowledge of style and illumination factors, and provide feedback to the student model. In this way, our method can be embedded in other UDA methods to enhance their performance. For example, the Cityscapes to ACDC night task yielded 53.8 mIoU (\%), which corresponds to an improvement of +5\% over the previous state-of-the-art. The code is available at \url{https://github.com/hf618/DTBS}

    Adaptive Control of Space Robot Manipulators with Task Space Base on Neural Network

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    As are considered, the body posture is controlled and position cannot control, space manipulator system model is difficult to be set up because of disturbance and model uncertainty. An adaptive control strategy based on neural network is put forward. Neural network on-line modeling technology is used to approximate the system uncertain model, and the strategy avoids solving the inverse Jacobi matrix, neural network approximation error and external bounded disturbance are eliminated by variable structure control controller. Inverse dynamic model of the control strategy does not need to be estimated, also do not need to take the training process, globally asymptotically stable of the closed-loop system is proved based on the lyapunov theory. The simulation results show that the designed controller can achieve high control precision has the important value of engineering application

    Delivering universal health coverage for an aging population : an analysis of the Chinese rural health insurance program

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    There is now high level international commitment to the goal of universal health coverage. But how can countries make this a reality in the face of a limited budget and an aging population? Since 2008, China has been rolling out an ambitious reform program, which aims to achieve affordable health insurance coverage for all Chinese citizens. Under this reform program, Chinese living in rural areas are eligible to enroll in a subsidized scheme called the New Cooperative Medical System (NCMS). Using a three stage game model involving a government, a private fund manager and population, we explore the impact of population aging on NCMS. Our model highlights the role of government regulation and subsidy in ensuring operation efficiency of the system. We show that at optimality the government sets the operating framework for the fund manager to constrain the potential for monopoly profits. The Government subsidizes the scheme to prevent an adverse selection death spiral. However, the effectiveness of the subsidy in achieving this goal is moderated by the age structure of the population. Our model gives insights into the strengths of the NCMS framework and also can be used to support decisions about resource allocation and understand how scheme dynamics may unfold as the Chinese population ages further

    Non-gapless excitation and zero-bias fast oscillations in the LDOS of surface superconducting states

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    Recently a novel surface pair-density-wave (PDW) superconducting state has been discovered in Refs. [Phys. Rev. Lett. \textbf{122}, 165302 (2019)] and Phys. Rev. B \textbf{101}, 054506 (2020)], which may go through a distinct multiple phase transition (MPT) when the superconductivity fades away from bulk to the boundary (e.g. edges and corners). Based on the Bogoliubov-de Gennes equations for the attractive tight-binding Hubbard modal in a one-dimensional chain, we demonstrate that the surface PDW state has a non-gapless quasiparticle spectrum, which is contrary to the conventional surface superconducting state. Moreover, we find that the MPT is associated with a zero-bias fast oscillating pattern in the LDOS near the surface. Our findings provide a potential experimental clue to identify the surface PDW state.Comment: 4 figure
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