3,622 research outputs found

    Global stability of Vegas-like TCP flow

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    A TCP Vegas flow adapts its sending rate to maintain a constant backlog in its path. The stability of nonlinear adaptation has been analyzed based on linearization and only accounted for a small signal. We extend the error model of TCP-like flow to a state-dependent coefficient form with nonlinear state feedback. The nonlinear feedback is here approximated by a saturation function. Using a quadratic Lyapunov function approach, we find a domain of attraction to show that the unique equilibrium point of the system is asymptotically stable in the domain

    Phantom for Evaluating Accuracy of Image Registration Software

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    Provided is a phantom for evaluating the accuracy of image registration software based on a result of matching tomograms of a predetermined position of the phantom, taken using two or more imaging apparatuses. Accordingly, it is possible to more efficiently evaluate the accuracy of the image registration software by comparing the tomograms with one another using a three-dimensional analysis. In addition, it is possible to facilitate the comparison of the tomograms with one another by installing a plurality of indicating bars in the phantom so that their cross sections can appear on each of the tomograms

    Polarization Switching Dynamics Governed by Thermodynamic Nucleation Process in Ultrathin Ferroelectric Films

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    A long standing problem of domain switching process - how domains nucleate - is examined in ultrathin ferroelectric films. We demonstrate that the large depolarization fields in ultrathin films could significantly lower the nucleation energy barrier (U*) to a level comparable to thermal energy (kBT), resulting in power-law like polarization decay behaviors. The "Landauer's paradox": U* is thermally insurmountable is not a critical issue in the polarization switching of ultrathin ferroelectric films. We empirically find a universal relation between the polarization decay behavior and U*/kBT.Comment: 5 pages, 4 figure

    Transient co-singing of offspring and mothers in non-duetting Javan gibbons (Hylobates moloch)

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    While the vocalizations of non-human primates were thought to be innate, recent studies have revealed highly flexible vocalizations in immatures. This behavior suggests that social influences have an important role in developing vocalizations. Yet not much is known about how non-human primate vocalization develop and how the vocalizations of immature animals differ between sexes. Here, we analyzed 95 cases of co-singing between mothers and offspring out of 240 female songs from three groups of wild Javan gibbon (Hylobates moloch) in Gunung Halimun-Salak National Park, Indonesia, between 2009 and 2021. Hylobates moloch is one of only two gibbon species with pairs that do not duet. Instead, they produce sex-specific solo songs. We found that both offspring female and male H. moloch follow their mothers’ female-specific songs, similar to other duetting gibbon species. Immatures started co-singing with their mothers from 7 months old, but with an average starting age of about 24 months. As female offspring grew older, they co-sung with mothers more often while male offspring did not. After 7 years of age, both sexes stopped co-singing with their mothers and started singing alone, following their own sex-specific vocalizations. We did not find any relation between male offspring co-singing and territorial functions (e.g., co-singing more during intergroup encounters or closer to home range borders). Our results suggest that mothers’ songs may trigger male offspring and females to practice singing, but not specifically for males to defend territories. We highlight that despite the absence of duets, H. moloch develop their vocalizations from early infancy and throughout their maturation while co-singing with mothers. However, the level of co-singing varies depending on the sexes. Our study is the first to elucidate the sex-specific trajectories of vocal development in H. moloch across years, indicating that offspring in non-duetting gibbons co-sing with mothers like in duetting species

    Strange meson-nucleon states in the quark potential model

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    The quark potential model and resonating group method are used to investigate the KˉN\bar{K}N bound states and/or resonances. The model potential consists of the t-channel and s-channel one-gluon exchange potentials and the confining potential with incorporating the QCD renormalization correction and the spin-orbital suppression effect in it. It was shown in our previous work that by considering the color octet contribution, use of this model to investigate the KNKN low energy elastic scattering leads to the results which are in pretty good agreement with the experimental data. In this paper, the same model and method are employed to calculate the masses of the KˉN\bar{K}N bound systems. For this purpose, the resonating group equation is transformed into a standard Schr\"odinger equation in which a nonlocal effective KˉN\bar{K}N interaction potential is included. Solving the Schr\"odinger equation by the variational method, we are able to reproduce the masses of some currently concerned KˉN\bar{K}N states and get a view that these states possibly exist as KˉN\bar{K}N molecular states. For the KNKN system, the same calculation gives no support to the existence of the resonance Θ+(1540)\Theta ^{+}(1540) which was announced recently.Comment: 15 pages, 4 figure
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