884 research outputs found
Intelligent Omni Surfaces assisted Integrated Multi Target Sensing and Multi User MIMO Communications
Drawing inspiration from the advantages of intelligent reflecting surfaces
(IRS) in wireless networks,this paper presents a novel design for intelligent
omni surface (IOS) enabled integrated sensing and communications (ISAC). By
harnessing the power of multi antennas and a multitude of elements, the
dual-function base station (BS) and IOS collaborate to realize joint active and
passive beamforming, enabling seamless 360-degree ISAC coverage. The objective
is to maximize the minimum signal-tointerference-plus-noise ratio (SINR) of
multi-target sensing, while ensuring the multi-user multi-stream
communications. To achieve this, a comprehensive optimization approach is
employed, encompassing the design of radar receive vector, transmit beamforming
matrix, and IOS transmissive and reflective coefficients. Due to the non-convex
nature of the formulated problem, an auxiliary variable is introduced to
transform it into a more tractable form. Consequently, the problem is
decomposed into three subproblems based on the block coordinate descent
algorithm. Semidefinite relaxation and successive convex approximation methods
are leveraged to convert the sub-problem into a convex problem, while the
iterative rank minimization algorithm and penalty function method ensure the
equivalence. Furthermore,the scenario is extended to mode switching and time
switching protocols. Simulation results validate the convergence and superior
performance of the proposed algorithm compared to other benchmark algorithms.Comment: 30 pages, 7 figure
BeautifulPrompt: Towards Automatic Prompt Engineering for Text-to-Image Synthesis
Recently, diffusion-based deep generative models (e.g., Stable Diffusion)
have shown impressive results in text-to-image synthesis. However, current
text-to-image models often require multiple passes of prompt engineering by
humans in order to produce satisfactory results for real-world applications. We
propose BeautifulPrompt, a deep generative model to produce high-quality
prompts from very simple raw descriptions, which enables diffusion-based models
to generate more beautiful images. In our work, we first fine-tuned the
BeautifulPrompt model over low-quality and high-quality collecting prompt
pairs. Then, to ensure that our generated prompts can generate more beautiful
images, we further propose a Reinforcement Learning with Visual AI Feedback
technique to fine-tune our model to maximize the reward values of the generated
prompts, where the reward values are calculated based on the PickScore and the
Aesthetic Scores. Our results demonstrate that learning from visual AI feedback
promises the potential to improve the quality of generated prompts and images
significantly. We further showcase the integration of BeautifulPrompt to a
cloud-native AI platform to provide better text-to-image generation service in
the cloud.Comment: emnlp 202
On the Performance of RIS-Aided Spatial Scattering Modulation for mmWave Transmission
In this paper, we investigate a state-of-the-art reconfigurable intelligent
surface (RIS)-assisted spatial scattering modulation (SSM) scheme for
millimeter-wave (mmWave) systems, where a more practical scenario that the RIS
is near the transmitter while the receiver is far from RIS is considered. To
this end, the line-of-sight (LoS) and non-LoS links are utilized in the
transmitter-RIS and RIS-receiver channels, respectively. By employing the
maximum likelihood detector at the receiver, the conditional pairwise error
probability (CPEP) expression for the RIS-SSM scheme is derived under the two
scenarios that the received beam demodulation is correct or not. Furthermore,
the union upper bound of average bit error probability (ABEP) is obtained based
on the CPEP expression. Finally, the derivation results are exhaustively
validated by the Monte Carlo simulations.Comment: arXiv admin note: substantial text overlap with arXiv:2307.1466
CalibRCNN:Calibrating Camera and LiDAR by recurrent convolutional neural network and geometric constraints
Quantum structural fluxion in superconducting lanthanum polyhydride
The discovery of 250-kelvin superconducting lanthanum polyhydride under high pressure marked a significant advance toward the realization of a room‐temperature superconductor. X-ray diffraction (XRD) studies reveal a nonstoichiometric LaH9.6 or LaH10±δ polyhydride responsible for the superconductivity, which in the literature is commonly treated as LaH10 without accounting for stoichiometric defects. Here, we discover significant nuclear quantum effects (NQE) in this polyhydride, and demonstrate that a minor amount of stoichiometric defects will cause quantum proton diffusion in the otherwise rigid lanthanum lattice in the ground state. The diffusion coefficient reaches ~10−7 cm2/s in LaH9.63 at 150 gigapascals and 240 kelvin, approaching the upper bound value of interstitial hydrides at comparable temperatures. A puzzling phenomenon observed in previous experiments, the positive pressure dependence of the superconducting critical temperature Tc below 150 gigapascals, is explained by a modulation of the electronic structure due to a premature distortion of the hydrogen lattice in this quantum fluxional structure upon decompression, and resulting changes of the electron-phonon coupling. This finding suggests the coexistence of the quantum proton fluxion and hydrogen-induced superconductivity in this lanthanum polyhydride, and leads to an understanding of the structural nature and superconductivity of nonstoichiomectric hydrogen-rich materials.The project is supported by the National Natural Science Foundation of China (Grant No. 11974135, 11874176, 12174170, and 12074138), the Natural Sciences and Engineering Research Council of Canada, the EPSRC through grants EP/P022596/1, and EP/S021981/1, and the startup funds of the office of the Dean of SASN of Rutgers University-Newark. P. T. S. thanks the Department of Materials Science and Metallurgy at the University of Cambridge for generous funding. The work of P. T. S. is further supported through a Trinity Hall research studentship. I. E. acknowledges financial support by the European Research Council (ERC) under the EuropeanUnion’sHorizon 2020 research and innovation program (grant agreement no. 802533)
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