3,983 research outputs found

    Traffic-Aware Transmission Mode Selection in D2D-enabled Cellular Networks with Token System

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    We consider a D2D-enabled cellular network where user equipments (UEs) owned by rational users are incentivized to form D2D pairs using tokens. They exchange tokens electronically to "buy" and "sell" D2D services. Meanwhile the devices have the ability to choose the transmission mode, i.e. receiving data via cellular links or D2D links. Thus taking the different benefits brought by diverse traffic types as a prior, the UEs can utilize their tokens more efficiently via transmission mode selection. In this paper, the optimal transmission mode selection strategy as well as token collection policy are investigated to maximize the long-term utility in the dynamic network environment. The optimal policy is proved to be a threshold strategy, and the thresholds have a monotonicity property. Numerical simulations verify our observations and the gain from transmission mode selection is observed.Comment: 7 pages, 6 figures. A shorter version is submitted to EUSIPC

    3-Chloro­pyridin-2-amine

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    In the title compound, C5H5ClN2, a by-product in the synthesis of ethyl 2-(3-chloro­pyridin-2-yl)-5-oxopyrazolidine-3-carboxyl­ate, the amine groups form inter­molecular hydrogen-bonding associations with pyridine N-atom acceptors, giving centrosymmetric cyclic dimers. Short inter­molecular Cl⋯Cl inter­actions [3.278 (3) Å] also occur

    GRB 211211A-like Events and How Gravitational Waves May Tell Their Origin

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    GRB 211211A is a rare burst with a genuinely long duration, yet its prominent kilonova association provides compelling evidence that this peculiar burst was the result of a compact binary merger. However, the exact nature of the merging objects, whether they were neutron star pairs, neutron star-black hole systems, or neutron star-white dwarf systems, remains unsettled. This Letter delves into the rarity of this event and the possibility of using current and next-generation gravitational wave detectors to distinguish between the various types of binary systems. Our research reveals an event rate density of 5.674.69+13.04×103 Gpc3yr1\gtrsim 5.67^{+13.04}_{-4.69} \times 10^{-3}\ \rm Gpc^{-3} yr^{-1} for GRB 211211A-like GRBs, which is significantly smaller than that of typical long and short GRB populations. We further calculated that if the origin of GRB 211211A is a result of a neutron star-black hole merger, it would be detectable with a significant signal-to-noise ratio, given the LIGO-Virgo-KAGRA designed sensitivity. On the other hand, a neutron star-white dwarf binary would also produce a considerable signal-to-noise ratio during the inspiral phase at decihertz and is detectable by next-generation space-borne detectors DECIGO and BBO. However, to detect this type of system with millihertz space-borne detectors like LISA, Taiji, and TianQin, the event must be very close, approximately 3 Mpc in distance or smaller.Comment: 8 pages, 3 figures, 1 tabl

    Numerical calculation of transmission noise for the magnesium alloy cylinder head cover

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    Transmission noise of the magnesium alloy cylinder head cover was researched in this paper. Firstly, the numerical calculation mode of a cylinder head cover was compared with the experimental one. Results showed that the numerical calculation model had a relatively high accuracy, and it could be used in subsequent analysis. Secondly, sound pressure inside the cylinder head cover was extracted through the four-load method and taken as the sound source. Then, it was applied in a simulation model in order to simulate transmission noise of the actual situations. Afterwards, transmission noise of the magnesium alloy cylinder head cover was compared with the aluminum alloy one. It was shown that relatively low transmission noise was generated from the magnesium alloy cylinder head cover. Meanwhile, its mass was only 0.65 times of that of the aluminum alloy one. Therefore, the requirement for low noise and light weight was achieved by the magnesium alloy cylinder head cover. Then, dynamic stresses of cylinder head covers for two materials were compared. Results showed that dynamic stress of the magnesium alloy cylinder head cover was slightly smaller than that of the aluminum alloy one. The magnesium alloy cylinder head cover satisfied the requirement for strength and had a relatively prominent comprehensive performances. Finally, sound absorption coefficient of a porous material was calculated by using the numerical simulation technology. It was also laid inside the magnesium alloy cylinder head cover to constitute a composite cylinder head cover. Transmission noise of such composite cylinder head cover was much smaller than that of the original structure. This researches provided a method for low noise and light weight design of the cylinder head cover
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