3,983 research outputs found
Traffic-Aware Transmission Mode Selection in D2D-enabled Cellular Networks with Token System
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
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Quantification of atherosclerotic plaque volume in coronary arteries by computed tomographic angiography in subjects with and without diabetes.
BackgroundDiabetes mellitus (DM) is considered a cardiovascular risk factor. The aim of this study was to analyze the prevalence and volume of coronary artery plaque in patients with diabetes mellitus (DM) vs. those without DM.MethodsThis study recruited consecutive patients who underwent coronary computed tomography (CT) angiography (CCTA) between October 2016 and November 2017. Personal information including conventional cardiovascular risk factors was collected. Plaque phenotypes were automatically calculated for volume of different component. The volume of different plaque was compared between DM patients and those without DM.ResultsAmong 6381 patients, 931 (14.59%) were diagnosed with DM. The prevalence of plaque in DM subjects was higher compared with nondiabetic group significantly (48.34% vs. 33.01%, χ = 81.84, P < 0.001). DM was a significant risk factor for the prevalence of plaque in a multivariate model (odds ratio [OR] = 1.465, 95% CI: 1.258-1.706, P < 0.001). The volume of total plaque and any plaque subtypes in the DM subjects was greater than those in nondiabetic patients significantly (P < 0.001).ConclusionThe coronary artery atherosclerotic plaques were significantly higher in diabetic patients than those in non-diabetic patients
3-Chloropyridin-2-amine
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
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 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
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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