14,152 research outputs found

    PABO: Mitigating Congestion via Packet Bounce in Data Center Networks

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    In today's data center, a diverse mix of throughput-sensitive long flows and delay-sensitive short flows are commonly presented in shallow-buffered switches. Long flows could potentially block the transmission of delay-sensitive short flows, leading to degraded performance. Congestion can also be caused by the synchronization of multiple TCP connections for short flows, as typically seen in the partition/aggregate traffic pattern. While multiple end-to-end transport-layer solutions have been proposed, none of them have tackled the real challenge: reliable transmission in the network. In this paper, we fill this gap by presenting PABO -- a novel link-layer design that can mitigate congestion by temporarily bouncing packets to upstream switches. PABO's design fulfills the following goals: i) providing per-flow based flow control on the link layer, ii) handling transient congestion without the intervention of end devices, and iii) gradually back propagating the congestion signal to the source when the network is not capable to handle the congestion.Experiment results show that PABO can provide prominent advantage of mitigating transient congestions and can achieve significant gain on end-to-end delay

    Vehicle Anti-lock Braking System Performance using dSPACE

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    As a typical active safety component for automotives, the main goal of the Anti-lock Braking System (ABS) is to prevent wheel lockup and to maintain steerability and stability. This paper focuses on using a model-based approach for developing a mathematical model of ABS. Three different Simulink models are set up for simulation. By using dSAPCE MicroAutoBoxⅡ, the simulation results are listed in this paper

    Double-charm and hidden-charm hexaquark states under the complex scaling method

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    We investigate the double-charm and hidden-charm hexaquarks as molecules in the framework of the one-boson-exchange potential model. The multichannel coupling and SDS-D wave mixing are taken into account carefully. We adopt the complex scaling method to investigate the possible quasibound states, whose widths are from the three-body decay channel ΛcΛcπ\Lambda_c\Lambda_c\pi or ΛcΛˉcπ\Lambda_c\bar{\Lambda}_c\pi. For the double-charm system of I(JP)=1(1+)I(J^P)=1(1^+), we obtain a quasibound state, whose width is 0.50 MeV if the binding energy is -14.27 MeV. And the SS-wave ΛcΣc\Lambda_c\Sigma_c and ΛcΣc\Lambda_c\Sigma_c^* components give the dominant contributions. For the 1(0+)1(0^+) double-charm hexaquark system, we do not find any pole. We find more poles in the hidden-charm hexaquark system. We obtain one pole as a quasibound state in the IG(JPC)=1+(0)I^G(J^{PC})=1^+(0^{--}) system, which only has one channel (ΛcΣˉc+ΣcΛˉc)/2(\Lambda_c\bar{\Sigma}_c+\Sigma_c\bar{\Lambda}_c)/\sqrt{2}. Its width is 1.72 MeV with a binding energy of -5.37 MeV. But, we do not find any pole for the scalar 1(0+)1^-(0^{-+}) system. For the vector 1(1+)1^-(1^{-+}) system, we find a quasibound state. Its energies, widths and constituents are very similar to those of the 1(1+)1(1^+) double-charm case. In the vector 1+(1)1^+(1^{--}) system, we get two poles -- a quasibound state and a resonance. The quasibound state has a width of 0.6 MeV with a binding energy of -15.37 MeV. For the resonance, its width is 2.72 MeV with an energy of 63.55 MeV relative to the ΛcΣˉc\Lambda_c\bar{\Sigma}_c threshold. And its partial width from the two-body decay channel (ΛcΣˉcΣcΛˉc)/2(\Lambda_c\bar{\Sigma}_c-\Sigma_c\bar{\Lambda}_c)/\sqrt{2} is apparently larger than the partial width from the three-body decay channel ΛcΛˉcπ\Lambda_c\bar{\Lambda}_c\pi

    Resolving the RpAR_{\rm pA} and v2v_2 puzzle of D0D^0 mesons in pp-Pb collisions

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    It has been difficult to reconcile the experimental data on the D0D^0 meson nuclear modification factor and elliptic flow in pp-Pb collisions at LHC energies. Here we study these observables with the string melting version of a multi-phase transport model, which has been improved with the implementation of the Cronin effect (or transverse momentum broadening) and independent fragmentation for charm quarks. Using a strong Cronin effect allows us to provide the first simultaneous description of the D0D^0 meson RpAR_{\rm pA} and v2v_2 data at pTp_{\rm T} \leq 8 GeV/c/c. The model also provides a reasonable description of the D0D^0 meson pTp_{\rm T} spectra and the low-pTp_{\rm T} (below \sim 2 GeV/c/c) charged hadron spectra in p+pp+p and pp-Pb collisions as well as RpAR_{\rm pA} and v2v_2 in pp-Pb collisions. We find that both parton scatterings and the Cronin effect are important for the D0D^0 meson RpAR_{\rm pA}, while parton scatterings are mostly responsible for the D0D^0 meson v2v_2. Our results indicate that it is crucial to include the Cronin effect for the simultaneous description of the D0D^0 meson RpAR_{\rm pA} and v2v_2. Since the Cronin effect is expected to grow with the system size, this work implies that the Cronin effect could also be important for heavy hadrons in large systems.Comment: 6 pages, 3 figures, proceedings for the 11th International Conference on Hard and Electromagnetic Probes of High-Energy Nuclear Collision

    Features-Based Deisotoping Method for Tandem Mass Spectra

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    For high-resolution tandem mass spectra, the determination of monoisotopic masses of fragment ions plays a key role in the subsequent peptide and protein identification. In this paper, we present a new algorithm for deisotoping the bottom-up spectra. Isotopic-cluster graphs are constructed to describe the relationship between all possible isotopic clusters. Based on the relationship in isotopic-cluster graphs, each possible isotopic cluster is assessed with a score function, which is built by combining nonintensity and intensity features of fragment ions. The non-intensity features are used to prevent fragment ions with low intensity from being removed. Dynamic programming is adopted to find the highest score path with the most reliable isotopic clusters. The experimental results have shown that the average Mascot scores and F-scores of identified peptides from spectra processed by our deisotoping method are greater than those by YADA and MS-Deconv software

    Energy Efficiency of Generalized Spatial Modulation Aided Massive MIMO Systems

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    One of focuses in green communication studies is the energy efficiency (EE) of massive multiple-input multiple-output (MIMO) systems. Although the massive MIMO technology can improve the spectral efficiency (SE) of cellular networks by configuring a large number of antennas at base stations (BSs), the energy consumption of radio frequency (RF) chains increases dramatically. The increment of energy consumption is caused by the increase of RF chain number to match the antenna number in massive MIMO communication systems. To overcome this problem, a generalized spatial modulation (GSM) solution is presented to simultaneously reduce the number of RF chains and maintain the SE of massive MIMO communication systems. A EE model is proposed to estimate the transmission and computation power of massive MIMO communication systems with GSM. Simulation results demonstrate that the EE of massive MIMO communication systems with GSM outperforms the massive MIMO communication systems without GSM. Besides, the computation power consumed by massive MIMO communication systems with GSM is effectively reduced

    Augmented 2D-TAN: A Two-stage Approach for Human-centric Spatio-Temporal Video Grounding

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    We propose an effective two-stage approach to tackle the problem of language-based Human-centric Spatio-Temporal Video Grounding (HC-STVG) task. In the first stage, we propose an Augmented 2D Temporal Adjacent Network (Augmented 2D-TAN) to temporally ground the target moment corresponding to the given description. Primarily, we improve the original 2D-TAN from two aspects: First, a temporal context-aware Bi-LSTM Aggregation Module is developed to aggregate clip-level representations, replacing the original max-pooling. Second, we propose to employ Random Concatenation Augmentation (RCA) mechanism during the training phase. In the second stage, we use pretrained MDETR model to generate per-frame bounding boxes via language query, and design a set of hand-crafted rules to select the best matching bounding box outputted by MDETR for each frame within the grounded moment.Comment: Best Paper Award at the 3rd Person in Context (PIC) Challenge CVPR Workshop 202
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