546 research outputs found
Extraction of Top Backgrounds in the Higgs Boson Search with the Decay with a Full-Jet Veto at the LHC
The search for a Standard Model Higgs boson with the decay and the application of a full-jet veto
yields a strong sensitivity in the mass range GeV. One of the
residual backgrounds is related to processes involving top quarks. A method for
the extraction of top backgrounds is evaluated at the parton and hadronic
levels based on the data-driven extraction of the jet veto survival
probability. The uncertainty of the proposed method is about 15%.Comment: 7 pages, 4 tables, v3 fixes a macro issue in the metadata, published
version in Phys. Rev.
Particle Swarm Algorithm to Optimize LSTM Short-Term Load Forecasting
Accurate load forecasting is of great significance for national and grid planning and management. In order to improve the accuracy of short-term load forecasting, an LSTM prediction model based on particle swarm optimization (PSO)algorithm is proposed. LSTM has the characteristics of avoiding gradient disappearance and gradient explosion, but there is a problem that parameters are difficult to select. Therefore, particle swarm optimization algorithm is used to help it select parameters. The experimental results show that the optimized LSTM has higher prediction accuracy
A Two-phase Simulation of Wave Impact on a Horizontal Deck Based on SPH Method
AbstractIn this paper, a two-phase numerical model is developed to study the effect of the gas phase in problems of wave attacking deck. The model is based on weakly compressible smoothed particles hydrodynamics (WCSPH) method, and is implemented in C++ and CUDA language to running on GPUs starting from DualSPHysics. Surface tension is considered by incorporating the surface tension force into the momentum equations. Therefore, the continuum surface force (CSF) model is proposed to eliminating the interphase particle penetrations. To calculate surface tension force at interfaces, a color function is assigned to each particle from different phases. Furthermore, to enhance the robustness of this method, the assigned color function is smoothed by calculating the weighted averaging value of initial color function on its support domain. The simulation results are compared with experiment results. The point pressure from numerical results shows well agreement with experimental ones, and is more accurate than one phase simulation. The reason is lying on its satisfying on the condition of air pressure
Provably Robust Semi-Infinite Program Under Collision Constraints via Subdivision
We present a semi-infinite program (SIP) solver for trajectory optimizations
of general articulated robots. These problems are more challenging than
standard Nonlinear Program (NLP) by involving an infinite number of non-convex,
collision constraints. Prior SIP solvers based on constraint sampling cannot
guarantee the satisfaction of all constraints. Instead, our method uses a
conservative bound on articulated body motions to ensure the solution
feasibility throughout the optimization procedure. We further use subdivision
to adaptively reduce the error in conservative motion estimation. Combined, we
prove that our SIP solver guarantees feasibility while approaches the critical
point of SIP problems up to arbitrary user-provided precision. We have verified
our method on a row of trajectory optimization problems involving industrial
robot arms and UAVs, where our method can generate collision-free, locally
optimal trajectories within a couple minutes
Determination of Temperature-Dependent Stress State in Thin AlGaN Layer of AlGaN/GaN HEMT Heterostructures by Near-Resonant Raman Scattering
The temperature-dependent stress state in the AlGaN barrier layer of AlGaN/GaN heterostructure grown on sapphire substrate was investigated by ultraviolet (UV) near-resonant Raman scattering. Strong scattering peak resulting from the A1(LO) phonon mode of AlGaN is observed under near-resonance condition, which allows for the accurate measurement of Raman shifts with temperature. The temperature-dependent stress in the AlGaN layer determined by the resonance Raman spectra is consistent with the theoretical calculation result, taking lattice mismatch and thermal mismatch into account together. This good agreement indicates that the UV near-resonant Raman scattering can be a direct and effective method to characterize the stress state in thin AlGaN barrier layer of AlGaN/GaN HEMT heterostructures
Application of an ultrasound-guided bilateral erector spinae plane block after the Nuss procedure for pectus excavatum in children: a retrospective cohort study with propensity score matching
ObjectiveTo retrospectively analyze the effect of applying an ultrasound-guided bilateral erector spine plane block (ESPB) after the Nuss procedure for surgical repair of pectus excavatum (PE) in children.MethodsThe subjects of the study were patients with severe PE who received the Nuss procedure in our hospital between 1 January 2019 and 30 November 2021. According to different methods for postoperative pain management, the enrolled patients were divided into two groups, the ultrasound-guided ESPB group and the thoracic epidural analgesia (TEA) group. The primary outcome of this study was analgesic drug dosage and the secondary outcome was numerical rating scales (NRSs) between the two groups.ResultsThere was no significant difference between the two groups in terms of demographic, preoperative clinical evaluation, or surgical characteristics (P > 0.05). The catheter duration in the TEA group was significantly shorter than that in the ESPB group (P < 0.05), while the hospitalization time in the ESPB group was significantly shorter than that in the TEA group (P < 0.05). In terms of oral morphine equivalent comparison, the required dose of the TEA group was lower than that of the ESPB group on the 1st and 2nd day after the operation (P < 0.05), and there was no statistical difference between the two groups on the 3rd and 4th day after the operation (P > 0.05). The number of patients with an S-NRS ≥ 7 and D-NRS ≥ 7 in the TEA group at day 1 was lower than that in the ESPB group (P < 0.05). There was no significant difference between the two groups at other time points (P > 0.05),ConclusionAn ultrasound-guided ESPB used in Nuss surgery for children with funnel chest can provide good analgesia for surgery and shorten the postoperative rehabilitation and hospitalization time of patients. It is a safe and effective alternative to TEA
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