Remapping Between Meshes with Isoparametric Cells:a Case Study

We explore an intersection-based remap method between meshes consisting of isoparametric elements.We present algorithms for the case of serendipity isoparametric elements(QUAD8 elements)and piece-wise constant(cell-centered)discrete fields.We demonstrate convergence properties of this remap method with a few numerical experiments.

RKDG Methods with Multi-resolution WENO Limiters for Solving Steady-State Problems on Triangular Meshes

In this paper, we design high-order Runge-Kutta discontinuous Galerkin (RKDG) methods with multi-resolution weighted essentially non-oscillatory (multi-resolution WENO) limiters to compute compressible steady-state problems on triangular meshes. A troubled cell indicator extended from structured meshes to unstructured meshes is constructed to identify triangular cells in which the application of the limiting procedures is required. In such troubled cells, the multi-resolution WENO limiting methods are used to the hierarchical L^(2) projection polynomial sequence of the DG solution. Through using the RKDG methods with multi-resolution WENO limiters, the optimal high-order accuracy can be gradually reduced to first-order in the triangular troubled cells, so that the shock wave oscillations can be well suppressed. In steady-state simulations on triangular meshes, the numerical residual converges to near machine zero. The proposed spatial reconstruction methods enhance the robustness of classical DG methods on triangular meshes. The good results of these RKDG methods with multi-resolution WENO limiters are verified by a series of two-dimensional steady-state problems.

基于TD-OFDM的MESH自组网络广播信道设计方法

针对Wi-Fi MESH各节点发送数据时会发生丢包的现象,导致通信传输可靠性不高的问题,提出了一种基于TDOFDM的MESH自组网络广播信道设计方法。首先,进行帧结构设计,设计广播子帧和数据子帧的结构。接着,进行时间同步,同步完成后数据在物理层进行一系列流程,完成整个广播信道的设计。经过仿真,实验结果表明将物理广播信道加入MESH组网后对比基于Wi-Fi的MESH组网,自组网碰撞和重传大大减少,正确接收码字的概率提升了18.6%,提高了通信传输的可靠性。

Effect of Types and Orders of Electromagnetic Field Finite Element Meshes on Power Communication Harmonic Parameters Calculation Results of Tubular Hydrogenerators

In generator design field,waveform total harmonic distortion(THD)and telephone harmonic factor(THF)are parameters commonly used to measure the impact of generator no-load voltage harmonics on the power communication quality.Tubular hydrogenerators are considered the optimal generator for exploiting low-head,high-flow hydro resources,and they have seen increasingly widespread application in China's power systems recent years.However,owing to the compact and constrained internal space of such generators,their internal magnetic-field harmonics are pronounced.Therefore,accurate calculation of their THD and THF is crucial during the analysis and design stages to ensure the quality of power communication.Especially in the electromagnetic field finite element modeling analysis of such generators,the type and order of the finite element meshes may have a significant impact on the THD and THF calculation results,which warrants in-depth research.To address this,this study takes a real 34 MW large tubular hydrogenerator as an example,and establishes its electromagnetic field finite element model under no-load conditions.Two types of meshes,five mesh densities,and two mesh orders are analyzed to reveal the effect of electromagnetic field finite element mesh types and orders on the calculation results of THD and THF for such generators.

Analysis of Micromechanical Properties at the Interface of Pre-wet SBS Modified Asphalt Mixture Based on Molecular Simulation Technology

The pre-wetting of aggregate surface is a means to improve the interface performance of SBS modified asphalt and aggregate.The effect of pre-wetting technology on the interaction between SBS modified asphalt and aggregate was analyzed by molecular dynamics simulation.The diffusion coefficient and concentration distribution of SBS modified asphalt on aggregate surface are included.The simulation results show that the diffusion coefficient of the aggregate surface of SBS modified asphalt is increased by 47.6%and 70.5%respectively after 110#asphalt and 130#asphalt are pre-wetted.The concentration distribution of SBS modified asphalt on the aggregate surface after pre-wetting is more uniform.According to the results of interface energy calculation,the interface energy of SBS modified bitumen and aggregate can be increased by about 5%after pre-wetting.According to the results of molecular dynamics simulation,the pre-wetting technology can effectively improve the interface workability of SBS modified bitumen and aggregate,so as to improve the interface performance.

Ultra‑Transparent and Multifunctional IZVO Mesh Electrodes for Next‑Generation Flexible Optoelectronics

Mechanically durable transparent electrodes are essential for achieving long-term stability in flexible optoelectronic devices.Furthermore,they are crucial for applications in the fields of energy,display,healthcare,and soft robotics.Conducting meshes represent a promising alternative to traditional,brittle,metal oxide conductors due to their high electrical conductivity,optical transparency,and enhanced mechanical flexibility.In this paper,we present a simple method for fabricating an ultra-transparent conducting metal oxide mesh electrode using selfcracking-assisted templates.Using this method,we produced an electrode with ultra-transparency(97.39%),high conductance(Rs=21.24Ωsq^(−1)),elevated work function(5.16 eV),and good mechanical stability.We also evaluated the effectiveness of the fabricated electrodes by integrating them into organic photovoltaics,organic light-emitting diodes,and flexible transparent memristor devices for neuromorphic computing,resulting in exceptional device performance.In addition,the unique porous structure of the vanadium-doped indium zinc oxide mesh electrodes provided excellent flexibility,rendering them a promising option for application in flexible optoelectronics.

基于蓝牙Mesh的智能车位检测控制系统设计与实现

为解决老旧停车场更新停车管理系统成本高、维修困难、能耗大等问题,设计了基于蓝牙Mesh本地组网和云端服务器的智能车位检测系统。该系统具有低能耗、维修简便、安装成本低、操作简单等优点。选择了功耗低、价格实惠的超声波监测技术,并详细设计了硬件和软件方案,实现了精确的车位检测和数据传输功能。经过软硬件测试,结果显示该系统运行稳定可靠,通信性能优良,维护成本低。这一设计为未来智能停车场管理提供了创新的解决方案。

基于SJ-RW算法的城市灾害应急无线mesh网构建

目前国内外城市自然灾害频发,应急无线mesh网络由于其优越性,非常适合应用于城市灾害应急通信中。但如何合理分割运用频谱资源,快速接入网络仍是亟待解决的难题。盲汇聚是一种基于信道跳变技术的信道汇聚方法,本研究引入一种快速汇聚全分集的SJ-RW(Sender jump-receiver wait)盲汇聚算法,构建了基于SJ-RW盲汇聚的城市灾害应急通信无线mesh网络。以某城市洪涝灾害下复杂环境应急无线通信为例,进行实证分析。研究结果表明,本研究构建的新型应急无线mesh网络在城市洪涝灾害应急通信应用中,在最大汇聚时间间隔和平均汇聚时间间隔等参数上,相对于传统网络,具有明显优越性,且能够更快实现信道汇聚,提高信道频率利用率。研究成果可为解决城市灾害应急通信问题提供一种新的思路和方法。

PARALLEL COMPUTATION OF 3-D HYPERSONIC FLOWS ON UNSTRUCTURED HYBRID MESHES

A parallel virtual machine （PVM） protocol based parallel computation of 3-D hypersonic flows with chemical non-equilibrium on hybrid meshes is presented. The numerical simulation for hypersonic flows with chemical non-equilibrium reactions encounters the stiffness problem, thus taking huge CPU time. Based on the domain decomposition method, a high efficient automatic domain decomposer for three-dimensional hybrid meshes is developed, and then implemented to the numerical simulation of hypersonic flows. Control equations are multicomponent N-S equations, and spatially discretized scheme is used by a cell-centered finite volume algorithm with a five-stage Runge-Kutta time step. The chemical kinetic model is a seven species model with weak ionization. A point-implicit method is used to solve the chemical source term. Numerical results on PC-Cluster are verified on a bi-ellipse model compared with references.

基于强化学习的大规模多模Mesh网络联合路由选择及资源调度算法

为了平衡新型电力系统中大规模多模Mesh网络的传输可靠性和效率,该文在对优化问题进行描述和分析的基础上提出一种基于强化学习的大规模多模Mesh网络联合路由选择及资源调度算法,分为两个阶段。在第1阶段中,根据网络拓扑结构信息和业务需求,利用一种多条最短路径路由算法,输出所有最短路径。在第2阶段中,提出一种基于多臂老虎机(MAB)的资源调度算法,该算法基于得到的最短路径集合构建MAB的摇臂,然后根据业务需求计算回报,最终给出最优的路由选择及资源调度方式用于业务传输。仿真结果表明,所提算法能够满足不同的业务传输需求,实现端到端路径的平均时延和平均传输成功率的高效平衡。

基于蓝牙Mesh技术的校园绿化浇灌系统设计

调研发现,很多高校对校园绿化管理手段有限,虽投入大量人力、物力,但经济效益差,水资源浪费现象比较突出。基于此,设计了一种以传感器+单片机为终端控制单元、利用蓝牙Mesh组网通信的校园绿化浇灌系统。系统具有组网便捷、覆盖面广、控制灵活、网络健壮性强等优点。实验结果表明:系统在不同的环境因素下,能自主判断植物需求,按照既定策略实施浇灌,系统运行正确率平均达91%。将该系统在高校推广使用,能有效降低后勤运营成本,节约水资源,提高校园绿化养护效率。

Three-dimensional magnetotellurics modeling using edgebased finite-element unstructured meshes

Three-dimensional forward modeling magnetotellurics （MT） problems. We present a is a challenge for geometrically complex new edge-based finite-element algorithm using an unstructured mesh for accurately and efficiently simulating 3D MT responses. The electric field curl-curl equation in the frequency domain was used to deduce the H （curl） variation weak form of the MT forward problem, the Galerkin rule was used to derive a linear finite-element equation on the linear-edge tetrahedroid space, and, finally, a BI-CGSTAB solver was used to estimate the unknown electric fields. A local mesh refinement technique in the neighbor of the measuring MT stations was used to greatly improve the accuracies of the numerical solutions. Four synthetic models validated the powerful performance of our algorithms. We believe that our method will effectively contribute to processing more complex MT studies.

蓝牙Mesh网络AODV路由改进算法

蓝牙Mesh网络使用泛洪进行多跳通信,在没有路由机制的情况下,由于消息的连续广播,原有泛洪机制会导致网络开销增大和通信延迟。本文基于能量有效的AODV改进算法E AODV使用MATLAB进行仿真,根据跳数、节点剩余能量、链路质量来选择最优节点进行数据包的转发。仿真结果表明,E-AODV算法可减小蓝牙Mesh网络中RREQ数据包传输数量,通过与传统泛洪、AODV算法比较,该算法能够有效降低数据包传输时延,降低网络能耗,提高网络性能。

软件定义无线Mesh网络多目标路由优化算法

无线Mesh网络(Wireless Mesh network, WMN)中,链路拥塞会导致较长的传输时延和排队时间,因此将链路负载均衡与服务质量结合起来一直是研究热点.本文针对多目标路由优化管理的关键问题,将路由问题表述为整数线性规划(Integer linear programming, ILP)模型,并将无线Mesh网络与软件定义网络(Software defined network, SDN)结合,设计了适应于SD-WMN架构的多目标函数、约束条件以及整体的网络优化模型,此外,由于该整数线性规划模型是NP完全的,本文将改进的人工蜂群的启发式优化算法引入到路由优化算法中,以获得源节点和目的节点之间传输流量的理想路径.本文所提出方法在Mininet网络模拟工具中的仿真结果证明了该算法的有效性,与OSPF、SDNR以及遗传蚁群优化(G-ACO)相比,所提出方法在丢包率、往返时间和负载均衡方面均有不错的改善.

矿用无线Mesh自组网基站设计

针对矿难事故发生后井下通信系统瘫痪、井下救援人员无法与前方指挥部及时沟通和进行音视频信息交互的问题,设计了一种矿用无线Mesh自组网基站。该基站采用无线Mesh自组网通信技术,以FPGA+ARM为控制芯片、AD9361为射频芯片,采用ARM处理系统模块、可编程逻辑模块、射频模块、AXI总线模块搭建硬件平台,最后对电源模块进行本质安全设计。测试结果表明,该基站满足井下的应急通信要求。

Use of biological meshes for abdominal wall reconstruction in highly contaminated fields

Abdominal wall defects and incisional hernias represent a challenging problem. In particular, when a synthetic mesh is applied to contaminated wounds, its removal is required in 50%-90% of cases. Biosynthetic meshes are the newest tool available to surgeons and they could have a role in ventral hernia repair in a potential-ly contaminated field. We describe the use of a sheet of bovine pericardium graft in the reconstruction of abdominal wall defect in two patients. Bovine pericardium graft was placed in the retrorectus space and secured to the anterior abdominal wall using polypropylene sutures in a tension-free manner. We experienced no evidence of recurrence at 4 and 5 years follow-up.

动态环境下无线Mesh网络的路由器节点部署

在无线Mesh网络(Wireless Mesh network,WMN)中,Mesh路由器(Mesh router,MR)的节点部署对于网络性能有很大的影响.尤其是当Mesh客户端(Mesh client,MC)是动态移动时,MR会根据动态网络拓扑调整其位置,这种动态环境下所带来的能耗问题以及节点的负载均衡问题都变得更加难以解决.本文提出一种应用模拟退火(Stimulated annealing,SA)算法与差分进化(Differential evolution,DE)算法的混合优化算法DY-DESA来处理动态环境下的路由器节点部署问题.部署这些路由器时考虑的性能指标是客户端覆盖率、网络连通性以及节点的负载均衡指数.仿真结果表明,运用新提出的算法对无线Mesh网络中路由器节点进行部署,其在客户端覆盖率、网络连通性以及节点的负载均衡指数等方面都有所提升.

面向算力网络的全光网MESH化组网规划研究

全光承载网络是算力网络的根基和底座,面向算力网络的业务发展需求将呈现MESH化组网的趋势。在分析算力网络对光网络需求的基础上,对比了全光网MESH化组网和传统组网的差异,进而研究全光网络MESH化组网规划思路与规划重点,最后提出了全光网MESH化部署相关建议,以期更好地助力算力网络新发展。

Use of absorbable meshes in laparoscopic paraesophageal hernia repair

Paraesophageal hernia(PEH)repair is one of the most challenging upper gastrointestinal operations.Its high rate of recurrence is due mostly to the low quality of the crura and size of the hiatal defect.In an attempt to diminish the recurrence rates,some clinical investigators have begun performing meshreinforced cruroplasty with nonabsorbable meshes like polypropylene or polytetrafluoroethylene.The main problem with these materials is the occurrence,in some patients,of serious mesh-related morbidities,such as erosions into the stomach and the esophagus,some of which necessitate subsequent esophagectomy or gastrectomy.Absorbable meshes can be synthetic or biological and were introduced in recent years for PEH repair with the intent of diminishing the recurrence rates observed after primary repair alone but,theoretically,without the risks of morbidities presented by the nonabsorbable meshes.The current role of absorbable meshes in PEH repair is still under debate,since there are few data regarding their long-term efficacy,particularly in terms of recurrence rates,morbidity,need for revision,and quality of life.In this opinion review,we analyze all the presently available evidence of reinforced cruroplasty for PEH repair using nonabsorbable meshes(synthetic or biological),focusing particularly on recurrence rates,mesh-related morbidity,and long-term quality of life.

Superconvergence analysis of Wilson element on anisotropic meshes

The Wilson finite element method is considered to solve a class of two- dimensional second order elliptic boundary value problems. By using of the particular structure of the element and some new techniques, we obtain the superclose and global superconvergence on anisotropic meshes. Numerical example is also given to confirm our theoretical analysis.