We introduce an approach to carry out layout optimization of metallic antenna parts. An technique first developed for the load-bearing elastic structures is adapted purpose design. The local conductivity values in a given region are used as design variables and iteratively updated by gradient-based algorithm. Given set time-domain signals from exterior sources, objective here maximize energy received transmitted coaxial cable. proceeds through sequence coarsely-defined lossy designs with...

The acoustic black hole (ABH) effect in waveguides is studied using frequency-domain finite element simulations of a cylindrical waveguide with an embedded ABH termination composed retarding rings. This design adopted from experimental study the literature, which surprisingly showed, contrary to structural counterpart, that addition damping material end does not significantly reduce reflection coefficient any further. To investigate this unexpected behavior, we model different mechanisms...

The waveguide acoustic black hole (WAB) effect is a promising approach for controlling wave propagation in various applications, especially attenuating sound waves. While the wave-focusing of structural holes has found widespread classical ribbed design (WABs) acts more as resonance absorber than true device. In this study, we employ computational optimization to achieve conceptual WAB with enhanced properties. We investigate influence viscothermal boundary losses on process by formulating...

We show how the computational power and programmability of modern graphics processing units (GPUs) can be used to efficiently solve large-scale pixel-based material distribution problems using a gradient-based optimality criterion method. To illustrate principle, so-called topology optimization problem that results in constrained nonlinear programming with over 4 million decision variables is solved on commodity GPU.

We present an approach to design from scratch planar microwave antennas for the purpose of ultra-wideband (UWB) near-field sensing. Up about 120 000 variables associated with square grids on substrates are subject design, and a numerical optimization algorithm decides, after around 200 iterations, each edge in grid whether it should consist metal or dielectric. The antenna layouts produced this show UWB impedance matching properties coupling coefficients that Hat over much wider frequency...

In this paper, we investigate the use of fat tissue as a communication channel between in-body, implanted devices at R-band frequencies (1.7⁻2.6 GHz). The proposed is based on an anatomical model human body. We propose novel probe that optimized to efficiently radiate into tissue. our evaluate path loss by studying transmission coefficient over frequencies. conduct extensive simulation studies and validate results experimentation phantom ex-vivo porcine tissue, with good agreement...

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed traversing rough terrain. While related research primarily focuses on lightweight robots electric motors and fast actuation, this study uses forestry complex hydraulic driveline slow actuation. simulate the using multibody dynamics apply system identification to find an appropriate set simulation parameters. then train policies in various techniques mitigate gap,...

Solar activity significantly influences the Earth's magnetosphere and ionosphere, causing current systems space weather effects. The interaction between rapidly changing magnetic field Earth’s conductivity induces an electric at surface producing Geomagnetically Induced Currents (GICs) within critical human infrastructure, posing a risk of damage to power lines.GICs strongly depend on ground conductivity. Sweden has large spatial variations complexity in underlying structure across...

In large scale data centers, a single fault can lead to correlated failures of several physical machines and the tasks running on them, simultaneously. Such severely damage reliability service or job. This paper models impact stochastic job in center. We focus caused by power outages network components, jobs multiple replicas identical tasks. present statistical model an approximation technique for computing job's presence failures. addition, we address problem scheduling with constraints....

This article utilizes a topology optimization approach to design planar multilayer transitions between substrate integrated waveguides (SIWs) and rectangular (RWGs). The problem is formulated based on the modal field analyses Maxwell's equations in time domain solved by finite-difference time-domain (FDTD) method. We present boundary condition Klein-Gordon equation split traveling waves at homogeneous waveguide ports. employ compute portal quantities devise an adjoint-field system that...

The archetypical topology optimization problem concerns designing the layout of material within a given region space so that some performance measure is extremized. To improve manufacturability and reduce manufacturing costs, restrictions on possible layouts may be imposed. Among such restrictions, constraining minimum length scales different regions design has significant place. Within density filter based framework most commonly used definition scale not less than D if any point lies...

Material distribution topology optimization problems are generally ill-posed if no restriction or regularization method is used. To deal with these issues, filtering procedures routinely applied. In a recent paper, we presented framework that encompasses the vast majority of currently available density filters. this show nonlinear filters ensure existence solutions to continuous version minimum compliance problem. addition, provide detailed description on how efficiently compute...

We consider techniques that enable large-scale gradient-based shape optimization of wave-guiding devices in the context three-dimensional time-domain simulations. The approach relies on a memory efficient boundary representation gradient together with primal and adjoint solvers semiautomatically generated by FEniCS framework. hyperbolic character governing linear wave equation, written as first-order system, is exploited through systematic use characteristic decomposition both to define...

A new formulation is presented that extends the material distribution topology optimization method to address boundary-effect-dominated problems, where specific boundary conditions need be imposed at solid–fluid interfaces. As an example of such a problem, we focus on design acoustic structures with significant viscous and thermal losses. In various applications, especially for acoustically small devices, main portion viscothermal dissipation occurs in so-called layer. One way accounting...

Efficient mapping of Virtual Machines~(VMs) onto physical servers is a key problem for cloud infrastructure providers as hardware utilization directly impacts profit. Today, this commonly only performed when new VMs are created, but VM workloads fluctuate and server availability varies, any initial bound to become suboptimal over time. We introduce set heuristic methods continuous optimization the VM-to-server based on combinations fundamental management actions, namely suspending resuming...