Sökning: "Waveform relaxation"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Waveform relaxation.

1. 1. Electrothermal Simulation in a Concurrent Waveform Relaxation Based Circuit Simulator

   Författare :Magnus Wiklund; Institutionen för elektro- och informationsteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Circuit synthesis; Bond graphs; Nullor; Circuit theory; Analog simulation; Circuit simulation; Multiprocessor computer; CONCISE; Parallel computation; Waveform relaxation; Thermal models; Transistor models; Electro-thermal simulation; Electro-thermal modeling; Translinear circuits; Electronics; Elektronik; Electrical engineering; Elektroteknik;

   Sammanfattning : The main purpose of this work is to study methods to simulate electro-thermal effects in integrated circuits using CONCISE a waveform relaxation based circuit simulator. WR is a method that is suitable to run on a multi-computer with state of the art computing power. Especially CMOS VLSI circuits have been simulated successfully with WR. LÄS MER

3. 2. Adaptive time-integration for goal-oriented and coupled problems

   Författare :Peter Meisrimel; Numerisk analys; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; time-adaptivity; goal-oriented problems; error estimation; coupled problems; waveform relaxation; asynchronous methods; conjugate heat transfer;

   Sammanfattning : We consider efficient methods for the partitioned time-integration of multiphysics problems, which commonly exhibit a multiscale behavior, requiring independent time-grids. Examples are fluid structure interaction in e.g., the simulation of blood-flow or cooling of rocket engines, or ocean-atmosphere-vegetation interaction. LÄS MER

4. 3. Contributions to Numerical Solution of Stochastic Differential Equations

   Författare :Anders Muszta; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; adaptive method; change of time; CIR model; CKLS model; convergence order; Euler method; heavy-tailed SDE; hyperbolic SDE; geometric integration; global Lipschitz condition; Levy process; Lie group method; local Lipschitz condition; local martingales; mean reversion; Milstein method; numerical method; semimartingale; stochastic differential equation; stochastic Taylor expansion; strong approximation; symplectic integration; volatility induced stationarity; waveform relaxation; volatility induced stationarity;

   Sammanfattning : This thesis consists of four papers: Paper I is an overview of recent techniques in strong numerical solutions of stochastic differential equations, driven by Wiener processes, that have appeared the last then 10 years, or so. Paper II studies theoretical and numerical aspects of stochastic differential equations with so called volatility induced stationarity. LÄS MER

5. 4. Partitioned methods for time-dependent thermal fluid-structure interaction

   Författare :Azahar Monge; Numerisk analys; []
   Nyckelord :thermal FSI; Conjugate heat transfer; Domain decomposition; Time adaptivity; Coupled problems; multirate;

   Sammanfattning : The efficient simulation of thermal interaction between fluids and structures is crucial in the design of many industrial products, e.g. turbine blades or rocket nozzles. LÄS MER

7. 5. Characterization of Electrical Insulation Exposed to Arbitrary Voltage Waveforms

   Författare :Björn Sonerud; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; arbitrary voltage waveforms; partial discharge; diagnostics; dielectric response measurement; signal processing; electrical treeing; dielectric heating.;

   Sammanfattning : The extensive use of power electronics in power systems today gives rise to other voltage waveforms than the conventional 50/60 Hz sinusoidal and consequently other types of electric stress act on high voltage insulating materials. Previous studies has shown that Pulse Width Modulated (PWM) voltages and similar waveforms increase stress in Adjustable Speed Drives (ASD) as compared with sinusoidal waveforms and it has also been shown that partial discharge (PD) activity is intensified during PWM voltages and that rise time of square like pulses affect PD inception voltage. LÄS MER