Numerical optimization for Artificial Retina Algorithm

High-energy physics experiments rely on reconstruction of the trajectories of particles produced at the interaction point. This is a challenging task, especially in the high track multiplicity environment generated by p-p collisions at the LHC energies. A typical event includes hundreds of signal examples (interesting decays) and a significant amount of noise (uninteresting examples). This work describes a modification of the Artificial Retina algorithm for fast track finding: numerical optimization methods were adopted for fast local track search. This approach allows for considerable reduction of the total computational time per event. Test results on simplified simulated model of LHCb VELO (VErtex LOcator) detector are presented. Also this approach is well-suited for implementation of paralleled computations as GPGPU which look very attractive in the context of upcoming detector upgrades

Numerical optimization of passive chaotic micromixers

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Due to the lack of turbulence in micromixers diffusion is the main process contributing to microfluidic mixing. Especially mixing of uids with low diffusivity is a difficult task. The recently discovered mechanism of "chaotic-advection" enhances the diffusion process by stretching and folding the fluid interfaces in order to provide a larger interface. Certain passive micromixers like the staggered herringbone mixer (SHM) apply this concept and succeed in enhancing the mixing process considerably. The optimization of such micromixers is a time consuming and often expensive process. We demonstrate that the application of the lattice Boltzmann (LB) method to study advection and diffusion processes can be an efficient tool to optimize micromixers. By combining finite time Lyapunov exponents to study chaotic advection and Danckwert's intensity of segregation to study the diffusion, we demonstrate how optimal geometrical parameters for the SHM can be found and how diffusion is improved by the complex ow pattern inside the mixer. The current article provides a review of our results published in [1] together with additional studies on modelling diffusive mixing with the LB method.This work was financed within the DFG priority program "nano- and microfluidics", the DFG collaborative research center 716, and by the NWO/STW VIDI grant of J. Harting

Aerodynamic design using numerical optimization

The procedure of using numerical optimization methods coupled with computational fluid dynamic (CFD) codes for the development of an aerodynamic design is examined. Several approaches that replace wind tunnel tests, develop pressure distributions and derive designs, or fulfill preset design criteria are presented. The method of Aerodynamic Design by Numerical Optimization (ADNO) is described and illustrated with examples

Solving Dynamic Stochastic Optimization Problems Using the Method of Endogenous Gridpoints

Numerical Optimization; Dynamic Programming; Precautionary Saving

Transonic rotor tip design using numerical optimization

The aerodynamic design procedure for a new blade tip suitable for operation at transonic speeds is illustrated. For the first time, 3 dimensional numerical optimization was applied to rotor tip design, using the recent derivative of the ROT22 code, program R22OPT. Program R22OPT utilized an efficient quasi-Newton optimization algorithm. Multiple design objectives were specified. The delocalization of the shock wave was to be eliminated in forward flight for an advance ratio of 0.41 and a tip Mach number of 0.92 at psi = 90 deg. Simultaneously, it was sought to reduce torque requirements while maintaining effective restoring pitching moments. Only the outer 10 percent of the blade span was modified; the blade area was not to be reduced by more than 3 percent. The goal was to combine the advantages of both sweptback and sweptforward blade tips. A planform that featured inboard sweepback was combined with a sweptforward tip and a taper ratio of 0.5. Initially, the ROT22 code was used to find by trial and error a planform geometry which met the design goals. This configuration had an inboard section with a leading edge sweep of 20 deg and a tip section swept forward at 25 deg; in addition, the airfoils were modified