scholarly journals Multi-boson block factorization of fermions

2018 ◽  
Vol 175 ◽  
pp. 01003 ◽  
Author(s):  
Leonardo Giusti ◽  
Marco Cè ◽  
Stefan Schaefer
Keyword(s):  
Monte Carlo ◽  
Lattice Qcd ◽  
Form Factors ◽  
Quark Propagator ◽  
Monte Carlo Integration ◽  
Integration Schemes ◽  
Block Factorization ◽  
Boson Fields ◽  
Multi Level ◽  
The Impact

The numerical computations of many quantities of theoretical and phenomenological interest are plagued by statistical errors which increase exponentially with the distance of the sources in the relevant correlators. Notable examples are baryon masses and matrix elements, the hadronic vacuum polarization and the light-by-light scattering contributions to the muon g – 2, and the form factors of semileptonic B decays. Reliable and precise determinations of these quantities are very difficult if not impractical with state-of-the-art standard Monte Carlo integration schemes. I will review a recent proposal for factorizing the fermion determinant in lattice QCD that leads to a local action in the gauge field and in the auxiliary boson fields. Once combined with the corresponding factorization of the quark propagator, it paves the way for multi-level Monte Carlo integration in the presence of fermions opening new perspectives in lattice QCD. Exploratory results on the impact on the above mentioned observables will be presented.

scholarly journals QMC designs: Optimal order Quasi Monte Carlo integration schemes on the sphere

2014 ◽  
Vol 83 (290) ◽  
pp. 2821-2851 ◽  
Author(s):  
J. S. Brauchart ◽  
E. B. Saff ◽  
I. H. Sloan ◽  
R. S. Womersley
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Integration ◽  
Optimal Order ◽  
Quasi Monte Carlo ◽  
Integration Schemes

scholarly journals Impact of Scalar Leptoquarks on Heavy Baryonic Decays

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
K. Azizi ◽  
A. T. Olgun ◽  
Z. Tavukoğlu
Keyword(s):  
Experimental Data ◽  
Standard Model ◽  
Lattice Qcd ◽  
Light Cone ◽  
Branching Ratio ◽  
Form Factors ◽  
Full Theory ◽  
The Standard Model ◽  
The Impact ◽  
Scalar Leptoquarks

We present a study on the impact of scalar leptoquarks on the semileptonic decays of Λb, Σb, and Ξb. To this end, we calculate the differential branching ratio and lepton forward-backward asymmetry defining the processes Λb→Λl+l-, Σb→Σl+l-, and Ξb→Ξl+l-, with l being μ or τ, using the form factors calculated via light cone QCD in full theory. In calculations, the errors of form factors are taken into account. We compare the results obtained in leptoquark model with those of the standard model as well as the existing lattice QCD predictions and experimental data.

scholarly journals Application of a Monte Carlo Procedure for Probabilistic Fatigue Design of Floating Offshore Wind Turbines

2017 ◽  
Author(s):  
Kolja Müller ◽  
Po Wen Cheng
Keyword(s):  
Monte Carlo ◽  
Wind Turbines ◽  
Environmental Conditions ◽  
Measurement Data ◽  
Monte Carlo Integration ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Sampling Procedures ◽  
The Impact

Abstract. Fatigue load assessment of floating offshore wind turbines poses new challenges on the feasibility of numerical procedures. Due to the increased sensitivity of the considered system with respect to the environmental conditions from wind and ocean, the application of common procedures used for fixed-bottom structures results in either inaccurate simulation results or hard-to-quantify conservatism in the system design. Monte Carlo based sampling procedures provide a more realistic approach to deal with the large variation of the environmental conditions, although basic randomization has shown slow convergence. Specialized sampling methods allow efficient coverage of the complete design space, resulting in faster convergence and hence a reduced number of required simulations. In this study, a quasi-random sampling approach based on Sobol’ sequences is applied to select representative events for the determination of the lifetime damage. This is calculated applying Monte-Carlo integration, using subsets of a resulting total of 16 200 coupled time-domain simulations performed with the simulation code FAST. The considered system is the DTU 10 MW reference turbine installed on the LIFES50+ OO-Star Wind Floater Semi 10 MW floating platform. Statistical properties of the considered environmental parameters (i.e. wind speed, wave height and wave period) are determined based on the measurement data from Gulf of Maine, USA. Convergence analyses show that it is sufficient to perform around 200 simulations in order to reach less than 10 % uncertainty of lifetime fatigue damage equivalent loading. Complementary in-depth investigation is performed focusing on the load sensitivity and the impact of outliers. Recommendations for the implementation of the proposed methodology in the design process are also provided.

scholarly journals Application of a Monte Carlo procedure for probabilistic fatigue design of floating offshore wind turbines

2018 ◽  
Vol 3 (1) ◽  
pp. 149-162 ◽  
Author(s):  
Kolja Müller ◽  
Po Wen Cheng
Keyword(s):  
Monte Carlo ◽  
Wind Turbines ◽  
Environmental Conditions ◽  
Measurement Data ◽  
Monte Carlo Integration ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines ◽  
Sampling Procedures ◽  
The Impact

Abstract. Fatigue load assessment of floating offshore wind turbines poses new challenges on the feasibility of numerical procedures. Due to the increased sensitivity of the considered system with respect to the environmental conditions from wind and ocean, the application of common procedures used for fixed-bottom structures results in either inaccurate simulation results or hard-to-quantify conservatism in the system design. Monte Carlo-based sampling procedures provide a more realistic approach to deal with the large variation in the environmental conditions, although basic randomization has shown slow convergence. Specialized sampling methods allow efficient coverage of the complete design space, resulting in faster convergence and hence a reduced number of required simulations. In this study, a quasi-random sampling approach based on Sobol sequences is applied to select representative events for the determination of the lifetime damage. This is calculated applying Monte Carlo integration, using subsets of a resulting total of 16 200 coupled time–domain simulations performed with the simulation code FAST. The considered system is the Danmarks Tekniske Universitet (DTU) 10 MW reference turbine installed on the LIFES50+ OO-Star Wind Floater Semi 10 MW floating platform. Statistical properties of the considered environmental parameters (i.e., wind speed, wave height and wave period) are determined based on the measurement data from the Gulf of Maine, USA. Convergence analyses show that it is sufficient to perform around 200 simulations in order to reach less than 10 % uncertainty of lifetime fatigue damage-equivalent loading. Complementary in-depth investigation is performed, focusing on the load sensitivity and the impact of outliers (i.e., values far away from the mean). Recommendations for the implementation of the proposed methodology in the design process are also provided.

Thermal-aware Output Polarity Selection Based on And-Inverter Graph Manipulation

2019 ◽  
Vol 12 (1) ◽  
pp. 30-39 ◽  
Author(s):  
Apangshu Das ◽  
Sambhu Nath Pradhan
Keyword(s):  
Integrated Circuits ◽  
Power Density ◽  
Logic Synthesis ◽  
Programmable Logic Arrays ◽  
Power Switching ◽  
Nsga Ii ◽  
Multi Level ◽  
Search Approach ◽  
Efficient Power ◽  
The Impact

Background: Output polarity of the sub-function is generally considered to reduce the area and power of a circuit at the two-level realization. Along with area and power, the power-density is also one of the significant parameter which needs to be consider, because power-density directly converges to circuit temperature. More than 50% of the modern day integrated circuits are damaged due to excessive overheating. Methods: This work demonstrates the impact of efficient power density based logic synthesis (in the form of suitable polarity selection of sub-function of Programmable Logic Arrays (PLAs) for its multilevel realization) for the reduction of temperature. Two-level PLA optimization using output polarity selection is considered first and compared with other existing techniques and then And-Invert Graphs (AIG) based multi-level realization has been considered to overcome the redundant solution generated in two-level synthesis. AIG nodes and associated power dissipation can be reduced by rewriting, refactoring and balancing technique. Reduction of nodes leads to the reduction of the area but on the contrary increases power and power density of the circuit. A meta-heuristic search approach i.e., Nondominated Sorting Genetic Algorithm-II (NSGA-II) is proposed to select the suitable output polarity of PLA sub-functions for its optimal realization. Results: Best power density based solution saves up to 8.29% power density compared to ‘espresso – dopo’ based solutions. Around 9.57% saving in area and 9.67% saving in power (switching activity) are obtained with respect to ‘espresso’ based solution using NSGA-II. Conclusion: Suitable output polarity realized circuit is converted into multi-level AIG structure and synthesized to overcome the redundant solution at the two-level circuit. It is observed that with the increase in power density, the temperature of a particular circuit is also increases.

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