One-loop matrix elements of effective superstring interactions: α′-expanding loop integrands

In the low-energy effective action of string theories, non-abelian gauge interactions and supergravity are augmented by infinite towers of higher-mass-dimension operators. We propose a new method to construct one-loop matrix elements with insertions of operators D2kFn and D2kRn in the tree-level effective action of type-I and type-II superstrings. Inspired by ambitwistor string theories, our method is based on forward limits of moduli-space integrals using string tree-level amplitudes with two extra points, expanded in powers of the inverse string tension α′. Similar to one-loop ambitwistor computations, intermediate steps feature non-standard linearized Feynman propagators which eventually recombine to conventional quadratic propagators. With linearized propagators the loop integrand of the matrix elements obey one-loop versions of the monodromy and KLT relations. We express a variety of four- and five-point examples in terms of quadratic propagators and formulate a criterion on the underlying genus-one correlation functions that should make this recombination possible at all orders in α′. The ultraviolet divergences of the one-loop matrix elements are crosschecked against the non-separating degeneration of genus-one integrals in string amplitudes. Conversely, our results can be used as a constructive method to determine degenerations of elliptic multiple zeta values and modular graph forms at arbitrary weight.

Accelerating LHC phenomenology with analytic one-loop amplitudes

The evaluation of one-loop matrix elements is one of the main bottlenecks in precision calculations for the high-luminosity phase of the Large Hadron Collider. To alleviate this problem, a new C++ interface to the "Image missing" parton-level Monte Carlo is introduced, giving access to an extensive library of analytic results for one-loop amplitudes. Timing comparisons are presented for a large set of Standard Model processes. These are relevant for high-statistics event simulation in the context of experimental analyses and precision fixed-order computations.

Gas distribution network topology problem

Problem of gas flow in looped network is nonlinear problem and these kind of problemshave to be solved using some kind of iterative procedure. For the pipeline network, two topologymatrices can be written; i.e. loop matrix and node matrix. The node matrix is related to therst Kirchho's law while the loop matrix is related to second Kirchho's law. Here will beshown ecient method in which both matrices, i.e. the node and the loop matrix are unitedin one coherent procedure for solution of looped gas pipeline problem.

Valve-Shut off Scheme and Affected Zone Analysis of Multi-Sources Looped-Pipe Network Based on ARCGIS

Based on ArcGIS,Multi-heat sources and multi-loops complex heating network is Modeled and simulated ,and a functional method is put forward, by using Geodatabase data model,it can creat relating matrix and basic loop matrix of heat network quickly,and calculate Hydraulic Regime of heating Network with the Basic Circuit.When pipe-bursting accident occur in heating Network,along with changes in the logical network model.also the entire calculation model is changed.This method is applied to the Study of Valve-shut off scheme after tube-burst accident ,the heating Influence of the accident can be quantitative analyzed , also the degree of influence is compared when tube-burst accident happen at different place.

Distribution System Restoration Based on Hybrid Particle Swarm

By the heuristic algorithm and particle swarm optimization algorithm combining hybrid particle swarm algorithm proposed combination of heuristic search and stochastic optimization,stochastic optimization process using a spanning tree and the loop matrix operations combined to ensure the system topology constraints to improve the efficiency of solution. The analysis shows that the proposed method calculation speed,easy to converge to the global optimal solution. It can effectively solve the problem of distribution network fault recovery.

Optimizing the Operation of Distributed Generation Using Genetic Algorithms

By the heuristic algorithm and particle swarm optimization algorithm combining hybrid particle swarm algorithm proposed combination of heuristic search and stochastic optimization,stochastic optimization process using a spanning tree and the loop matrix operations combined to ensure the system topology constraints to improve the efficiency of solution. The analysis shows that the proposed method calculation speed,easy to converge to the global optimal solution. Development of distributed generation units, along with concerns raised over the security of supply has prompted many customers to consider the installation of their own local capacity for generating electricity (and heat). This paper proposes a methodology for optimizing the operation of a portfolio of distributed units, based on profit maximization using genetic algorithms. The method is tested on a set of distributed units, demonstrating the ability to find good solutions in an acceptable time period.