QCD event generators with next-to-leading order matrix-elements and   parton showers
  A new method to construct event-generators based on next-to-leading order QCD matrix-elements and leading-logarithmic parton showers is proposed. Matrix elements of loop diagram as well as those of a tree level can be generated using an automatic system. A soft/collinear singularity is treated using a leading-log subtraction method. Higher order re-summation of the soft/collinear correction by the parton shower method is combined with the NLO matrix-element without any double-counting in this method.   An example of the event generator for Drell-Yan process is given for demonstrating a validity of this method. 
Y. Kurihara, J. Fujimoto, T. Ishikawa, K. Kato, S. Kawabata, T.   Munehisa, H. Tanaka