Welcome to the 12th Annual International conference on Computational Science, to be held in Omaha, USA. This year’s conference will take place in Omaha, the heart of USA, at the Embassy suites – Downtown/Old Market. ICCS 2012 is organized by the University of Nebraska at Omaha, Universiteit van Amsterdam, the University of Tennessee, Nanyang Technological University, and Chinese Academy of Sciences Research Center on Fictitious Economy and Data Science. The International Conference on Computational Science aims to bring together annually researchers and scientists from mathematics and computer science as basic computing disciplines, researchers from various application areas who are pioneering advanced application of computational methods to sciences such as physics, chemistry, life sciences, and engineering, arts and humanitarian fields, along with software developers and vendors, to discuss problems and solutions in the area, to identify new issues, and to shape future directions for research, as well as to help industrial users apply various advanced computational techniques. ICCS 2012 will be the twelfth in this series of highly successful conferences. For details of the previous eleven very successful meetings see: http://www.iccs-meeting.org/iccs2012/previous-iccs.html The theme for ICCS 2012 is "Empowering Science through Computing", to mark the ever-increasing importance of and progress in computational science theory and practice. The conference will be a unique event focusing on recent developments in methods and modeling of complex systems for diverse areas of science, scalable scientific algorithms, advanced software tools, computational grids, advanced numerical methods, and novel application areas where the above novel models, algorithms and tools can be efficiently applied such as physical systems, computational and systems biology, environmental systems, finance, and others. For this great event, we have invited the following world leading keynote speakers to give their current and future vision of Computational Science: Dirk Helbing, ETH Zurich, Switzerland Frederica Darema, Air Force Office of Scientific Research, USA Michael L. Norman, San Diego Supercomputer Center, USA Philip S. Yu, University of Illinois at Chicago, USA Nin Zhong, Maebashi Institute of Technology, Japan Besides our excellent keynote speakers, out of the submitted papers to main track and workshops, we selected 235 high-quality papers for presentation at the conference and publication in the proceedings, published by Elsevier in their Procedia Computer Science series. These papers are collated into a single main track and nineteen workshops. The accepted papers are contributed by scholars and practitioners from many different countries across the globe. In addition to the keynote talks and presentations of