Scientific workflows and clouds

Besides public data repositories, scientific collaborations maintain community-wide data resources. For example, in gravitational-wave physics, the Laser Interferometer Gravitational-Wave Observatory [3] maintains geographically distributed repositories holding time-series data collected by the instruments and their associated metadata. Along with the large increase in online data, the need to process these data is growing. In addition to traditional high performance computing (HPC) cen-ters, a nation-wide cyberinfrastructure—a computational environ-ment, usually distributed, that hosts a number of heterogeneous resources; cyberinfrastructure could refer to both grids and clouds or a mix of the two—is being provided to the scientific community, including the Open Science Grid (OSG) [36] and the TeraGrid [47]. These infrastructures, also known as grids [13], allow access to high-performance resources over wide area networks. For example, th