\documentclass[12pt,a4paper]{article} \title{Harnessing Wasted Computing Power for Scientific Computing} \author{S\'andor Guba, M\'at\'e \H{O}ry and Imre Szeber\'enyi\\ Budapest University of Technology and Economics, %\\ %Magyar Tud\'osok k\"or\'utja 2, H-1117 Budapest, Hungary} \date{\empty} \begin{document} \maketitle Nowadays more and more general purpose workstations installed in a student laboratory have built in multi-core CPU and graphics card providing significant computing power. In most cases the utilization of these resources is low, and limited to lecture hours. The concept of utility computing plays an important role in nowadays technological development. As part of utility computing, cloud computing offers greater flexibility and responsiveness to ICT users at lower cost. In this paper, we introduce a cloud management system which enables the simultaneous use of both dedicated resources and opportunistic environment. All the free workstations (powered or not) are automatically added to a resource pool, and can be used like ordinary cloud resources. Researchers can launch various virtualized software appliances. Our solution leverages the advantages of HTCondor and OpenNebula systems. Modern graphics processing units (GPUs) with many-core architectures have emerged as general-purpose parallel computing platforms that can dramatically accelerate scientific applications used for various simulations. Our business model harnesses computing power of GPUs as well, using the needed amount of unused machines. This makes the infrastructure flexible and power efficient. Our pilot infrastructure consist of a high performance cluster and 28 workstations with dual-core CPUs and dedicated graphics cards. Altogether we can use 10,752 CUDA cores through the network. \end{document}