Introducing risk management into the grid

Service Level Agreements (SLAs) are explicit statements about all expectations and obligations in the business partnership between customers and providers. They have been introduced in Grid computing to overcome the best effort approach, making the Grid more interesting for commercial applications. However, decisions on negotiation and system management still rely on static approaches, not reflecting the risk linked with decisions. The EC-funded project "AssessGrid" aims at introducing risk assessment and management as a novel decision paradigm into Grid computing. This paper gives a general motivation for risk management and presents the envisaged architecture of a "risk-aware" Grid middleware and Grid fabric, highlighting its functionality by means of three showcase scenarios

Mining Repair Actions for Guiding Automated Program Fixing

Automated program fixing consists of generating source code in order to fix bugs in an automated manner. Our intuition is that automated program fixing can imitate human-based program fixing. Hence, we present a method to mine repair actions from software repositories. A repair action is a small semantic modification on code such as adding a method call. We then decorate repair actions with a probability distribution also learnt from software repositories. Our probabilistic repair models enable us to mathematically reason on the automated software repair process. By applying our method on 14 repositories of Java software and 89993 versioning transactions, we show that our probabilistic repair actions are able to guide the automated fixing process in the repair space, with a probabilistic focus on likely repair shapes first

Earned schedule formulation using nonlinear cost estimates at completion

This work contributes to improving available methodologies for duration and cost estimates of ongoing projects with nonlinear cost profiles. It is demonstrated that accurate time estimates can be made when a generalized mathematical formulation of the Earned Schedule and the point estimate methodology are used. It also highlights the advantages of using these duration estimate methodologies to provide more accurate nonlinear schedule-based cost estimates at completion. This is shown via application and comparison of the proposed methodologies to datasets of eight real case projects from the construction industry. In particular, the defined methodologies tend to perform better, on average, than traditional index-based formulae, especially in the early stages of project development when the practical benefits are the greatest for project teams to take their corrective actions