**Section 1**

**Advances in Grid Computing - Workflow** 

Dang Minh Quan1, Joern Altmann2 and Laurence T. Yang<sup>3</sup> <sup>1</sup>*Center for REsearch And Telecommunication Experimentation for*

**w-TG: A Combined Algorithm to Optimize** 

*Engineering, College of Engineering, Seoul National University* <sup>3</sup>*Department of Computer Science, St. Francis Xavier University*

**the Runtime of the Grid-Based** 

**Workflow Within an SLA Context** 

<sup>2</sup>*Technology Management, Economics, and Policy Program, Department of Industrial*

In the Grid Computing environment, many users need the results of their calculations within a specific period of time. Examples of those users are weather forecasters running weather forecasting workflows, and automobile producers running dynamic fluid simulation workflow Lovas et al. (2004). Those users are willing to pay for getting their work completed on time. However, this requirement must be agreed on by both, the users and the Grid provider, before the application is executed. This agreement is contained in the Service Level Agreement (SLA) Sahai et al. (2003). In general, SLAs are defined as an explicit statement of expectations and obligations in a business relationship between service providers and customers. SLAs specify the a-priori negotiated resource requirements, the quality of service (QoS), and costs. The application of such an SLA represents a legally binding contract. This is

However, letting Grid-based workflows' owners work directly with resource providers has

• The user has to have a sophisticated resource discovery and mapping tools in order to find

• The user has to manage the workflow, ranging from monitoring the running process to

To free users from this kind of work, it is necessary to introduce a broker to handle the workflow execution for the user. We proposed a business model Quan & J. Altmann (2007) for the system as depicted in Figure 1, in which, the SLA workflow broker represents the user as specified in the SLA with the user. This controls the workflow execution. This includes

a mandatory prerequisite for the Next Generation Grids.

**1. Introduction**

two main disadvantages:

handling error events.

the appropriate resource providers.

*NETworked Communities*

<sup>1</sup>*Italy*

**1**

<sup>2</sup>*South Korea* <sup>3</sup>*Canada*
