Summary about workflow

1. Summary about workflow 张凌志 2011.3.18

2. Workflow is the automation of the operations based on the computer. • In order to achieve the goal, all the information and the small tasks are flowing in the network obeyed by the certain rules.

3. Firstly, the workflow management system will divide the submitted task into several small tasks that can be finished by a certain resource. • Secondly, according to the QOS ordered by the users, we will choose the resources and make the routes.

4. We can divide the second part into three parts. • 1. How to choose the resource? • 2. How to define the order obeyed by the tasks in the network? • 3. How to routes them?

5. The first question • There are many methods for that. • They can be divided by the measurement. • 1. time • 2. cost • 3. multiple degrees

6. time • The common ways measured with time are showed as follows: • 1. DBL (deadline bottom level) • 2. MCP (minimum critical path) • 3. DTL (deadline top level) • 4. PSO (particle swarm optimization) • The advanced methods of the first one take the floating value into account and assign it to different tasks.

7. cost • The cost can be divided into two parts, the cost of the resource and the cost of the bandwidth. • As we known, different resources have different QOS, so the cost of the resources are also different. • If time areas we assigned to the task are different, the bandwidth we chosen must be different, then the cost the provider has to pay is different.

8. multiple degrees • In “multiple QOS-based best efficiency workflow scheduling”, the author model several measurements together.

9. The second question • In “scheduling algorithm for workflow-based applications in optical grid (JLT)”, he assigns the tasks into different levels and uses the SCP (scheduled critical path) to determine the order. • The SCP is the path which takes more time than the others.

10. The third question • There are many methods in this part. Recently, I focus on the method using the fault probability. • Zhong defines the “failure probability” while Xia defines the “SLA( service level agreement) risk” in their paper. • But both of them assume that only one simultaneous link failure can occur on the network and ignore the failure occurred on the node.

11. Two simultaneous link failure • In “availability-constrained multipath protection in backbone networks with double-link failure (ICC)”, the author take two simultaneous link failure into account. • But it only can be used in the self-protecting multi-path environment.

13. SRG • In “capacity performance of dynamic provisioning in optical networks (JLT)”, the author puts forward the definition “SRG (shared risk groups)”. • This method can simulate the reality, but it can do nothing to the scheduling.

14. SRG

15. penalization • In order to improve the availability, we have to use different protections. If we take the utilization of the resource into account and use the link-sharing protection, then we may meet some risk. • In “survivable multipath routing using link penalization”, the author define link penalization to reduce the risk that link-sharing causes.

16. future • The thing I will focus on can be divided into two parts. • 1. whether we can control the number of the tasks. • 2. How to choose the resource by considering both the link-failure probability and the QOS of the resource

17. Thank you！