The Experts below are selected from a list of 25563 Experts worldwide ranked by ideXlab platform
Yun Yang - One of the best experts on this subject based on the ideXlab platform.
-
Adaptive Selection of Necessary and Sufficient Checkpoints for Dynamic Verification of Temporal Constraints in Grid Workflow Systems
2015Co-Authors: Jinjun Chen, Yun YangAbstract:In grid workflow systems, a checkpoint selection strategy is responsible for selecting checkpoints for conducting Temporal Verification at the runtime execution stage. Existing representative check-point selection strategies often select some unnecessary checkpoints and omit some necessary ones because they cannot adapt to the dynamics and uncertainty of runtime activity completion duration. In this article, based on the dynamics and uncertainty of runtime activity completion duration, we develop a novel checkpoint selection strategy that can adaptively select not only necessary, but also sufficient checkpoints. Specifically, we introduce a new concept of minimum time redundancy as a key reference parameter for checkpoint selection. An important feature of minimum time redun-dancy is that it can adapt to the dynamics and uncertainty of runtime activity completion duration. We develop a method on how to achieve minimum time redundancy dynamically along grid work-flow execution and investigate its relationships with Temporal consistency. Based on the method and the relationships, we present our strategy and rigorously prove its necessity and sufficiency. The simulation evaluation further demonstrates experimentally such necessity and sufficiency an
-
An Activity Completion Duration based Checkpoint Selection Strategy for Dynamic Verification of Fixed-time Constraints
2013Co-Authors: Jinjun Chen, Yun YangAbstract:In grid workflow systems, to verify Temporal constraints efficiently at run-time execution stage, some checkpoints are often selected so that we only need to conduct Temporal Verification at such checkpoints rather than at all activity points. However, existing typical checkpoint selection strategies often ignore some necessary checkpoints and select some unnecessary ones. This would eventually impact overall Temporal Verification effectiveness and efficiency. To improve such status, in this paper, we develop a new checkpoint selection strategy. Specifically, we first investigate the relationships between activity completion duration and the consistency of Temporal constraints. Then, based on those relationships we present our new checkpoint selection strategy. Our new strategy can avoid the omission of necessary checkpoints and the selection of excess unnecessary checkpoints. Consequently, it can achieve better Temporal Verification effectiveness and efficiency than the existing typical checkpoint selection strategies. The final comparison and quantitative evaluation further demonstrate this result. Key words: grid workflows, Temporal constraints, checkpoint selection, Temporal Verification effectiveness, Temporal Verification efficienc
-
Temporal Violation Handling
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Xiao Liu, Yun Yang, Jinjun ChenAbstract:Temporal violation handling is the key of the last component in our Temporal framework for scientific cloud workflow systems. Clearly, whether a detected Temporal violation can be recovered or not mainly depends on the performance of Temporal violation handling strategies employed in the system. Meanwhile, since the time overheads and monetary cost for Temporal violation handling strategies are usually much more expensive than that of its precedent steps such as checkpoint selection and Temporal Verification, cost-effective Temporal violation handling strategies are required to be employed or designed to reduce the overall cost of the Temporal framework.
-
Temporal Violation Handling Point Selection
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Xiao Liu, Yun Yang, Jinjun ChenAbstract:In scientific cloud workflow systems, Temporal violation handling points are those workflow activity points where Temporal violation handling strategies are triggered to tackle detected Temporal violations. The existing work on Temporal Verification adopts the philosophy of Temporal violation handling required whenever a Temporal violation is detected. Therefore, a checkpoint is regarded the same as a Temporal violation handling point. However, the probability of self-recovery which utilises the time redundancy of subsequent workflow activities to automatically compensate for the time deficit is ignored and hence would impose a high-Temporal violation handling cost. To address such a problem, this book presents a novel adaptive Temporal violation handling point selection strategy where the probability of self-recovery is effectively utilised in Temporal violation handling point selection to avoid unnecessary handling for Temporal violations. This chapter is organised as follows. Section 8.1 presents the specifically related work and problem analysis. Section 8.2 presents our novel adaptive Temporal violation handling point selection strategy. Section 8.3 demonstrates the evaluation results.
-
Forecasting Scientific Cloud Workflow Activity Duration Intervals
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Yun Yang, Jinjun ChenAbstract:As discussed in Chapter 2, workflow activity duration is one of the basic elements in the Temporal consistency model, and thus its accuracy is critical for the effectiveness of Temporal Verification and all the other related components such as Temporal checkpoint selection and Temporal violation handling. Therefore, an accurate forecasting strategy is required to predict cloud workflow activity durations. However, it is not a trivial issue due to the dynamic nature of cloud computing environments. In this chapter, we present a statistical time-series-based forecasting strategy for scientific cloud workflow activity duration intervals. The comparison results demonstrate that our strategy has better performance than the other existing representative strategies. This chapter is organised as follows. Section 5.1 gives a general introduction about cloud workflow activity durations. Section 5.2 presents the specifically related work and problem analysis. Section 5.3 presents the novel statistical time-series-pattern-based forecasting strategy. Section 5.4 demonstrates the experimental results.
Jinjun Chen - One of the best experts on this subject based on the ideXlab platform.
-
Adaptive Selection of Necessary and Sufficient Checkpoints for Dynamic Verification of Temporal Constraints in Grid Workflow Systems
2015Co-Authors: Jinjun Chen, Yun YangAbstract:In grid workflow systems, a checkpoint selection strategy is responsible for selecting checkpoints for conducting Temporal Verification at the runtime execution stage. Existing representative check-point selection strategies often select some unnecessary checkpoints and omit some necessary ones because they cannot adapt to the dynamics and uncertainty of runtime activity completion duration. In this article, based on the dynamics and uncertainty of runtime activity completion duration, we develop a novel checkpoint selection strategy that can adaptively select not only necessary, but also sufficient checkpoints. Specifically, we introduce a new concept of minimum time redundancy as a key reference parameter for checkpoint selection. An important feature of minimum time redun-dancy is that it can adapt to the dynamics and uncertainty of runtime activity completion duration. We develop a method on how to achieve minimum time redundancy dynamically along grid work-flow execution and investigate its relationships with Temporal consistency. Based on the method and the relationships, we present our strategy and rigorously prove its necessity and sufficiency. The simulation evaluation further demonstrates experimentally such necessity and sufficiency an
-
An Activity Completion Duration based Checkpoint Selection Strategy for Dynamic Verification of Fixed-time Constraints
2013Co-Authors: Jinjun Chen, Yun YangAbstract:In grid workflow systems, to verify Temporal constraints efficiently at run-time execution stage, some checkpoints are often selected so that we only need to conduct Temporal Verification at such checkpoints rather than at all activity points. However, existing typical checkpoint selection strategies often ignore some necessary checkpoints and select some unnecessary ones. This would eventually impact overall Temporal Verification effectiveness and efficiency. To improve such status, in this paper, we develop a new checkpoint selection strategy. Specifically, we first investigate the relationships between activity completion duration and the consistency of Temporal constraints. Then, based on those relationships we present our new checkpoint selection strategy. Our new strategy can avoid the omission of necessary checkpoints and the selection of excess unnecessary checkpoints. Consequently, it can achieve better Temporal Verification effectiveness and efficiency than the existing typical checkpoint selection strategies. The final comparison and quantitative evaluation further demonstrate this result. Key words: grid workflows, Temporal constraints, checkpoint selection, Temporal Verification effectiveness, Temporal Verification efficienc
-
Temporal Violation Handling
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Xiao Liu, Yun Yang, Jinjun ChenAbstract:Temporal violation handling is the key of the last component in our Temporal framework for scientific cloud workflow systems. Clearly, whether a detected Temporal violation can be recovered or not mainly depends on the performance of Temporal violation handling strategies employed in the system. Meanwhile, since the time overheads and monetary cost for Temporal violation handling strategies are usually much more expensive than that of its precedent steps such as checkpoint selection and Temporal Verification, cost-effective Temporal violation handling strategies are required to be employed or designed to reduce the overall cost of the Temporal framework.
-
Temporal Violation Handling Point Selection
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Xiao Liu, Yun Yang, Jinjun ChenAbstract:In scientific cloud workflow systems, Temporal violation handling points are those workflow activity points where Temporal violation handling strategies are triggered to tackle detected Temporal violations. The existing work on Temporal Verification adopts the philosophy of Temporal violation handling required whenever a Temporal violation is detected. Therefore, a checkpoint is regarded the same as a Temporal violation handling point. However, the probability of self-recovery which utilises the time redundancy of subsequent workflow activities to automatically compensate for the time deficit is ignored and hence would impose a high-Temporal violation handling cost. To address such a problem, this book presents a novel adaptive Temporal violation handling point selection strategy where the probability of self-recovery is effectively utilised in Temporal violation handling point selection to avoid unnecessary handling for Temporal violations. This chapter is organised as follows. Section 8.1 presents the specifically related work and problem analysis. Section 8.2 presents our novel adaptive Temporal violation handling point selection strategy. Section 8.3 demonstrates the evaluation results.
-
Forecasting Scientific Cloud Workflow Activity Duration Intervals
Temporal QOS Management in Scientific Cloud Workflow Systems, 2012Co-Authors: Yun Yang, Jinjun ChenAbstract:As discussed in Chapter 2, workflow activity duration is one of the basic elements in the Temporal consistency model, and thus its accuracy is critical for the effectiveness of Temporal Verification and all the other related components such as Temporal checkpoint selection and Temporal violation handling. Therefore, an accurate forecasting strategy is required to predict cloud workflow activity durations. However, it is not a trivial issue due to the dynamic nature of cloud computing environments. In this chapter, we present a statistical time-series-based forecasting strategy for scientific cloud workflow activity duration intervals. The comparison results demonstrate that our strategy has better performance than the other existing representative strategies. This chapter is organised as follows. Section 5.1 gives a general introduction about cloud workflow activity durations. Section 5.2 presents the specifically related work and problem analysis. Section 5.3 presents the novel statistical time-series-pattern-based forecasting strategy. Section 5.4 demonstrates the experimental results.
Haoyu Luo - One of the best experts on this subject based on the ideXlab platform.
-
adaptive Temporal Verification and violation handling for time constrained business cloud workflows
International Conference on Service Oriented Computing, 2018Co-Authors: Haoyu Luo, Jin Liu, Bo HanAbstract:To achieve on-time completion of time-constrained business cloud workflows, a large number of parallel cloud workflow instances need to be constantly monitored so that Temporal violations (namely intermediate runtime delays) can be detected and handled timely. Over the last few years, many strategies have been proposed but they are not adaptive enough to capture the dynamic behaviors of business cloud workflows. In this paper, we introduce the idea of “adaptiveness” into our strategy design. Specifically, we first present an adaptive Temporal checkpoint selection strategy where the time intervals between checkpoints are adaptively determined at runtime, and then propose a matching Temporal violation handling strategy which can determine the required lifecycle of cloud services. The evaluation results demonstrate that our adaptive strategy can achieve both higher efficiency and better cost effectiveness compared with conventional strategies.
-
A sufficient and necessary Temporal violation handling point selection strategy in cloud workflow
Future Generation Computer Systems, 2018Co-Authors: Yeguo Wang, Futian Wang, Haoyu Luo, Ying XieAbstract:Abstract To deliver high QoS (quality of service) for business process participants, workflow Temporal Verification is conducted to provide satisfactory on-time completion rate of business process in the cloud. Temporal violation handling is the last task in a typical workflow Temporal Verification framework to deal with detected time delays. However, there are very few existing studies regarding Temporal violation handling for cloud business workflows. In this paper, queuing theory is first employed to simulate time features of parallel workflow instances. Then, propagation effect based Temporal consistency model for business workflows and Temporal consistency model for workflow activities in the same queuing system are presented respectively. Finally, a promising Temporal violation handling point selection strategy for cloud business workflows is proposed and proved to satisfy the property of sufficiency and necessity. Compared with other representative strategies, experimental results show that our novel handling point selection strategy can reduce the monitoring and handling cost while maintaining the target on-time completion rate agreed between users and service providers.
Futian Wang - One of the best experts on this subject based on the ideXlab platform.
-
A sufficient and necessary Temporal violation handling point selection strategy in cloud workflow
Future Generation Computer Systems, 2018Co-Authors: Yeguo Wang, Futian Wang, Haoyu Luo, Ying XieAbstract:Abstract To deliver high QoS (quality of service) for business process participants, workflow Temporal Verification is conducted to provide satisfactory on-time completion rate of business process in the cloud. Temporal violation handling is the last task in a typical workflow Temporal Verification framework to deal with detected time delays. However, there are very few existing studies regarding Temporal violation handling for cloud business workflows. In this paper, queuing theory is first employed to simulate time features of parallel workflow instances. Then, propagation effect based Temporal consistency model for business workflows and Temporal consistency model for workflow activities in the same queuing system are presented respectively. Finally, a promising Temporal violation handling point selection strategy for cloud business workflows is proposed and proved to satisfy the property of sufficiency and necessity. Compared with other representative strategies, experimental results show that our novel handling point selection strategy can reduce the monitoring and handling cost while maintaining the target on-time completion rate agreed between users and service providers.
-
Necessary and sufficient checkpoint selection for Temporal Verification of high-confidence cloud workflow systems
Science China Information Sciences, 2015Co-Authors: Futian Wang, Xiao LiuAbstract:On-time completion is an important Temporal QoS (Quality of Service) dimension and one of the fundamental requirements for high-confidence workflow systems. In recent years, a workflow Temporal Verification framework, which generally consists of Temporal constraint setting, Temporal checkpoint selection, Temporal Verification, and Temporal violation handling, has been the major approach for the high Temporal QoS assurance of workflow systems. Among them, effective Temporal checkpoint selection, which aims to timely detect intermediate Temporal violations along workflow execution plays a critical role. Therefore, Temporal checkpoint selection has been a major topic and has attracted significant efforts. In this paper, we will present an overview of work-flow Temporal checkpoint selection for Temporal Verification. Specifically, we will first introduce the throughput based and response-time based Temporal consistency models for business and scientific cloud workflow systems, respectively. Then the corresponding benchmarking checkpoint selection strategies that satisfy the property of “necessity and sufficiency” are presented. We also provide experimental results to demonstrate the effectiveness of our checkpoint selection strategies, and finally points out some possible future issues in this research area.
Bo Han - One of the best experts on this subject based on the ideXlab platform.
-
adaptive Temporal Verification and violation handling for time constrained business cloud workflows
International Conference on Service Oriented Computing, 2018Co-Authors: Haoyu Luo, Jin Liu, Bo HanAbstract:To achieve on-time completion of time-constrained business cloud workflows, a large number of parallel cloud workflow instances need to be constantly monitored so that Temporal violations (namely intermediate runtime delays) can be detected and handled timely. Over the last few years, many strategies have been proposed but they are not adaptive enough to capture the dynamic behaviors of business cloud workflows. In this paper, we introduce the idea of “adaptiveness” into our strategy design. Specifically, we first present an adaptive Temporal checkpoint selection strategy where the time intervals between checkpoints are adaptively determined at runtime, and then propose a matching Temporal violation handling strategy which can determine the required lifecycle of cloud services. The evaluation results demonstrate that our adaptive strategy can achieve both higher efficiency and better cost effectiveness compared with conventional strategies.
