Xiao Liu PhD Thesis.pdf - Faculty of Information and Communication ...

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violations. Furthermore, the monetary cost for reserving and using a new resource is much higher in comparison to the computation cost required for ACOWR. As for the other representative strategies such as Stop and Restart [28], Processor Swapping [28] and Workflow Restructure [83], they are either similar to Add or requiring human interventions. Therefore, given the basic requirements of automation and cost-effectiveness for handling recoverable temporal violations, all these expensive strategies are not suitable candidates. Detailed results have been included in our online document (see footnote 9). 8.7 Summary In this chapter, we have presented an overview of the temporal violation handling strategies for temporal violations in scientific cloud workflow systems. Given the definitions of statistically recoverable and non-recoverable temporal violations, the temporal violation handling strategies are also classified into light-weight and heavy-weight temporal violation handling strategies. Specifically, a novel lightweight two-stage local workflow rescheduling strategy is presented to handle recoverable temporal violations. The abstract strategy has been implemented with both GA and ACO metaheuristic algorithms. Based on four basic measurements, the experimental results have shown that the two-stage local workflow rescheduling strategy is capable of compensating large time deficits with small CPU time. In the future, the existing temporal violation handling strategies for statistically non-recoverable temporal violations will be further investigated and adapted for cost-effective application in scientific cloud workflow systems. 160
Chapter 9 Conclusions and Future Work The technical details for our novel probabilistic temporal framework have all been addressed in the previous chapters. In this chapter, we summarise the whole thesis. This chapter is organised as follows. Section 9.1 presents an overall cost analysis for the temporal framework. Section 9.2 summarises the contents of the whole thesis. Section 9.3 outlines the main contributions of this thesis. Finally, Section 9.4 points out the future work. 9.1 Overall Cost Analysis for Temporal Framework This thesis proposes a framework which can cost effectively deliver high temporal QoS (quality of service) in scientific cloud workflow systems. As demonstrated in Section 8.6, based on our temporal framework, the average global violation rate of simulated scientific cloud workflows is 0.167%, and the average local violation rate is 0.13%. Therefore, we can claim that high temporal QoS in scientific cloud workflow systems can be achieved with the support of our temporal framework. Based on the achievement of high temporal QoS, we further analyse whether our temporal framework achieves cost effectiveness. The overall running cost of the temporal framework consists of the time overheads and monetary cost for each component. Specifically, our temporal framework consists of three major components, viz. Component I: temporal constraint setting, Component II: temporal consistency monitoring, and Component III: temporal violation handling. For Component I (temporal constraint setting), with the support of an accurate 161
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A Novel Probabilistic Temporal Fram
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Declaration This thesis contains no
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Abstract Cloud computing is a lates
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Component 2, the state of scientifi
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http://dx.doi.org/10.1016/j.jpdc.20
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17. X. Liu, J. Chen, and Y. Yang, A
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4.2 RELATED WORK AND PROBLEM ANALYS
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STRATEGY ..........................
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FIGURE 7.4 EXPERIMENTAL RESULTS (NO
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Chapter 1 Introduction This thesis
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Clearly, if the execution time of t
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to seek all the candidates. Further
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e unnecessary. Hence, an effective
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temporal violations, viz. recoverab
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In Chapter 2, we introduce the rela
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a two-stage searching process with
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QoS requirements. Generally speakin
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handling strategies employed in a s
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activity points to conduct temporal
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compensation, is believed as a suit
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successful completion. Specifically
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Chapter 4 and Chapter 5 respectivel
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etween time deficit compensation an
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service user’s requirements and t
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conducted for three times, i.e. sta
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PTDA+ACOWR as an example to introdu
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currently running. It is built on t
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workflow instance to determine whet
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framework for cost-effective delive
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pattern based forecasting strategy.
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4.2 Related Work and Problem Analys
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4.2.2 Problem Analysis In cloud wor
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significantly deteriorate the overa
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activity durations: characteristics
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specified with different means and
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Table 4.1 Notations Used in K-MaxSD
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1) Duration series building As ment
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Table 4.5 Algorithm 4: Pattern Matc
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to search for those activities whic
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cycle. Here, we also trace back the
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ecognition. Sliding Window ranks in
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predicted value will be the one pre
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segmentation algorithm is capable o
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distributed soft real-time system,
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Table 5.1 Overview on the Support o
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2 2 can be denoted as N ( µ , σ )
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mean iteration times or with some p
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Figure 5.4 Choice Building Block No
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activities may be omitted for the e
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5.3.1 Calculating Weighted Joint Di
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constraints until the constraint is
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Therefore, it can be expressed as n
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Table 5.3 Specification of the Work
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and the constraint for activity X 1
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ease of discussion and to avoid the
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Unfortunately, conventional discret
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The probability consistency range w
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6.2.3 Temporal Checkpoint Selection
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100 times each. All the activity du
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normal distribution and correlated
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Figure 6.3 Checkpoint Selection wit
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work and problem analysis. Section
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expected time redundancy of subsequ
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Page 137 and 138: Figure 7.5 Cost Reduction Rate vs.
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Page 163 and 164: D: Definition for Fitness Value Fit
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Page 189 and 190: Bibliography [1] W. M. P. van der A
Page 191 and 192: Systems", ACM Trans. on Software En
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Page 195 and 196: Elsevier, vol. 84, no. 3, pp. 354-3
Page 197 and 198: Distributed Computing Systems", Jou
Page 199 and 200: Appendix: Notation Index Symbols α
Page 201 and 202: PTR ( U ( SW ), ( a p + , a p + 1 m
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