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Yuhong Yan - One of the best experts on this subject based on the ideXlab platform.
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Redundant Service removal in qos aware Service composition
International Conference on Web Services, 2012Co-Authors: Min Chen, Yuhong YanAbstract:QoS-aware Service composition is the generation of a business process to fulfill functional goals and optimize the QoS criteria at the same time. People may focus on the optimization of a single QoS criterion or a set of QoS criteria. We find that though many composition algorithms can get the optimal QoS values, the solutions obtained can possibly contain Redundant Services, the removal of which does not worsen the QoS value of the solution. In the literatures using Web Service Challenge (WSC) open data sets, the removable Services can be over 30% of the Services in the solutions. This common problem has been ignored so far. The fundamental reason is that execution cost is not one of the criteria to optimize. Even in the cases when execution costs are not explicitly given for each Service, we are still motivated to reduce the number of Services in the final solution by assuming each Service takes unit cost. In this paper, we study the redundancy removal problem to further optimize the QoS optimal solutions obtained by QoS-aware Service composition algorithms. We model the redundancy removal problem as an integer programming problem. Though solvable using a standard solver, we present an algorithm to solve the problem in this specific context and it proves to have better performance than a standard integer programming solver. We also present the results of our data experiments.
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ICWS - Redundant Service Removal in QoS-Aware Service Composition
2012 IEEE 19th International Conference on Web Services, 2012Co-Authors: Min Chen, Yuhong YanAbstract:QoS-aware Service composition is the generation of a business process to fulfill functional goals and optimize the QoS criteria at the same time. People may focus on the optimization of a single QoS criterion or a set of QoS criteria. We find that though many composition algorithms can get the optimal QoS values, the solutions obtained can possibly contain Redundant Services, the removal of which does not worsen the QoS value of the solution. In the literatures using Web Service Challenge (WSC) open data sets, the removable Services can be over 30% of the Services in the solutions. This common problem has been ignored so far. The fundamental reason is that execution cost is not one of the criteria to optimize. Even in the cases when execution costs are not explicitly given for each Service, we are still motivated to reduce the number of Services in the final solution by assuming each Service takes unit cost. In this paper, we study the redundancy removal problem to further optimize the QoS optimal solutions obtained by QoS-aware Service composition algorithms. We model the redundancy removal problem as an integer programming problem. Though solvable using a standard solver, we present an algorithm to solve the problem in this specific context and it proves to have better performance than a standard integer programming solver. We also present the results of our data experiments.
Min Chen - One of the best experts on this subject based on the ideXlab platform.
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QoS-aware Service Composition and Redundant Service Removal
2015Co-Authors: Min ChenAbstract:Automatic Service Composition (ASC) is the generation of a business process to fulfill business goals that cannot be fulfilled by individual Services. Planning algorithms are frequently used to solve this problem. In addition to satisfying functional goals, recent research is geared towards selecting the best Services to optimize the QoS of the business process results. It is a challenge to fulfill functional goals and achieve QoS optimization at the same time. In this thesis, we propose to combine a planning algorithm called GraphPlan, with a systematic search algorithm like Dijkstra's algorithm to achieve functional goals and QoS optimization at the same time. The GraphPlan algorithm has the advantages of easily modeling business logic, reusing the actions in one plan, and planning parallel actions in a plan. The planning graph generated by the GraphPlan algorithm is a compact representation of all execution paths, which makes it feasible to apply Dijkstra's principle. Two methods have been proposed to combine the Graphplan with Dijkstra's algorithm. In the first method, we extend Dijkstra's algorithm from working on a single source graph to working on the extended planning graph whose nodes have multiple sources. The advantage of this method is that it gets an optimal plan with the best QoS value for the single criteria of throughput or response time in polynomial time. However, this method does not provide a uniform graph structure (\ie an extended planning graph with single or multiple tag, to generate an optimal plan for all kinds of quality criteria). In the second method, we improve the idea of combining the Graphplan with Dijkstra's algorithm by providing a uniform graph structure to generate a QoS optimal solution for all kinds of quality criteria. A Layered Weighted Graph (LWG) is generated and provides a uniform structure for the easy use of Dijkstra's algorithm to find an optimal plan for all kinds of quality criteria. By using multi-objective shortest path algorithms, this method can be easily extended to solve QoS optimization on multiple QoS criterion for Service composition problem. In this thesis, we also study Redundant Service removal to further optimize QoS optimal solutions. The removal of Redundant Services does not worsen the QoS value of the optimal solution. Fewer numbers of Services indicates less execution costs to invoke these Services. A Redundant Service removal problem is modeled as an optimization problem such that the optimal solution without redundancy is found.
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Redundant Service removal in qos aware Service composition
International Conference on Web Services, 2012Co-Authors: Min Chen, Yuhong YanAbstract:QoS-aware Service composition is the generation of a business process to fulfill functional goals and optimize the QoS criteria at the same time. People may focus on the optimization of a single QoS criterion or a set of QoS criteria. We find that though many composition algorithms can get the optimal QoS values, the solutions obtained can possibly contain Redundant Services, the removal of which does not worsen the QoS value of the solution. In the literatures using Web Service Challenge (WSC) open data sets, the removable Services can be over 30% of the Services in the solutions. This common problem has been ignored so far. The fundamental reason is that execution cost is not one of the criteria to optimize. Even in the cases when execution costs are not explicitly given for each Service, we are still motivated to reduce the number of Services in the final solution by assuming each Service takes unit cost. In this paper, we study the redundancy removal problem to further optimize the QoS optimal solutions obtained by QoS-aware Service composition algorithms. We model the redundancy removal problem as an integer programming problem. Though solvable using a standard solver, we present an algorithm to solve the problem in this specific context and it proves to have better performance than a standard integer programming solver. We also present the results of our data experiments.
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ICWS - Redundant Service Removal in QoS-Aware Service Composition
2012 IEEE 19th International Conference on Web Services, 2012Co-Authors: Min Chen, Yuhong YanAbstract:QoS-aware Service composition is the generation of a business process to fulfill functional goals and optimize the QoS criteria at the same time. People may focus on the optimization of a single QoS criterion or a set of QoS criteria. We find that though many composition algorithms can get the optimal QoS values, the solutions obtained can possibly contain Redundant Services, the removal of which does not worsen the QoS value of the solution. In the literatures using Web Service Challenge (WSC) open data sets, the removable Services can be over 30% of the Services in the solutions. This common problem has been ignored so far. The fundamental reason is that execution cost is not one of the criteria to optimize. Even in the cases when execution costs are not explicitly given for each Service, we are still motivated to reduce the number of Services in the final solution by assuming each Service takes unit cost. In this paper, we study the redundancy removal problem to further optimize the QoS optimal solutions obtained by QoS-aware Service composition algorithms. We model the redundancy removal problem as an integer programming problem. Though solvable using a standard solver, we present an algorithm to solve the problem in this specific context and it proves to have better performance than a standard integer programming solver. We also present the results of our data experiments.
Stephen L. Scott - One of the best experts on this subject based on the ideXlab platform.
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Symmetric active/active metadata Service for high availability parallel file systems
Journal of Parallel and Distributed Computing, 2009Co-Authors: Christian Engelmann, Xin Chen, Stephen L. ScottAbstract:High availability data storage systems are critical for many applications as research and business become more data driven. Since metadata management is essential to system availability, multiple metadata Services are used to improve the availability of distributed storage systems. Past research has focused on the active/standby model, where each active Service has at least one Redundant idle backup. However, interruption of Service and even some loss of Service state may occur during a fail-over depending on the replication technique used. In addition, the replication overhead for multiple metadata Services can be very high. The research in this paper targets the symmetric active/active replication model, which uses multiple Redundant Service nodes running in virtual synchrony. In this model, Service node failures do not cause a fail-over to a backup and there is no disruption of Service or loss of Service state. A fast delivery protocol is further discussed to reduce the latency of the total order broadcast needed. The prototype implementation shows that metadata Service high availability can be achieved with an acceptable performance trade-off using the symmetric active/active metadata Service solution.
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Symmetric active/active metadata Service for highly available cluster storage systems
2007Co-Authors: Christian Engelmann, Xin Chen, Stephen L. ScottAbstract:In a typical distributed storage system, metadata is stored and managed by dedicated metadata servers. One way to improve the availability of distributed storage systems is to deploy multiple metadata servers. Past research focused on the active/standby model, where each active server has at least one Redundant idle backup. However, interruption of Service and loss of Service state may occur during a fail-over depending on the used replication technique. The research in this paper targets the symmetric active/active replication model using multiple Redundant Service nodes running in virtual synchrony. In this model, Service node failures do not cause a fail-over to a backup and there is no disruption of Service or loss of Service state. We use a fast delivery protocol to reduce the latency of total order broadcast. Our prototype implementation shows that high availability of metadata servers can be achieved with an acceptable performance trade-off using the active/active metadata server solution.
A V Bogatyrev - One of the best experts on this subject based on the ideXlab platform.
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Model and Interaction Efficiency of Computer Nodes Based on Transfer Reservation at Multipath Routing
2019 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF), 2019Co-Authors: V A Bogatyrev, S V Bogatyrev, A V BogatyrevAbstract:The possibilities of increasing the efficiency of Redundant Service requests by a sequence of nodes of a multilevel info-communication system are investigated. The efficiency of multi-path Service of requests is shown, in which, with a sequential receipt of a request for each level, a given number of copies are formed with their distribution for servicing between Redundant nodes of the corresponding level. A copy of the request made first is sent for back-up Service to the next level of the system, the remaining copies are destroyed. The effectiveness of the proposed Service organization is determined in comparison with the option in which the formation of copies takes place only until the request for the first level is received, and for each of them, the path is written as a sequence of nodes at different levels involved in the Service.
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analysis of the timeliness of Redundant Service in the system of the parallel series connection of nodes with unlimited queues
2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF), 2018Co-Authors: A V Bogatyrev, S V Bogatyrev, V A BogatyrevAbstract:The possibilities of increasing the effectiveness of multi-level infocommunication systems in multi-stage Redundant Service of requests that critical to delays in queues are researched. Existence of optimum redundary rate of requests depending on loading of system and restrictions for an allowed time of waiting in queues is shown.
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Efficiency of Redundant Service with Destruction of Expired and Irrelevant Request Copies in Real-Time Clusters
Communications in Computer and Information Science, 2016Co-Authors: V A Bogatyrev, S. A. Parshutina, N. A. Poptcova, A V BogatyrevAbstract:Possible ways of increasing the probability of timely and faultless execution of delay-sensitive requests in real-time clustered computing systems, when multiple copies of requests are created and served in different cluster nodes, are investigated. The proposed models for queueing and functional reliability prove the existence of scope of efficiency for Service disciplines with Redundant execution of copies of requests, when the probability of their prompt and error-free servicing can be increased significantly, despite the rise of load in the nodes. It was examined how the ways to arrange redundancy and the redundancy order affected timely and reliable servicing of requests, with possible faults and errors in the nodes. It was shown that destruction of expired copies, whose waiting time in the queue exceeded a given ultimate time, and copies which became irrelevant, after one of them had been processed, produced an essential enhancement of efficiency of the system.
V A Bogatyrev - One of the best experts on this subject based on the ideXlab platform.
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Model and Interaction Efficiency of Computer Nodes Based on Transfer Reservation at Multipath Routing
2019 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF), 2019Co-Authors: V A Bogatyrev, S V Bogatyrev, A V BogatyrevAbstract:The possibilities of increasing the efficiency of Redundant Service requests by a sequence of nodes of a multilevel info-communication system are investigated. The efficiency of multi-path Service of requests is shown, in which, with a sequential receipt of a request for each level, a given number of copies are formed with their distribution for servicing between Redundant nodes of the corresponding level. A copy of the request made first is sent for back-up Service to the next level of the system, the remaining copies are destroyed. The effectiveness of the proposed Service organization is determined in comparison with the option in which the formation of copies takes place only until the request for the first level is received, and for each of them, the path is written as a sequence of nodes at different levels involved in the Service.
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analysis of the timeliness of Redundant Service in the system of the parallel series connection of nodes with unlimited queues
2018 Wave Electronics and its Application in Information and Telecommunication Systems (WECONF), 2018Co-Authors: A V Bogatyrev, S V Bogatyrev, V A BogatyrevAbstract:The possibilities of increasing the effectiveness of multi-level infocommunication systems in multi-stage Redundant Service of requests that critical to delays in queues are researched. Existence of optimum redundary rate of requests depending on loading of system and restrictions for an allowed time of waiting in queues is shown.
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EFFICIENCY OF Redundant QUERY EXECUTION IN MULTI-CHANNEL Service SYSTEMS
Saint Petersburg National Research University of Information Technologies Mechanics and Optics (ITMO University), 2016Co-Authors: V A Bogatyrev, I. A. SlastikhinAbstract:Subject of Research.The paper deals with analysis of the effectiveness of Redundant queries based on untrusted computing in computer systems, represented by multi-channel queuing systems with a common queue. The objective of research is the possibility of increasing the efficiency of Service requests while performing Redundant copies of requests in different devices of a multi-channel system under conditions of calculations unreliability. The Redundant Service of requests requires the infallibility of its implementation at least in one of the devices.Method. We have considered estimation of the average time spent in the system with and without the use of Redundant requests at the presentation of a simple queuing model of the M / M / n type to analyze the effectiveness of Redundant Service of requests. Presented evaluation of the average waiting time in the Redundant queries is the upper one, since it ignores the possibility of reducing the average waiting time as a result of the spread of the probability of time querying at different devices. The integrated efficiency of Redundant Service of requests is defined based on the multiplicative index that takes into account the infallibility of calculations and the average time allowance with respect to the maximum tolerated delay of Service. Evaluation of error-free computing at reserved queries is received at the requirement of faultless execution of at least one copy of the request. Main Results. We have shown that the reservation of requests gives the gain in efficiency of the system at low demand rate (load). We have defined the boundaries of expediency (efficiency) for Redundant Service of requests. We have shown the possibility of the effectiveness increasing of the adaptive changes in the multiplicity of the reservation of requests, depending on the intensity of the flow of requests. We have found out that the choice of Service discipline in information Service systems is largely determined by the economic efficiency of information Services, estimated by the profit from the error-free provision of information Services obtained per time unit (rate of profit). We have demonstrated the existence of an efficiency area of information Services at the Redundant Service of requests under failures and errors. We have determined the flow rate threshold of requests below which a Redundant Service of requests is appropriate. Practical Relevance The results presented in the paper can be used in the computer systems design including the systems providing information Services
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Efficiency of Redundant Service with Destruction of Expired and Irrelevant Request Copies in Real-Time Clusters
Communications in Computer and Information Science, 2016Co-Authors: V A Bogatyrev, S. A. Parshutina, N. A. Poptcova, A V BogatyrevAbstract:Possible ways of increasing the probability of timely and faultless execution of delay-sensitive requests in real-time clustered computing systems, when multiple copies of requests are created and served in different cluster nodes, are investigated. The proposed models for queueing and functional reliability prove the existence of scope of efficiency for Service disciplines with Redundant execution of copies of requests, when the probability of their prompt and error-free servicing can be increased significantly, despite the rise of load in the nodes. It was examined how the ways to arrange redundancy and the redundancy order affected timely and reliable servicing of requests, with possible faults and errors in the nodes. It was shown that destruction of expired copies, whose waiting time in the queue exceeded a given ultimate time, and copies which became irrelevant, after one of them had been processed, produced an essential enhancement of efficiency of the system.