The Experts below are selected from a list of 28986 Experts worldwide ranked by ideXlab platform
H Levendel - One of the best experts on this subject based on the ideXlab platform.
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Availability Requirement for a fault management server in high Availability communication systems
IEEE Transactions on Reliability, 2003Co-Authors: H LevendelAbstract:This paper investigates the Availability Requirement for the fault management server in high-Availability communication systems. This study shows that the Availability of the fault management server does not need to be 99.999% in order to guarantee a 99.999% system Availability, as long as the fail-safe ratio (the probability that the failure of the fault management server does not bring down the system) and the fault coverage ratio (probability that the failure in the system can be detected and recovered by the fault management server) are sufficiently high. Tradeoffs can be made among the Availability of the fault management server, the fail-safe ratio, and the fault coverage ratio to optimize system Availability. A cost-effective design for the fault management server is proposed.
Hussein T. Mouftah - One of the best experts on this subject based on the ideXlab platform.
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Spare capacity reprovisioning for high Availability shared backup path protection connections
Computer Communications, 2010Co-Authors: Qi Guo, Janos Tapolcai, Hussein T. MouftahAbstract:Shared backup path protection (SBPP) has been widely studied in the Generalized MPLS (GMPLS) networks due to its efficient spare capacity sharing as well as simplicity and flexibility in service provisioning. This paper presents a novel Availability evaluation strategy for the end-to-end (E2E) Availability of an SBPP connection by considering up to two simultaneous failures, where the sequence of failures in a failure pattern is considered. To minimize the redundancy while meeting the E2E Availability Requirement, partial restoration is defined and embedded in the developed model, by which a novel parameter, called a protection level, is manipulated. Based on the proposed Availability model, two Linear Program (LP) formulations are introduced, which aim to perform spare capacity reprovisioning along each link for dynamic allocation of SBPP connections under either failure-dependent or failure-independent policies. Extensive simulations are conducted to validate the proposed Availability model and demonstrate the effectiveness of the spare capacity reprovisioning architecture. The proposed Availability-aware spare capacity reprovisioning approaches are then implemented on top of a well known survivable routing scheme - Successive Survivable Routing (SSR), where the spare capacity saving ratio is taken as the performance measure. We will show that the proposed spare capacity reprovisioning framework is an effective approach for achieving the GMPLS-based recovery in packet-switched networks.
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Availability constrained shared backup path protection sbpp for gmpls based spare capacity reprovisioning
International Conference on Communications, 2007Co-Authors: Qi Guo, Anwar Haque, Hussein T. MouftahAbstract:Shared-backup path protection (SBPP) has been widely studied in the GMPLS networks due to its efficient spare capacity sharing and flexibility in service provisioning. This paper presents a model for evaluating the end-to-end (E2E) Availability of an SBPP connection by assuming that no more than two simultaneous failures could possibly occur in the network. To minimize the redundancy while meeting the E2E Availability Requirement, a framework of partial restoration from any unexpected failure is created. Based on the proposed Availability model, a novel Linear Program (LP) formulation is introduced, which aims to perform the spare capacity allocation for SBPP connections. A new Availability-aware spare capacity reprovisioning (SCR) architecture is then introduced for dynamic provisioning of SBPP connections. Extensive simulations are conducted to validate the proposed Availability model and demonstrate the effectiveness of the SCR architecture.
Tammi Kari - One of the best experts on this subject based on the ideXlab platform.
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Hybrid electric topology for short sea ships with high auxiliary power Availability Requirement
'Elsevier BV', 2021Co-Authors: Ritari Antti, Huotari Janne, Halme Jukka, Tammi KariAbstract:The inclusion of a battery system for a diesel mechanical short sea ship was investigated. The main benefits of the battery were assumed to emerge from shaving thruster generated power peaks, rather than starting additional generating sets to accommodate the power demand and additionally from replacing a diesel engine as a reserve power source. To support the analysis, an auxiliary engine power output dataset of a roll-on/roll-off passenger ferry operating in the Baltic Sea was acquired. Required capacity for the battery system was derived by considering power Availability Requirements and battery safety margins for performance deterioration. A multi-period mixed-integer linear programming model was developed to derive a globally optimal power management strategy for the auxiliary engines and the battery, with the goal of minimizing the battery installation total cost. The battery system was found to reduce fuel oil consumption by 257.5 tons annually due to improved auxiliary engine efficiency alone. Furthermore, the battery system total cost advantage was found to vary from -€0.61 to €2.82 million during the ten-year investment period, depending on fuel oil and battery system costs applied in the modeling. For the studied case ship, the hybrid electric topology was concluded to be economically feasible.Peer reviewe
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Hybrid electric topology for short sea ships with high auxiliary power Availability Requirement
'Elsevier BV', 2021Co-Authors: Ritari Antti, Huotari Janne, Halme Jukka, Tammi KariAbstract:The inclusion of a battery system for a diesel mechanical short sea ship was investigated. The main benefits of the battery were assumed to emerge from shaving thruster generated power peaks, rather than starting additional generating sets to accommodate the power demand and additionally from replacing a diesel engine as a reserve power source. To support the analysis, an auxiliary engine power output dataset of a roll-on/roll-off passenger ferry operating in the Baltic Sea was acquired. Required capacity for the battery system was derived by considering power Availability Requirements and battery safety margins for performance deterioration. A multi-period mixed-integer linear programming model was constructed to derive a globally optimal power management strategy for the auxiliary engines and the battery, with the goal of minimizing the battery installation total cost. The battery system was found to reduce fuel oil consumption by 257.5 tons annually due to improved auxiliary engine efficiency alone. Furthermore, the battery system total cost advantage was found to vary from -€0.61 to €2.82 million during the ten-year investment period, depending on fuel oil and battery system costs applied in the modeling. For the studied case ship, the hybrid electric topology was concluded to be economically feasible.Peer reviewe
Qi Guo - One of the best experts on this subject based on the ideXlab platform.
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Spare capacity reprovisioning for high Availability shared backup path protection connections
Computer Communications, 2010Co-Authors: Qi Guo, Janos Tapolcai, Hussein T. MouftahAbstract:Shared backup path protection (SBPP) has been widely studied in the Generalized MPLS (GMPLS) networks due to its efficient spare capacity sharing as well as simplicity and flexibility in service provisioning. This paper presents a novel Availability evaluation strategy for the end-to-end (E2E) Availability of an SBPP connection by considering up to two simultaneous failures, where the sequence of failures in a failure pattern is considered. To minimize the redundancy while meeting the E2E Availability Requirement, partial restoration is defined and embedded in the developed model, by which a novel parameter, called a protection level, is manipulated. Based on the proposed Availability model, two Linear Program (LP) formulations are introduced, which aim to perform spare capacity reprovisioning along each link for dynamic allocation of SBPP connections under either failure-dependent or failure-independent policies. Extensive simulations are conducted to validate the proposed Availability model and demonstrate the effectiveness of the spare capacity reprovisioning architecture. The proposed Availability-aware spare capacity reprovisioning approaches are then implemented on top of a well known survivable routing scheme - Successive Survivable Routing (SSR), where the spare capacity saving ratio is taken as the performance measure. We will show that the proposed spare capacity reprovisioning framework is an effective approach for achieving the GMPLS-based recovery in packet-switched networks.
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Availability constrained shared backup path protection sbpp for gmpls based spare capacity reprovisioning
International Conference on Communications, 2007Co-Authors: Qi Guo, Anwar Haque, Hussein T. MouftahAbstract:Shared-backup path protection (SBPP) has been widely studied in the GMPLS networks due to its efficient spare capacity sharing and flexibility in service provisioning. This paper presents a model for evaluating the end-to-end (E2E) Availability of an SBPP connection by assuming that no more than two simultaneous failures could possibly occur in the network. To minimize the redundancy while meeting the E2E Availability Requirement, a framework of partial restoration from any unexpected failure is created. Based on the proposed Availability model, a novel Linear Program (LP) formulation is introduced, which aims to perform the spare capacity allocation for SBPP connections. A new Availability-aware spare capacity reprovisioning (SCR) architecture is then introduced for dynamic provisioning of SBPP connections. Extensive simulations are conducted to validate the proposed Availability model and demonstrate the effectiveness of the SCR architecture.
I Levendel - One of the best experts on this subject based on the ideXlab platform.
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Availability Requirement for a fault management server in high Availability communication systems
International Parallel and Distributed Processing Symposium, 2002Co-Authors: I LevendelAbstract:In this paper, we investigate the Availability Requirement for the fault management server in high-Availability communication systems. According to our study, we find that the Availability of the fault management server does not need to be 99.999% in order to guarantee a 99.999% system Availability as long as the fail-safe ratio (the probability that the failure of the fault management server will not bring the system down) and the fault coverage ratio (the probability that the failure in the system can be detected and recovered by the fault management server) are sufficiently high. Tradeoffs can be made among the Availability of the fault management server, the fail-safe ratio and the fault coverage ratio to optimize system Availability. A cost-effective design for the fault management server is proposed in this paper.
