The Experts below are selected from a list of 2388 Experts worldwide ranked by ideXlab platform

Vidhyacharan Bhaskar - One of the best experts on this subject based on the ideXlab platform.

  • A Closed Queuing Network model with single servers for multi-threaded architecture
    Applied Mathematical Modelling, 2009
    Co-Authors: Vidhyacharan Bhaskar
    Abstract:

    In this paper, a Closed Queuing Network model with single servers for each queue is proposed to model dataflow in a multi-threaded architecture. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A Closed Queuing Network model is suitable for large number of job arrivals. The normalization constant is derived using a recursive algorithm for the given model. State diagrams are drawn from the Closed Queuing Network model, and the steady-state balance equations are derived from it. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the Closed Queuing Network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived.

  • A Closed Queuing Network model with multiple servers for multi-threaded architecture
    Computer Communications, 2008
    Co-Authors: Vidhyacharan Bhaskar
    Abstract:

    In this paper, a Closed Queuing Network model with multiple servers has been proposed to model dataflow in a multi-threaded architecture. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A Closed Queuing Network model is suitable for large number of job arrivals. The normalization constant is derived using a recursive algorithm for the given model. State diagrams are drawn from the Closed Queuing Network model with multiple servers, and the steady-state balance equations are derived from it. Performance measures such as response times and system throughput are derived and plotted against the total number of processors in the Closed Queuing Network model. Other important performance measures like processor utilizations, queue lengths, waiting times and relative utilizations are also derived.

  • A hybrid Closed Queuing Network approach to model dataflow in Networked distributed processors
    Computer Communications, 2008
    Co-Authors: Vidhyacharan Bhaskar, Kondo H. Adjallah
    Abstract:

    In this paper, a hybrid Closed Queuing Network model has been proposed to model dataflow in Networked distributed processing systems. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A Closed Queuing Network model is suitable for large number of job arrivals. Both single server and multiple server models are discussed. The normalization constant is derived using a recursive algorithm for the given model. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the Closed Queuing Network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived.

  • A hybrid Closed Queuing Network model for multi-threaded dataflow architecture
    Computers & Electrical Engineering, 2005
    Co-Authors: Vidhyacharan Bhaskar
    Abstract:

    In this paper, a Closed Queuing Network model with both single and multiple servers has been proposed to model dataflow in a multi-threaded architecture. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A Closed Queuing Network model is suitable for large number of job arrivals. The normalization constant is derived using a recursive algorithm for the given model. State diagrams are drawn from the hybrid Closed Queuing Network model, and the steady-state balance equations are derived from it. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the Closed Queuing Network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived.

  • Dataflow modelling in distributed diagnostic processing systems: a Closed Queuing Network model with single servers
    International Journal of Pure and Applied Mathematics, 2005
    Co-Authors: Vidhyacharan Bhaskar, Kondo H. Adjallah, Laurie Joiner
    Abstract:

    In this paper, a Closed Queuing Network model with single servers has been proposed to model dataflow in distributed diagnosticprocessing systems. Multi-threading is useful in reducing the latency by switching among a set of threads in order to improve the processor utilization. Two sets of processors, synchronization and execution processors exist. Synchronization processors handle load/store operations and execution processors handle arithmetic/logic and control operations. A Closed Queuing Network model is suitable for large number of job arrivals. The normalization constant is derived using a recursive algorithm for the given model. Performance measures such as average response times and average system throughput are derived and plotted against the total number of processors in the Closed Queuing Network model. Other important performance measures like processor utilizations, average queue lengths, average waiting times and relative utilizations are also derived.

Mohamed Haddar - One of the best experts on this subject based on the ideXlab platform.

  • Model reduction for studying a Bike Sharing System as a Closed Queuing Network
    2018
    Co-Authors: Bacem Samet, Florent Couffin, Maher Barkallah, Marc Zolghadri, Mohamed Haddar
    Abstract:

    The users of a B2C Bike Sharing System are satisfied if they find always free bikes and free docks at the stations. Modeling such systems is challenging because they are large-scaled and characterized by their stochastic dynamic. To study the performance of a BSS, we rely on a Queuing model solved by the Entropy Maximization. In this paper, we study the possibility of aggregating a number of stations in a single virtual station to reduce the complexity of the model and its resolution. Experiments are performed to qualify impacts of the model reduction on the accuracy of the obtained results.

  • Performance analysis and improvement of the Bike Sharing System Using Closed Queuing Networks With Blocking Mechanism
    Sustainability, 2018
    Co-Authors: Bacem Samet, Florent Couffin, Maher Barkallah, Marc Zolghadri, Mohamed Haddar
    Abstract:

    The Bike Sharing System is a sustainable urban transport solution that consists of a fleet of bikes placed in various stations. Users will be satisfied if they find available bikes at their departure station and free docks at the destination. Despite the regulation operations of the system provider (i.e., redistribution of bikes by truck) deeper modifications (bike fleet size or station capacity) are often necessary to ensure a satisfactory service rate. In this paper, we model a sub-graph of a Bike Sharing System using the Closed Queuing Network with a Repetitive-Service-Random-Destination blocking mechanism. This model is solved using the Maximum Entropy Method. This model faithfully reproduces the system dynamics considering the limited capacity of stations. We analyze the performance, particularly, via an overall performance indicator of the system. The various control and monitoring decisions (fleet-size, capacity of stations, incoming and outgoing flow of bikes) are applied to find out the best performance levels. The results demonstrate that the overall performance is robust enough regarding the fleet size changes but it degrades with the increase of the stations' capacity. Finally, the arrival and departure flows control is an efficient and powerful operational leverage.

Kishor S. Trivedi - One of the best experts on this subject based on the ideXlab platform.

  • Multiprocessor performability analysis
    IEEE Transactions on Reliability, 1993
    Co-Authors: N. Lopez-benitez, Kishor S. Trivedi
    Abstract:

    Performability models of multiprocessor systems and their evaluation are presented. Two cases in which hierarchical modeling is applied are examined. Modified stochastic Petri net (MSPN)-based fault models of processor arrays, and a fault handling model to account for near coincident, permanent, transient, and intermittent faults are discussed. Performability results based on capacity-based reward assignments are reported. A simple MSPN-based model for multiprocessor systems, is introduced, and a Closed Queuing Network to derive performance rewards is discussed. Several multiprocessor configurations are compared. >

Bacem Samet - One of the best experts on this subject based on the ideXlab platform.

  • Model reduction for studying a Bike Sharing System as a Closed Queuing Network
    2018
    Co-Authors: Bacem Samet, Florent Couffin, Maher Barkallah, Marc Zolghadri, Mohamed Haddar
    Abstract:

    The users of a B2C Bike Sharing System are satisfied if they find always free bikes and free docks at the stations. Modeling such systems is challenging because they are large-scaled and characterized by their stochastic dynamic. To study the performance of a BSS, we rely on a Queuing model solved by the Entropy Maximization. In this paper, we study the possibility of aggregating a number of stations in a single virtual station to reduce the complexity of the model and its resolution. Experiments are performed to qualify impacts of the model reduction on the accuracy of the obtained results.

  • Performance analysis and improvement of the Bike Sharing System Using Closed Queuing Networks With Blocking Mechanism
    Sustainability, 2018
    Co-Authors: Bacem Samet, Florent Couffin, Maher Barkallah, Marc Zolghadri, Mohamed Haddar
    Abstract:

    The Bike Sharing System is a sustainable urban transport solution that consists of a fleet of bikes placed in various stations. Users will be satisfied if they find available bikes at their departure station and free docks at the destination. Despite the regulation operations of the system provider (i.e., redistribution of bikes by truck) deeper modifications (bike fleet size or station capacity) are often necessary to ensure a satisfactory service rate. In this paper, we model a sub-graph of a Bike Sharing System using the Closed Queuing Network with a Repetitive-Service-Random-Destination blocking mechanism. This model is solved using the Maximum Entropy Method. This model faithfully reproduces the system dynamics considering the limited capacity of stations. We analyze the performance, particularly, via an overall performance indicator of the system. The various control and monitoring decisions (fleet-size, capacity of stations, incoming and outgoing flow of bikes) are applied to find out the best performance levels. The results demonstrate that the overall performance is robust enough regarding the fleet size changes but it degrades with the increase of the stations' capacity. Finally, the arrival and departure flows control is an efficient and powerful operational leverage.

N. Lopez-benitez - One of the best experts on this subject based on the ideXlab platform.

  • Multiprocessor performability analysis
    IEEE Transactions on Reliability, 1993
    Co-Authors: N. Lopez-benitez, Kishor S. Trivedi
    Abstract:

    Performability models of multiprocessor systems and their evaluation are presented. Two cases in which hierarchical modeling is applied are examined. Modified stochastic Petri net (MSPN)-based fault models of processor arrays, and a fault handling model to account for near coincident, permanent, transient, and intermittent faults are discussed. Performability results based on capacity-based reward assignments are reported. A simple MSPN-based model for multiprocessor systems, is introduced, and a Closed Queuing Network to derive performance rewards is discussed. Several multiprocessor configurations are compared. >