In this paper, we develop a new class of time division multiple access schemes for bi-directional multiuser communications in cooperative amplify-and-forward relay networks. the proposed schemes enable a flexible trad...
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ISBN:
(纸本)9781467310710
In this paper, we develop a new class of time division multiple access schemes for bi-directional multiuser communications in cooperative amplify-and-forward relay networks. the proposed schemes enable a flexible trade-off between spectral efficiency and suppression of multiuser interference. the relay weights are chosen to maximize the minimum received quality-of-service of all the users under constraints on the individual and the total power at the relays. simulation results demonstrate that the selection of the scheme has a considerable impact on the achieved throughput of the relay network.
the suitability of the Time Warp mechanism to perform simulations with real-time constraints is examined. A model for Time Warp is developed that accounts for overheads such as state saving, state restoration, and sen...
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ISBN:
(纸本)1565550552
the suitability of the Time Warp mechanism to perform simulations with real-time constraints is examined. A model for Time Warp is developed that accounts for overheads such as state saving, state restoration, and sending and transmitting positive and negative messages. A criterion called R-schedulability is defined to indicate whether or not computations can meet real-time deadlines. It is shown that if false events (events that will be rolled back or cancelled later) are generated, and there are no committed events with timestamps equal to those of the false events, Time Warp cannot meet the R-schedulability criterion. Further, if aggressive cancellation is used, scheduling guarantees still cannot be made even in the absence of such false events. However, Time Warp using lazy cancellation is shown to be R-schedulable provided such false events do not exist. Finally, based on these results, bounds on the execution time of a Time Warp simulation are derived.
Although there exist many approaches for classification of computer architectures, no system is able to distinguish parallel computers adequately yet. the first part of this paper is a brief survey of the main charact...
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ISBN:
(纸本)0769500595
Although there exist many approaches for classification of computer architectures, no system is able to distinguish parallel computers adequately yet. the first part of this paper is a brief survey of the main characteristics of various parallel architecture concepts and several approaches of classification. We realized that the idea of defining a sharp classification system is questionable in the world of parallel computing. But we also recognized important structural similarities of computing systems. So we introduce a modeling system, called rho (recursive hierarchical objects), which allows to describe the structure Of various computing systems hierarchically. However we do not aim at a new classification system but at a scheme for modeling parallel architectures.
this at-tide aims at introducing SYD, a tool for the generation of time-stamps synchronized withthe Universal Time Coordinate: the implementation includes an NTP client and is written in Java(1). Possible application...
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ISBN:
(纸本)0769500595
this at-tide aims at introducing SYD, a tool for the generation of time-stamps synchronized withthe Universal Time Coordinate: the implementation includes an NTP client and is written in Java(1). Possible applications include (but are not limited to) the measurement of the performance of distributed applications, their debugging, and Me implementation of real-time requirements in distributed systems. the features that characterize SYD are its portability across platforms, the low cost in terms of network overhead, and the absence of interference with other applications running on the same host (SYD does not synchronize the system clock!);In this paper, we prove that the choice of Java does impact on the performance of the tool, when compared with an equivalent application written inC. SYD is available on the Web as public domain software.
the proceedings contain 5 papers. the topics discussed include: modeling and analysis of the impact of texturing angles on doping profiles in ion implanted N-type solar cells;study about the rigor of tightness tests a...
ISBN:
(纸本)9788885741386
the proceedings contain 5 papers. the topics discussed include: modeling and analysis of the impact of texturing angles on doping profiles in ion implanted N-type solar cells;study about the rigor of tightness tests and the existance of an empirical constant to validate theoretical simulations to approximate the real model;pollution routing problem with time window and split delivery;and optimizing energy efficiency in distributed mHealth networks.
We present a new conservative event-synchronization protocol, time-based synchronization, for parallel discrete-event simulation of mobile ad hoc wireless networks. Simulators that use our protocol proceed at a scaled...
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ISBN:
(纸本)0769520367
We present a new conservative event-synchronization protocol, time-based synchronization, for parallel discrete-event simulation of mobile ad hoc wireless networks. Simulators that use our protocol proceed at a scaled version of real time and send messages that correspond only to transmissions in the simulated network. We show that such simulators can maintain a constant execution time even as the sizes of the networks that they simulate grow. Moreover we show that these simulators, when executed on a custom parallel architecture, are capable of simulating many networks faster than real time.
the proceedings contain 16 papers. the topics discussed include: ZerOBNL: a framework for distributed and reproducible co-simulation;towards an assisted simulation planning for co-simulation of cyber-physical energy s...
ISBN:
(纸本)9781728106373
the proceedings contain 16 papers. the topics discussed include: ZerOBNL: a framework for distributed and reproducible co-simulation;towards an assisted simulation planning for co-simulation of cyber-physical energy systems;cross-platform comparison of standard power system components used in real time simulation;over current relay modeling using modelica with cross-verification against a validated model;ExSol: collaboratively assessing cybersecurity risks for protecting energy delivery systems;a digital twin for cyber-physical energy systems;automated parameter identification and calibration for the Itaipu power generation system using modelica, FMI, and RaPId;and collaborative simulation of heterogeneous components as a means toward a more comprehensive analysis of smart grids.
the proceedings contain 3 papers. the topics discussed include: the benefits of service choreography for data-intensive computing;rebuilding Debian using distributed computing;and deployment and management of large pl...
ISBN:
(纸本)9781605585888
the proceedings contain 3 papers. the topics discussed include: the benefits of service choreography for data-intensive computing;rebuilding Debian using distributed computing;and deployment and management of large planar reflectarray antennas simulation on grid.
the proceedings contain 11 papers. the topics discussed include: effective dynamic load balance using space-filling curves for large-scale SPH simulations on GPU-rich supercomputers;towards fast scalable solvers for c...
ISBN:
(纸本)9781509052226
the proceedings contain 11 papers. the topics discussed include: effective dynamic load balance using space-filling curves for large-scale SPH simulations on GPU-rich supercomputers;towards fast scalable solvers for charge equilibration in molecular dynamics applications;left-preconditioned communication-avoiding conjugate gradient methods for multiphase CFD simulations on the K computer;the gyrokinetic particle simulation of fusion plasmas on tianhe-2 supercomputer;extremely scalable algorithm for 108-atom quantum material simulation on the full system of the K computer;performance scaling variability and energy analysis for a resilient ULFM-based PDE solver;batched generation of incomplete sparse approximate inverses on GPUs;a massively paralleldistributed n-body application implemented with HPX;randomized sketching for large-scale sparse ridge regression problems;optimizing plasma eigensolver on large shared memory system;and on Monte Carlo hybrid methods for linear algebra.
the two main approaches to parallel discrete event simulation - conservative and optimistic - are likely to encounter some limitations when the size and complexity of the simulation system increases. For such large sc...
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ISBN:
(纸本)1565550552
the two main approaches to parallel discrete event simulation - conservative and optimistic - are likely to encounter some limitations when the size and complexity of the simulation system increases. For such large scale simulations, the conservative approach appears to be limited by blocking overhead and sensitivity to lookahead, whereas the optimistic approach may become prone to cascading rollbacks, state saving overhead, and demands for larger memory space. these drawbacks restrict the synchronization schemes based on each of the two approaches from scaling up. A combined approach may resolve these limitations, while preserving and utilizing potential advantages of each method. However, the schemes proposed so far integrate the two views at the same level, i.e. local to a logical process, and hence may not be able to fully solve the problems. In this paper we propose the Local Time Warp method for parallel discrete-event simulation and present a novel synchronization scheme for it called HCTW. the new scheme hierarchically combines a Conservative Time Window algorithm with Time Warp and aims at reducing cascade rollbacks, sensitivity to lookahead, and the scalability problems. Local Time Warp is believed to be suitable for parallel machines equipped withthousands of processors and thus an appropriate candidate for simulation of large and complex systems.
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