Characterizing instruction latency for speculative issue SMPs: a case study of varying memory system performance on the SPLASH-2 benchmarks

2002 ◽  
Author(s):  
B. Grayson ◽  
C. Chase
Keyword(s):  
System Performance ◽  
Memory System ◽  
Splash 2

scholarly journals An Adaptive Load Frequency Control for Power Systems with Renewable Energy Sources

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 573
Author(s):  
Mohamed Mokhtar ◽  
Mostafa I. Marei ◽  
Mariam A. Sameh ◽  
Mahmoud A. Attia
Keyword(s):  
Renewable Energy ◽  
Power Systems ◽  
System Performance ◽  
Frequency Control ◽  
Renewable Energy Sources ◽  
Adaptive Controller ◽  
Load Frequency Control ◽  
Energy Sources ◽  
Load Variations

The frequency of power systems is very sensitive to load variations. Additionally, with the increased penetration of renewable energy sources in electrical grids, stabilizing the system frequency becomes more challenging. Therefore, Load Frequency Control (LFC) is used to keep the frequency within its acceptable limits. In this paper, an adaptive controller is proposed to enhance the system performance under load variations. Moreover, the proposed controller overcomes the disturbances resulting from the natural operation of the renewable energy sources such as Wave Energy Conversion System (WECS) and Photovoltaic (PV) system. The superiority of the proposed controller compared to the classical LFC schemes is that it has auto tuned parameters. The validation of the proposed controller is carried out through four case studies. The first case study is dedicated to a two-area LFC system under load variations. The WECS is considered as a disturbance for the second case study. Moreover, to demonstrate the superiority of the proposed controller, the dynamic performance is compared with previous work based on an optimized controller in the third case study. Finally in the fourth case study, a sensitivity analysis is carried out through parameters variations in the nonlinear PV-thermal hybrid system. The novel application of the adaptive controller into the LFC leads to enhance the system performance under disturbance of different sources of renewable energy. Moreover, a robustness test is presented to validate the reliability of the proposed controller.

scholarly journals QHAR: Q-Holonic-Based ARchitecture for Self-Configuration of Cyber–Physical Production Systems

2021 ◽  
Vol 11 (19) ◽  
pp. 9013
Author(s):  
Douha Macherki ◽  
Thierno M. L. Diallo ◽  
Jean-Yves Choley ◽  
Amir Guizani ◽  
Maher Barkallah ◽  
...  
Keyword(s):  
Decentralized Control ◽  
System Performance ◽  
Production Systems ◽  
Control Level ◽  
Centralized Control ◽  
Four Dimensions ◽  
Potential Capacity ◽  
Heterarchical Control ◽  
Cyber Physical Production Systems

Production systems must be able to adapt to increasingly frequent internal and external changes. Cyber-Physical Production Systems (CPPS), thanks to their potential capacity for self-reconfiguration, can cope with this need for adaptation. To implement the self-reconfiguration functionality in economical and safe conditions, CPPS must have appropriate tools and contextualized information. This information can be organized in the form of an architecture. In this paper, after the analysis of several holonic and nonholonic architectures, we propose a holonic architecture that allows for reliable and efficient reconfiguration. We call this architecture QHAR (Q-Holonic-based ARchitecture). QHAR is constructed based on the idea of a Q-holon, which has four dimensions (physical, cyber, human, and energy) and can exchange three flows (energy, data, and materials). It is a generic Holon that can represent any entity or actor of the supply chain. The QHAR is structured in three levels: centralized control level, decentralized control level, and execution level. QHAR implements the principle of an oligarchical control architecture by deploying both hierarchical and heterarchical control approaches. This ensures the overall system performance and reactivity to hazards. The proposed architecture is tested and validated on a case study.

The Case for Combining Pump Maintenance and Systematic Upgrading

2008 ◽  
Author(s):  
Heinz P. Bloch ◽  
Robert Bluse ◽  
James Steiger
Keyword(s):  
System Performance ◽  
Current System ◽  
Highly Qualified ◽  
Centrifugal Pumps ◽  
Term Operation ◽  
Performance Requirements ◽  
Periodic Maintenance ◽  
Work Supports

Virtually, all industrial machinery requires periodic maintenance for dependable long-term operation. In fact, the very term “maintenance” is defined as keeping machines in the as-designed or as-purchased and manufactured condition. At issue is whether the equipment owner’s profitability objectives are best served by “maintaining only”, or by judiciously combining maintenance and upgrading tasks. Assuming the answer favors combining maintenance and upgrading, the question arises whether an intelligent and well thought-out combination of maintenance and upgrading should be entrusted only to the original equipment manufacturer (OEM), or if qualified non-OEMs should be considered also. The co-authors would like to offer their answer to the question. Experience shows that a highly qualified independent rebuild shop with demonstrated capabilities and experienced personnel can offer high-quality upgrades that improve both uptime and efficiency. Such a shop can do so consistent with current system performance requirements. With the considerable consolidations in the pump industry, the distinct possibility exists that the OEM is not able to offer the same engineering competence he previously had and that independent shops should be considered. This presentation deals with a case study and details where such upgrading was being planned, implemented, and verified to have had the desired results. It further explains the role played by competent pump rebuild shops (we chose to call them “CPRS”) in these important endeavors. Our work supports the premise that rebuilding a vintage process pump to original OEM specifications makes no sense, given current pump rebuilding technology and changes to the system performance that occur over time. We find compelling reasons to systematically upgrade the efficiency and potential run length of large centrifugal pumps. Of course, this upgrading must be pre-planned and then carried out during a future maintenance outage.

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