摘要 :
Mobile platforms are increasingly using Heterogeneous Multiprocessor Systems-on-Chip (HMPSoCs) with differentiated processing cores and GPUs to achieve high performance for graphics-intensive applications such as mobile games. Tra...
展开
Mobile platforms are increasingly using Heterogeneous Multiprocessor Systems-on-Chip (HMPSoCs) with differentiated processing cores and GPUs to achieve high performance for graphics-intensive applications such as mobile games. Traditionally, separate CPU and GPU governors are deployed in order to achieve energy efficiency through Dynamic Voltage Frequency Scaling (DVFS) but miss opportunities for further energy savings through coordinated system-level application of DVFS. We present a cooperative CPU-GPU DVFS strategy (called Co-Cap) that orchestrates energy-efficient CPU and GPU DVFS through synergistic CPU and GPU frequency capping to avoid frequency overprovisioning while maintaining desired performance. Unlike traditional approaches that target a narrow set of mobile games, our Co-Cap approach is applicable across a wide range of microbenchmarks and mobile games. Our methodology employs a systematic training phase using fine-grained refinement steps with evaluations of frequency capping tables followed by a deployment phase, allowing deployment across a wide range of microbenchmarks and mobile games with varying graphics workloads. Our experimental results across multiple sets of over 200 microbenchmarks and 40 mobile games show that Co-Cap improves energy per frame by on average 8.9% (up to 18.3%) and 7.8% (up to 27.6%) (16.6% and 15.7% in CPU-dominant applications) and achieves minimal frames-per-second (FPS) loss by 0.9% and 0.85% (1.3% and 1.5% in CPU-dominant applications) on average in training and deployment sets, respectively, compared to the default CPU and GPU governors, with negligible overhead in execution time and power consumption on the ODROID-XU3 platform.
收起
摘要 :
Integrating large quantities of variable renewable electricity generation remains a political and operational challenge. One of the main obstacles in Europe to installing at least 200 GWs of power from variable renewable sources i...
展开
Integrating large quantities of variable renewable electricity generation remains a political and operational challenge. One of the main obstacles in Europe to installing at least 200 GWs of power from variable renewable sources is how to deal with the insufficient network capacity and the congestion that will result from new flow patterns. We model the current methodology for controlling congestion at international borders and compare its results, under varying penetrations of wind power, with models that simulate an integrated European network using nodal/localised marginal pricing. The nodal pricing simulations illustrate that congestion and price patterns vary considerably between wind scenarios and within countries, and that a nodal price regime could make better use of existing network capacity, introducing substantial operational cost savings and reducing marginal power prices in the majority of European countries.
收起
摘要 :
Hybrid Renewable Energy Systems (HRES) are increasingly used to improve the grid integration of wind power generators. The goal of this work is to propose a methodology to design a fuzzy logic based supervision of this new kind of...
展开
Hybrid Renewable Energy Systems (HRES) are increasingly used to improve the grid integration of wind power generators. The goal of this work is to propose a methodology to design a fuzzy logic based supervision of this new kind of production unit. A graphical modeling tool is proposed to facilitate the analysis and the determination of fuzzy control algorithms adapted to complex hybrid systems. To explain this methodology, the association of wind generators, decentralized generators and storage systems are considered for the production of electrical power. The methodology is divided in six steps covering the design of a supervisor from the system work specifications to an optimized implementation of the control. The performance of this supervisor is shown with the help of simulations. Finally, the application of this methodology to the supervision of different topologies of HRES is also proposed to bring forward the systematic dimension of the approach.
收起
摘要 :
More "green" power provided by Distributed Generation will enter into the European electricity network in the near future. In order to control the power flow and to ensure proper and secure operation of this future grid, with an i...
展开
More "green" power provided by Distributed Generation will enter into the European electricity network in the near future. In order to control the power flow and to ensure proper and secure operation of this future grid, with an increased level of the renewable power, new power electronic converters for grid connection of renewable sources are needed. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents an overview of an advanced power converter for universal and flexible power management that can enable the large scale-integration of dispersed generation into these future networks. The overall structure and the control requirements that are to be placed upon this converter are given. Furthermore, some possible applications as well as the benefits of using this converter are presented.
收起
摘要 :
Alongside innovative device, circuit, and microarchitecture level techniques to alleviate power and thermal problems in nanoscale CMOS-based integrated circuits (ICs), chip cooling could be an effective knob for power and thermal ...
展开
Alongside innovative device, circuit, and microarchitecture level techniques to alleviate power and thermal problems in nanoscale CMOS-based integrated circuits (ICs), chip cooling could be an effective knob for power and thermal management. This paper analyzes IC cooling while focusing on the practical temperature range of operation. Comprehensive analyses of chip cooling for various nanometer scale bulk-CMOS and Silicon-On-Insulator (SOI) technologies are presented. Unlike all previous works, this analysis employs a holistic approach (combines device, circuit and system level considerations) and also takes various electrothermal couplings between power dissipation, operating frequency and die temperature into account. While chip cooling always gives performance gain at the device and circuit level, it is shown that system level power defines a temperature limit beyond which cooling gives diminishing returns and an associated cost that may be prohibitive. A scaling analysis of this temperature limit is also presented. Furthermore, it is shown that on-chip thermal gradients cannot be mitigated by global chip cooling and that localized cooling can be more effective in removing hot-spots.
收起
摘要 :
A process for establishing an Integrated Management System (IMS) for operation and maintenance of the ETRR-2 reactor is initiated. Development and application of the IMS consider the usage of a graded approach in order to commensu...
展开
A process for establishing an Integrated Management System (IMS) for operation and maintenance of the ETRR-2 reactor is initiated. Development and application of the IMS consider the usage of a graded approach in order to commensurate the resources devoted to management system with the importance of an item/activity and the magnitude of the risks. Literatures have introduced different methods for the concept of graded approach which is very important in applying the management, safety and technical requirements. This paper provides an additional example for the methodology of applying such approach. It suggests a grading methodology and determines the considerations that need to be taken into account in grading the application of IMS requirements. The paper introduces a proposal for classification of items or activities in the ETRR-2 into four grades. Then gives a grading example of specific controls for maintenance of structures, systems and components (SSCs) in the plant and explains the management requirements appropriate for each grade. Finally, the approach is explained briefly using an application practice on the Standby Power Supply system of the plant as a case study.
收起
摘要 :
This work investigates how to balance the electricity supply and demand in a carbon-neutral northern Europe. Applying a cost-minimizing electricity system model including options to invest in eleven different flexibility measures,...
展开
This work investigates how to balance the electricity supply and demand in a carbon-neutral northern Europe. Applying a cost-minimizing electricity system model including options to invest in eleven different flexibility measures, and cost-efficient combinations of strategies to manage variations were identified. The results of the model were post-processed using a novel method to map the net load before and after flexibility measures were applied to reveal the contribution of each flexibility measure. The net load was mapped in the space spanned by the amplitude, duration and number of occurrences. The mapping shows that, depending on cost structure, flexibility measures contribute to reduce the net load in three different ways; (1) by reducing variations with a long duration but low amplitude, (2) by reducing variations with a high amplitude but short duration and low occurrence or (3) by reducing variations with a high amplitude, short duration and high occurrence. It was found that cost-efficient variation management was achieved by combining wind and solar power and by combining strategies (1–3) to manage the variations. The cost-efficient combination of strategies depends on electricity system context where electricity trade, flexible hydrogen and heat production (1) manage the majority of the variations in regions with good conditions for wind power while stationary batteries (3) were the main contributors in regions with good conditions for solar power.
收起
摘要 :
This article proposes a novel embedded communication strategy for in-home energy routers (IHERs). It is based on the power/signal dual modulation (PSDM) principle and applied in the small-scale community energy local area network ...
展开
This article proposes a novel embedded communication strategy for in-home energy routers (IHERs). It is based on the power/signal dual modulation (PSDM) principle and applied in the small-scale community energy local area network (E-LAN). The proposed communication strategy multiplexes power converters as data transmitters, and thus high cooperation and synchronization between power flow and information flow are achieved. In addition, system reliability is enhanced since communication module has practically the same reliability as the power module. A typical IHER’s structure and operation principles are presented, based on which the detailed design of embedded communication is proposed. For distributed power management of community E-LAN, both intra-IHER communication and inter-IHERs communication are involved, and their channels are modeled mathematically. IHER interconnection interface converters (IICs) play a significant role in power exchange between IHERs, and their operation modes are analyzed in detail. Finally, an experimental prototype is built to validate the feasibility of the proposed method.
收起
摘要 :
Growing load factors in winter and summer peaks are a serious problem faced by the Spanish electric energy system. This has led to the extensive use of peak load plants and thus to higher costs for the whole system. Wind energy re...
展开
Growing load factors in winter and summer peaks are a serious problem faced by the Spanish electric energy system. This has led to the extensive use of peak load plants and thus to higher costs for the whole system. Wind energy represents a strongly increasing percentage of overall electricity production, but wind normally does not follow the typical demand profile. As generation flexibility is limited due to technical restrictions, and in absence of large energy storages, the other side of the equilibrium generation-demand has to react. Demand side management measures intend to adapt the demand profile to the situation in the system.
收起
摘要 :
This paper proposes a methodology for overhead line ampacity forecasting that enables empirical probabilistic forecasts to be made up to one day ahead, which is useful for grid scheduling and operation. The proposed method is base...
展开
This paper proposes a methodology for overhead line ampacity forecasting that enables empirical probabilistic forecasts to be made up to one day ahead, which is useful for grid scheduling and operation. The proposed method is based on the statistical adaptation of weather forecasts to the line-span scale and aims to produce reliable forecasts that allow the selection of a low risk of overheating overhead conductors by TSOs and DSOs. Moreover, a methodology for the evaluation of probabilistic forecasts and line capacity utilization is also proposed.
收起
原文获取