Search results for "Grid"
showing 10 items of 792 documents
Increasing GP Computing Power for Free via Desktop GRID Computing and Virtualization
2009
This paper presents how it is possible to increase the Genetic Programming (GP) Computing Power (CP) for free, via Volunteer Computing (VC), using the well known framework BOINC plus a new ``virtualization'' layer which adds all the benefits from the virtualization paradigm. Two different experiments, employing a standard GP tool and a complex GP system, are performed --with distributed PCs over several cities-- to show the free achieved CP by means of VC, without the necessity of modifying or adapting the original GP source code. The methodology can be easily extended to Evolutionary Algorithms (EAs).
Kropp i bevegelse i bildeboka : Känner du Pippi Långstrump?
2011
In Astrid Lindgren’s authorship, there are many bodies in motion, and one of her most movable and energetic characters is Pippi Longstocking. In the illustrated novels about Pippi (Lindgren and Nyman 1945, 1946, and 1948) there are relatively few pictures, and as a result, Lindgren’s words carry most of the story. In the novels, her words have a greater functional load (Kress 2003, 46 ) than Nyman’s pictures. Naturally then, the words convey most of the information about Pippi and the other characters’ movements. But how does the portrayal of bodies in motion change when Pippi is portrayed in picturebooks where the pictures have a lot more space, ie, a greater functi…
Automatic multi-objective optimization of parameters for hardware and code optimizations
2011
Recent computer architectures can be configured in lots of different ways. To explore this huge design space, system simulators are typically used. As performance is no longer the only decisive factor but also e.g. power usage or the resource usage of the system it became very hard for designers to select optimal configurations. In this article we use a multi-objective design space exploration tool called FADSE to explore the vast design space of the Grid Alu Processor (GAP) and its post-link optimizer called GAPtimize. We improved FADSE with techniques to make it more robust against failures and to speed up evaluations through parallel processing. For the GAP, we present an approximation o…
Modeling and Experimental Validation of a Voltage-Controlled Split-Pi Converter Interfacing a High-Voltage ESS with a DC Microgrid
2023
The Split-pi converter can suitably interface an energy storage system (ESS) with a DC microgrid when galvanic isolation is not needed. Usually, the ESS voltage is lower than the grid-side voltage. However, limitations in terms of the ESS current make the use of a high-voltage ESS unavoidable when high power levels are required. In such cases, the ESS voltage can be higher than the microgrid voltage, especially with low microgrid voltages such as 48 V. Despite its bidirectionality and symmetry, the Split-pi exhibits a completely different dynamic behavior if its input and output ports are exchanged. Thus, the present work aims to model the Split-pi converter operating with an ESS voltage hi…
Review of photovoltaic status in a European (EU) perspective
2011
In the EU continent, a generation cost around 0.15€/kWh has been achieved [1]. Around the world, there is a mission to stimulate this green source of energy and it is believed that by 2030, PV will be able to deliver around 9 % of the world's electricity demands. According to an International Energy Agency (IEA) report [2], it is expected that PV will accomplish grid parity in at least 10% of the world by 2020. There was a significant 60 % annual growth in the grid connected PV systems in the span of 2004–2009 [3]. The present article will bring out the status & review of PV technology and the details of PV system standards as suggested by IEA. In the present paper, the main attention has b…
Voltage Profile Improvement for Soc Son's Low-Voltage Grid with High Penetration of PV Systems by Optimizing the Location of SVC Devices
2018
This paper presents a method that is applied to optimize the placement of Static VAR compensators in a real low-voltage grid in the Vietnamese territory. In this way, the voltage profile of the distribution grid turns to be improved. A heuristic method, the Binary Particle Swarm Optimization, is used to find a solution to this problem within the Matlab environment. A case study that considers a high penetration of rooftop PV systems in a branch of Soc Son distribution grid is implemented to show the efficiency of the optimization method for this specific application.
Storage to Avoid Congestion and Release Solar Power for Vietnam Power System: The Case Studies of a High Voltage Transmission Network in Ninh-Thuan P…
2023
The energy transition is taking place in a diverse manner around the world, and the achievement of clean energy goals could follow very different pathways. However, two recent crises of Covid-19 and Ukraine hit all markets, especially the energy market, thus influencing strongly the energy transition in most countries including Southeast Asian countries. Southeast Asian countries are now playing a prominent role in the supply chain of clean energy sources, with good examples of different renewable energy growths in a very constrained environment of resources. One of these drivers is that the proper Feed-In Tariffs (FIT) mechanism has laid the foundation for the rapid development of renewabl…
A geostatistical approach for dynamic life tables: The effect of mortality on remaining lifetime and annuities
2010
Dynamic life tables arise as an alternative to the standard (static) life table, with the aim of incorporating the evolution of mortality over time. The parametric model introduced by Lee and Carter in 1992 for projected mortality rates in the US is one of the most outstanding and has been used a great deal since then. Different versions of the model have been developed but all of them, together with other parametric models, consider the observed mortality rates as independent observations. This is a difficult hypothesis to justify when looking at the graph of the residuals obtained with any of these methods. Methods of adjustment and prediction based on geostatistical techniques which expl…
Multicanonical Monte Carlo simulations
1998
Canonical Monte Carlo simulations of disordered systems like spin glasses and systems undergoing first-order phase transitions are severely hampered by rare event states which lead to exponentially diverging autocorrelation times with increasing system size and hence to exponentially large statistical errors. One possibility to overcome this problem is the multicanonical reweighting method. Using standard local update algorithms it could be demonstrated that the dependence of autocorrelation times on the system size V is well described by a less divergent power law, τ∝Vα, with 1<α<3, depending on the system. After a brief review of the basic ideas, combinations of multicanonical reweighting…
Robust Mean Field Games
2015
Recently there has been renewed interest in large-scale games in several research disciplines, with diverse application domains as in the smart grid, cloud computing, financial markets, biochemical reaction networks, transportation science, and molecular biology. Prior works have provided rich mathematical foundations and equilibrium concepts but relatively little in terms of robustness in the presence of uncertainties. In this paper, we study mean field games with uncertainty in both states and payoffs. We consider a population of players with individual states driven by a standard Brownian motion and a disturbance term. The contribution is threefold: First, we establish a mean field syste…