Search results for "Storage"
showing 10 items of 1239 documents
Load match optimisation of a residential building case study: A cross-entropy based electricity storage sizing algorithm
2015
Abstract The EU EPBD recast regulation marked the application of the net zero energy building (Net ZEB) concept in all fields of building construction in Europe as a building able to generate as much energy as it consumes over a selected time frame. A more detailed insight is however needed, as even if a building achieves a long-term energy balance between energy generated and consumed, smaller time scales must also be considered. For example, from the utility’s point of view, if a Net ZEB is a heavy consumer in the winter, it will appear to be quite similar to a conventional building, requiring the use of additional generation. The increase in the generation-load match means reducing the s…
A NEW REPRESENTATION OF ENERGY STORAGE SYSTEMS OPERATION USING FOURIER THEORY IN OPTIMAL SMART GRIDS MANAGEMENT
2012
This paper investigates the possibility to use a new modeling of Energy Storage Systems based on zero integral functions. Such functions represent the course of the energy level stored in batteries during the solution of optimal management problems in smart-grids. Storage devices, such as all the other components that are required to meet an integral capacity constraint along the dispatch time, must show the same State of Charge at the start and at the end of the timeframe considered for operation. In this paper, a set of sinusoidal functions have been used for the synthesis of the charge and discharge course of energy Storage Systems. Such representation allows to eliminate the difficult c…
Modelling energy storage systems using Fourier analysis: An application for smart grids optimal management
2014
In this paper, a new and efficient model for variables representation, named F-coding, in optimal power dispatch problems for smart electrical distribution grids is proposed. In particular, an application devoted to optimal energy dispatch of Distributed Energy Resources including ideal storage devices is here considered. Electrical energy storage systems, such as any other component that must meet an integral capacity constraint in optimal dispatch problems, have to show the same energy level at the beginning and at the end of the considered timeframe for operation. The use of zero-integral functions, such as sinusoidal functions, for the synthesis of the charge and discharge course of bat…
Methods cooperation for multiresolution motion estimation
2002
For a medical application, we are interested in an estimation of optical flow on a patient's face, particularly around the eyes. Among the methods of optical flow estimation, gradient estimation and block matching are the main methods. However, the gradient-based approach can only be applied for small displacements (one or two pixels). Gener- ally, the process of block matching leads to good results only if the searching strategy is judiciously selected. Our approach is based on a Markov random field model, combined with an algorithm of block match- ing in a multiresolution scheme. The multiresolution approach allows de- tection of a large range of speeds. The large displacements are detect…
Synaptic Scaling Enables Dynamically Distinct Short- and Long-Term Memory Formation
2013
Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling – a slow process usually associated with the maintenance of activity homeostasis – combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The inter…
Towards Dynamic Scripted pNFS Layouts
2012
Today's network file systems consist of a variety of complex subprotocols and backend storage classes. The data is typically spread over multiple data servers to achieve higher levels of performance and reliability. A metadata server is responsible for creating the mapping of a file to these data servers. It is hard to map application specific access patterns to storage system specific features, which can result in a degraded IO performance. We present an NFSv4.1/pNFS protocol extension that integrates the client's ability to provide hints and I/O advices to metadata servers. We define multiple storage classes and allow the client to choose which type of storage fits best for its desired ac…
ADA-FS—Advanced Data Placement via Ad hoc File Systems at Extreme Scales
2020
Today’s High-Performance Computing (HPC) environments increasingly have to manage relatively new access patterns (e.g., large numbers of metadata operations) which general-purpose parallel file systems (PFS) were not optimized for. Burst-buffer file systems aim to solve that challenge by spanning an ad hoc file system across node-local flash storage at compute nodes to relief the PFS from such access patterns. However, existing burst-buffer file systems still support many of the traditional file system features, which are often not required in HPC applications, at the cost of file system performance.
One Phase Commit: A Low Overhead Atomic Commitment Protocol for Scalable Metadata Services
2012
As the number of client machines in high end computing clusters increases, the file system cannot keep up with the resulting volume of requests, using a centralized metadata server. This problem will be even more prominent with the advent of the exascale computing age. In this context, the centralized metadata server represents a bottleneck for the scaling of the file system performance as well as a single point of failure. To overcome this problem, file systems are evolving from centralized metadata services to distributed metadata services. The metadata distribution raises a number of additional problems that must be taken into account. In this paper we will focus on the problem of managi…
The Blockchain in Microgrids for Transacting Energy and Attributing Losses
2017
In recent years novel models for energy distribu- tion appeared and islanded microgrids quest for new ways to exchange energy between consumers and producers without the need of central authorities. The blockchain mechanism has emerged as a distributed solution for recording energy transactions in power systems. The blockchain has been used to permit users bartering and selling energy and to keep track of such exchanges without exposing them to tampering. In this work, we consider a novel application of the blockchain in islanded microgrids that includes also annotating energy losses caused by energy transactions, in order to have a more realistic matching between the physical status of the…
Effect of refrigerated storage on microbiological, chemical and sensory characteristics of a ewes’ raw milk stretched cheese
2017
This study aimed to describe the effects of refrigerated storage up to 180 days on microbiological, chemical, physical, and sensory characteristics of a PDO ewes’ raw milk stretched cheese. To this aim, a total of 224 cheeses were manufactured in four consecutive production weeks, and series of 32 of them were examined before packaging and after 15, 30, 60, 90, 120, and 180 d of storage at 4 ± 2 °C in the dark, respectively. Lactic acid bacteria cocci displayed the highest levels (7.8 Log CFU*g−1) during early storage and decreased progressively over time (7.4 Log CFU*g−1), while the opposite trend was observed for lactic acid bacteria rods (from 6.5 to 7.3 Log CFU*g−1). TMC and enterocci s…