Search results for "Tribute"
showing 10 items of 1455 documents
Analyzing the Energy Efficiency of the Memory Subsystem in Multicore Processors
2014
In this paper we analyze the energy overhead incurred when operating with data stored in different levels of the memory subsystem (cache levels and DDR chips) of current multicore architectures. Our approach builds upon servet, a portable framework for the memory characterization of multicore processors, extending this suite with a power-related test that, when applied to a platform equipped with a power measurement mechanism, provides information on the efficiency of memory energy usage. As additional contributions, i) we provide a complete experimental study of the impact that the CPU performance states (also known as P-states) exert on the memory energy efficiency of a collection of rece…
The soluble loop BC region guides, but not dictates, the assembly of the transmembrane cytochrome b6
2017
Studying folding and assembly of naturally occurring α-helical transmembrane proteins can inspire the design of membrane proteins with defined functions. Thus far, most studies have focused on the role of membrane-integrated protein regions. However, to fully understand folding pathways and stabilization of α–helical membrane proteins, it is vital to also include the role of soluble loops. We have analyzed the impact of interhelical loops on folding, assembly and stability of the heme-containing four-helix bundle transmembrane protein cytochrome b6 that is involved in charge transfer across biomembranes. Cytochrome b6 consists of two transmembrane helical hairpins that sandwich two heme mol…
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…
Using On-Demand File Systems in HPC Environments
2019
In modern HPC systems, parallel (distributed) file systems are used to allow fast access from and to the storage infrastructure. However, I/O performance in large-scale HPC systems has failed to keep up with the increase in computational power. As a result, the I/O subsystem which also has to cope with a large number of demanding metadata operations is often the bottleneck of the entire HPC system. In some cases, even a single bad behaving application can be held responsible for slowing down the entire HPC system, disrupting other applications that use the same I/O subsystem. These kinds of situations are likely to become more frequent in the future with larger and more powerful HPC systems…
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 MoSGrid Science Gateway – A Complete Solution for Molecular Simulations
2014
The MoSGrid portal offers an approach to carry out high-quality molecular simulations on distributed compute infrastructures to scientists with all kinds of background and experience levels. A user-friendly Web interface guarantees the ease-of-use of modern chemical simulation applications well established in the field. The usage of well-defined workflows annotated with metadata largely improves the reproducibility of simulations in the sense of good lab practice. The MoSGrid science gateway supports applications in the domains quantum chemistry (QC), molecular dynamics (MD), and docking. This paper presents the open-source MoSGrid architecture as well as lessons learned from its design.
Criteri e metodi per l'ottimizzazione di sistemi di poligenerazione di piccola e media taglia - Criteria and methodologies for the optimization of sm…
2011
L'Unione Europea ha individuato nella produzione combinata di energia elettrica e calore una delle tecnologie ad alta efficienza di maggior interesse, fissando per il 2010 il target del 18% della produzione elettrica totale dell'Unione da sistemi cogenerativi (COM/97/0514). Dati recenti rivelano la non attualità di tale target (al 2005 si è raggiunto il 12% di penetrazione); rimane tuttavia evidente la volontà, esistente sia a livello comunitario che in molti Stati Membri, di perseguire la via della promozione della poligenerazione. Le ragioni di questo interesse sono evidenti: l'elevata efficienza di conversione garantita dal recupero dei cascami termici di un ciclo diretto consente, a par…
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…
A Lightweight Middleware Platform for Distributed Computing on Wireless Sensor Networks
2014
Abstract The peculiar features of Wireless Sensor Networks (WSNs) suggest to exploit the distributed computing paradigm to perform complex tasks in a collaborative manner, in order to overcome the constraints related to sensor nodes limited capabilities. In this context, we describe a lightweight middleware platform to support the development of distributed applications on WSNs. The platform provides just a minimal general-purpose software layer, while the application components, including communication and processing algorithms, as well as the exchanged data, are described symbolically, with neither preformed syntax nor strict distinction between data and code. Our approach allows for inte…
Performance Analysis of Memory Cloning Solutions in Mobile Edge Computing
2018
This paper deals with the problem of service migration in the emerging scenarios of Mobile Edge Computing. Mobile edge computing is achieved by moving the traditional cloud infrastructures, exploited by many today applications, close to the network edge in order to reduce the response times in the so called tactile-internet. However, because of user mobility, such an application architecture may pose the problem of service migration in case of handover from one server site to another. After introducing the current solutions for dealing with service migration and, in particular, the approaches based on service decomposition into multiple layers, we quantify the migration time and the service…