Search results for "working"

NVMM-Oriented Hierarchical Persistent Client Caching for Lustre

2021

In high-performance computing (HPC), data and metadata are stored on special server nodes and client applications access the servers’ data and metadata through a network, which induces network latencies and resource contention. These server nodes are typically equipped with (slow) magnetic disks, while the client nodes store temporary data on fast SSDs or even on non-volatile main memory (NVMM). Therefore, the full potential of parallel file systems can only be reached if fast client side storage devices are included into the overall storage architecture. In this article, we propose an NVMM-based hierarchical persistent client cache for the Lustre file system (NVMM-LPCC for short). NVMM-LPC…

Online topology estimation for vector autoregressive processes in data networks

2017

An important problem in data sciences pertains to inferring causal interactions among a collection of time series. Upon modeling these as a vector autoregressive (VAR) process, this paper deals with estimating the model parameters to identify the underlying causality graph. To exploit the sparse connectivity of causality graphs, the proposed estimators minimize a group-Lasso regularized functional. To cope with real-time applications, big data setups, and possibly time-varying topologies, two online algorithms are presented to recover the sparse coefficients when observations are received sequentially. The proposed algorithms are inspired by the classic recursive least squares (RLS) algorit…

Graph recursive least squares filter for topology inference in causal data processes

2017

In this paper, we introduce the concept of recursive least squares graph filters for online topology inference in data networks that are modelled as Causal Graph Processes (CGP). A Causal Graph Process (CGP) is an auto regressive process in the time series associated to different variables, and whose coefficients are the so-called graph filters, which are matrix polynomials with different orders of the graph adjacency matrix. Given the time series of data at different variables, the goal is to estimate these graph filters, hence the associated underlying adjacency matrix. Previously proposed algorithms have focused on a batch approach, assuming implicitly stationarity of the CGP. We propose…

Guaranteed access mode for downlink traffic over IEEE 802.11 WLANs

2011

IEEE 802.11 networks present an unfairness problem between the downlink and uplink traffic, using the default settings of the Enhanced Distributed Channel Access (EDCA). In order to reduce this unfairness, the Access Point (AP) can adapt the standard parameters, but this is not enough. In this paper, we propose simple and efficient solutions, which are implemented at the AP, thus they are standard compatible and no modifications to the current hardware and protocol stacks are needed. These solutions aim at providing guaranteed access to the downlink traffic when the AP perceives the unfairness problem. Our simulation results show a reduction in the unfairness and an enhancement in network p…

Effects of complex movements on the brain as a result of increased decision-making

2019

Non-linearity is considered to be an essential property of complex systems. The associated high sensitivity of the result on the constraints leads to fundamental problems of a system description based on variables selected in the reductionist tradition. The attempt to compensate the problems by averaging data leads to the neglect of the individual and the moment. However, both is of enormous importance for effective therapy, training, and learning. The theory of differential learning suggests an alternative approach to dealing with these problems. With constantly changing complex whole-body movements, extensive decisions are demanded from the learner, which lead to brain states through an o…

Modelling the regenerative niche: a major challenge in biomaterials research

2015

By definition, biomaterials are developed for clinical application. In the field of regenerative medicine their principal function is to play a significant, and, if possible, an instructive role in tissue healing. In the last analysis the latter involves targeting the 'regenerative niche'. The present paper will address the problem of simulating this niche in the laboratory and adopts a life science approach involving the harnessing of heterotypic cellular communication to achieve this, that is, the ability of cells of different types to mutually influence cellular functions. Thus, co-culture systems using human cells are the methodological focus and will concern four exemplary fields of re…

AN ATTEMPT TO INVESTIGATE THE IMPACT OF SELECTED INFRASTRUCTURE INVESTMENTS ON THE POTENTIAL DEVELOPMENT OF THE BIGGEST EUROPEAN CITIES. APPLICATION …

2019

Przedmiotem niniejszego artykułu jest symulacyjne badanie dyfuzji zmian gospodarczych, oparte na ugruntowanym modelu pośrednich możliwości. Użyty algorytm  umożliwił detekcję makroregionów europejskich, w których istnieje wyraźnie podwyższony potencjał rozwoju wielobranżowych klastrów gospodarczych. Eksperymenty symulacyjne wykonano w dwóch seriach: dla prognozy wpływu działania Centralnego Portu Komunikacyjnego oraz dla działania CPK łącznie z budowaną jednocześnie Via Carpatia (czyli tzw. “Nowym Szlakiem Bursztynowym”).  W niniejszym artykule staraliśmy się odpowiedzieć na pytanie: które rejony Europy najwięcej zyskają działaniu Centralnego Portu Komunikacyjnego?
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Raising the fatigue durability curves in case of the rehabilitation welding techniques

2018

Prevention of occupational injuries moral hazard and complex agency relationship

2001

This paper exploits the results of agency theory with the aim of contributing a new viewpoint and a form for analysis of the current functioning of the occupational injury and disease section of the Social Security system in its mission of providing incentives for prevention. After outlining the organization and specific features of insurance against occupational risks, an initial level of analysis highlights the presence of moral hazard in relations between insurer and company and between company and employee. A second level of analysis and resort to complex agency relationship models, multitask model and third-party model, is necessary to take into account the consequences for occupationa…

Introduzione alle relazioni finali dei gruppi

2016

Sono introdotte e commentate le relazioni finali dei gruppi di studio che si sono svolti durante la Summer School organizzata dalla Siped a Enna nel luglio del 2015. I diversi contributi sono collocati all’interno del dibattito scientifico in corso per ognuno dei temi affrontati nei lavori svolti durante la manifestazione sulle tendenze della ricerca pedagogica in Italia. The final reports of the study groups that worked during the Summer School organized by SIPED in Enna in July 2015 are here introduced and discussed. The various contributions are placed within the current scientific debate for each one of the themes dealing with during the demonstration on pedagogical research trends in I…