Search results for "5-7"

GOLD and the fixed ratio

2012

We thank Dr Vestbo for his interest in our manuscript “Diagnosis of airway obstruction in the elderly: contribution of the SARA study” and for the opportunity to clarify some points. As mentioned in the title and aims, the intent of the paper is to offer a contribution to the open issue of identification of airway obstruction in elderly people.1 We agree with Dr Vestbo about the utility of distinguishing between the clinical and functional aspects of chronic obstructive pulmonary disease (COPD). We stress that, until the term COPD is used, diagnosis needs clinical evidence of a chronic pulmonary disease and functional evidence of airway obstruction. Given that symptoms compatible with COPD …

Gas Transport in Mixed Matrix Membranes: Two Methods for Time Lag Determination

2020

The most widely used method to measure the transport properties of dense polymeric membranes is the time lag method in a constant volume/pressure increase instrument. Although simple and quick, this method provides only relatively superficial, averaged data of the permeability, diffusivity, and solubility of gas or vapor species in the membrane. The present manuscript discusses a more sophisticated computational method to determine the transport properties on the basis of a fit of the entire permeation curve, including the transient period. The traditional tangent method and the fitting procedure were compared for the transport of six light gases (H2, He, O2, N2, CH4, and CO2) and ethane an…

Steady State Counterbalance Valve Modeling with the Influence of Synthetic Ester Oils Using CFD

2020

This study looks in details at the effects of synthetic esters being applied to a counterbalance valve from the perspective of a system engineer. There is limited literature on the subject of applied synthetic esters and as such limited unbiased sources for information. This creates reluctance against the use of these fluids in sectors and regions with no prior experience and knowledge of what to expect. This study expands the applied literature by investigating a commercially available valve using commercial oils, a basic synthetic ester, a fully saturated synthetic ester and a typical mineral oil type for benchmarking. The investigation is based on both computational fluid dynamics and ex…

Optimal Paths on Urban Networks Using Travelling Times Prevision

2012

We deal with an algorithm that, once origin and destination are fixed, individuates the route that permits to reach the destination in the shortest time, respecting an assigned maximal travel time, and with risks measure below a given threshold. A fluid dynamic model for road networks, according to initial car densities on roads and traffic coefficients at junctions, forecasts the future traffic evolution, giving dynamical weights to a constrained 𝐾 shortest path algorithm. Simulations are performed on a case study to test the efficiency of the proposed procedure.

Modeling and Simulation of Mobile Radio Channels

2012

Efficient High-Order Iterative Methods for Solving Nonlinear Systems and Their Application on Heat Conduction Problems

2017

[EN] For solving nonlinear systems of big size, such as those obtained by applying finite differences for approximating the solution of diffusion problem and heat conduction equations, three-step iterative methods with eighth-order local convergence are presented. The computational efficiency of the new methods is compared with those of some known ones, obtaining good conclusions, due to the particular structure of the iterative expression of the proposed methods. Numerical comparisons are made with the same existing methods, on standard nonlinear systems and a nonlinear one-dimensional heat conduction equation by transforming it in a nonlinear system by using finite differences. From these…

Efficient Computation of Multiscale Entropy over Short Biomedical Time Series Based on Linear State-Space Models

2017

The most common approach to assess the dynamical complexity of a time series across multiple temporal scales makes use of the multiscale entropy (MSE) and refined MSE (RMSE) measures. In spite of their popularity, MSE and RMSE lack an analytical framework allowing their calculation for known dynamic processes and cannot be reliably computed over short time series. To overcome these limitations, we propose a method to assess RMSE for autoregressive (AR) stochastic processes. The method makes use of linear state-space (SS) models to provide the multiscale parametric representation of an AR process observed at different time scales and exploits the SS parameters to quantify analytically the co…

Studying the evolution of neural activation patterns during training of feed-forward ReLU networks

2021

The ability of deep neural networks to form powerful emergent representations of complex statistical patterns in data is as remarkable as imperfectly understood. For deep ReLU networks, these are encoded in the mixed discrete–continuous structure of linear weight matrices and non-linear binary activations. Our article develops a new technique for instrumenting such networks to efficiently record activation statistics, such as information content (entropy) and similarity of patterns, in real-world training runs. We then study the evolution of activation patterns during training for networks of different architecture using different training and initialization strategies. As a result, we see …

On Constructing Persistent Identifiers with Persistent Resolution Targets

2016

Persistent Identifiers (PID) are the foundation referencing digital assets in scientific publications, books, and digital repositories. In its realization, PIDs contain metadata and resolving targets in form of URLs that point to data sets located on the network. In contrast to PIDs, the target URLs are typically changing over time; thus, PIDs need continuous maintenance -- an effort that is increasing tremendously with the advancement of e-Science and the advent of the Internet-of-Things (IoT). Nowadays, billions of sensors and data sets are subject of PID assignment. This paper presents a new approach of embedding location independent targets into PIDs that allows the creation of maintena…

From Focused Thought to Reveries: A Memory System for a Conscious Robot

2018

© 2018 Balkenius, Tjøstheim, Johansson and Gärdenfors. We introduce a memory model for robots that can account for many aspects of an inner world, ranging from object permanence, episodic memory, and planning to imagination and reveries. It is modeled after neurophysiological data and includes parts of the cerebral cortex together with models of arousal systems that are relevant for consciousness. The three central components are an identification network, a localization network, and a working memory network. Attention serves as the interface between the inner and the external world. It directs the flow of information from sensory organs to memory, as well as controlling top-down influences…