Timescale effect estimation in time-series studies of air pollution and health: A Singular Spectrum Analysis approach

A wealth of epidemiological data suggests an association between mortality/morbidity from pulmonary and cardiovascular adverse events and air pollution, but uncertainty remains as to the extent implied by those associations although the abundance of the data. In this paper we describe an SSA (Singular Spectrum Analysis) based approach in order to decompose the time-series of particulate matter concentration into a set of exposure variables, each one representing a different timescale. We implement our methodology to investigate both acute and long-term effects of $PM_{10}$ exposure on morbidity from respiratory causes within the urban area of Bari, Italy.Comment: Published in at http://dx.doi.org/10.1214/07-EJS123 the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org

Simulating Cellular Communications in Vehicular Networks: Making SimuLTE Interoperable with Veins

The evolution of cellular technologies toward 5G progressively enables efficient and ubiquitous communications in an increasing number of fields. Among these, vehicular networks are being considered as one of the most promising and challenging applications, requiring support for communications in high-speed mobility and delay-constrained information exchange in proximity. In this context, simulation frameworks under the OMNeT++ umbrella are already available: SimuLTE and Veins for cellular and vehicular systems, respectively. In this paper, we describe the modifications that make SimuLTE interoperable with Veins and INET, which leverage the OMNeT++ paradigm, and allow us to achieve our goal without any modification to either of the latter two. We discuss the limitations of the previous solution, namely VeinsLTE, which integrates all three in a single framework, thus preventing independent evolution and upgrades of each building block.Comment: Published in: A. Foerster, A. Udugama, A. Koensgen, A. Virdis, M. Kirsche (Eds.), Proc. of the 4th OMNeT++ Community Summit, University of Bremen - Germany - September 7-8, 201

Effectiveness of cognitive and physical training in slowing progression to dementia: a clinical and experimental study. Focus on relationship with cardiovascular fitness

Physical activity is beneficial to vascular health; on the other hand, vascular damage is associated with cognitive impairment. Both physical activity and a cognitively stimulating environment are known to delay the onset of dementia. The Train The Brain study evaluated the effectiveness of a comprehensive program of physical training and mental activity in delaying cognitive decline in elderly people with initial cognitive impairment, at the same time investigating the relationship between physical, vascular, neurological, and cognitive fitness. Elders age 65-89 with were recruited with the help of family physicians and territorial services. All participants underwent a neurological and cardiologic evaluation. Carotid-femoral pulse wave velocity and carotid pressure were measured with the SphygmoCor system (AtCor, Australia). Longitudinal ultrasound scans of the common carotid were performed and 10-second video clips were recorded to be analysed offline through the Cardiovascular Suite software (Quipu srl, Italy), with the computation of diameter, intima-media thickness, wall cross-sectional area, distensibility coefficient, and elastic modulus. The latter software was used also to measure endothelial function through flow mediated dilation (FMD) of the brachial artery. Subjects classified as mild cognitive impairment at the neurological examination were randomized either to standard care, or a 7-month program of physical training and environmental stimulation (lectures, games, music, social activities) three hours a week. The evaluation was then repeated. Data were obtained for 54 patients who underwent training and 36 controls. The intervention was successful in improving cognitive function as measured through the ADAS-Cog score: 11.95 (3.86) to 13.00 (4.73) for no training, 14.32 (4.27) to 12.85 (4.03) for training, time x treatment p<0.001. Pulse wave velocity showed no significant effect (p=0.5). FMD improved with intervention (no training: 3.20 (2.03) to 2.50 (1.77) %; training: from 2.82 (2.19) to 3.42 (1.82); p=0.014). All selected carotid parameters were influenced by the combination of time and treatment, in a diverging trend, at a statistically significant level, with intervention determining less dilated, less thick and less stiff vessels. None of the parameters measured analysing the vessels showed a correlation The proposed 7-months program improved cognitive function in elders with initial cognitive impairment. There was a significant difference in behaviour in time of the two groups as for endothelial function and carotid enlargement, wall thickening and arterial stiffening. The intervention seems to oppose the typical harmful effects of aging on vessels; at the same time, the positive effects on cognition and vascular health do not appear as directly correlated

The Relationship of Skin Conductance to Behavior in a Vigilance Task

The present study is an attempt to measure the correlation between vigilance , as indicated by signal detection, and the galvanic skin response (GSR). The following four dependent variables were measured: (a) Galvanic skin response (continuously recorded, although discrete values were later selected for measurement); (b) ommission errors (where S fails to detect a signal which has occurred); (c) commission errors (or false detections , where S detects a signal which has not in fact occurred); and (d) reaction times to signals. The major purpose of the present study was, in part, to replicate the Ross, Dardano, and Hackman study utilizing more sophisticated equipment and larger number of subjects and, by taking continuous GSR measurements, to more exhaustively test major hypothesis that a relationship exists between the galvanic skin response and vigilance

Nancy: An efficient parallel Network Calculus library

This paper describes Nancy, a Network Calculus (NC) library that allows users to perform complex min-plus and max-plus algebra operations efficiently. To the best of our knowledge, Nancy is the only open-source library that implements operations working on arbitrary piecewise affine functions, as well as to implement some of them (e.g. sub-additive closure and function composition). Nancy allows researchers to compute NC results using a straightforward syntax, which matches the algebraic one. Moreover, it is designed having computational efficiency in mind: it exploits optimizations of data structures, it uses inheritance to allow for faster algorithms when they are available (e.g., for specific subclasses of functions), and it is natively parallel, thus reaping the benefit of multicore hardware. This makes it usable to solve NC problems which were previously considered beyond the realm of tractable

A comprehensive simulation analysis of LTE Discontinuous Reception (DRX)

In an LTE cell, Discontinuous Reception (DRX) allows the central base station to configure User Equipments for periodic wake/sleep cycles, so as to save energy. DRX operations depend on several parameters, which can be tuned to achieve optimal performance with different traffic profiles (i.e., CBR vs. bursty, periodic vs. sporadic, etc.). This work investigates how to configure these parameters and explores the trade-off between power saving, on one side, and per-user QoS, on the other. Unlike previous work, chiefly based on analytical models neglecting key aspects of LTE, our evaluation is carried out via simulation. We use a fully-fledged packet simulator, which includes models of all the protocol stack, the applications and the relevant QoS metrics, and employ factorial analysis to assess the impact of the many simulation factors in a statistically rigorous way. This allows us to analyze a wider spectrum of scenarios, assessing the interplay of the LTE mechanisms and DRX, and to derive configuration guidelines

System-level analysis of the tradeoffs between power saving and capacity/QoS with DRX in LTE

In an LTE cell, Discontinuous Reception (DRX) allows the central base station to configure User Equipment for periodic wake/sleep cycles, so as to save energy. Several parameters are associated to DRX operations, thus allowing for optimal performance with different traffic profiles (i.e., CBR-like, bursty, periodic arrivals of variable-sized packets, etc.). This work investigates how to configure these parameters and explores the tradeoff between power saving, on one side, and per-user QoS and cell capacity, on the other. Unlike previous work, mostly based on analytical models neglecting key aspects of LTE, our evaluation is carried out using a fully-fledged packet simulator. This allows us to discover previously unknown relationships and to propose configuration guidelines for operators

Public sector ICT management strategy and its impact on e-government: a case study

This paper explores the relationship between public sector information and communications technology (ICT) management strategies and electronic government (e-Gov) initiatives. We use an adaptation of the technology enactment framework to explore various technological, organisational, and institutional factors that play a role in the development of ICT management strategies in a public agency. Using the case study of a city (anonymised and referred to in this paper as the ‘City’) in the U.S. state of Connecticut, we examine how these factors in turn help determine the city’s e-Gov initiatives. Our findings show that the bureaucratic structure and culture of the public agency play a key role in the type of ICT strategy adopted in the city and that this has important repercussions for the outcome of its e-Gov programme

Singular Spectrum Analysis: a new decomposition technique applied to environmental systems

EnIn the last few years Singular Spectrum Analysis (SSA), a powerful tool in time series In the last few years Singular Spectrum Analysis (SSA), a powerful tool in time series reconstruction of components may based on the functional clustering algorithm introduced in Bilancia and Stea (2008). We report an example concerning an application in the environmental health field

Exact Worst-case Delay in FIFO-multiplexing Feed-forward Networks

In this paper, we compute the actual worst-case end-to-end delay for a flow in a feed-forward network of first-in–first-out (FIFO)-multiplexing service curve nodes, where flows are shaped by piecewise-affine concave arrival curves, and service curves are piecewise affine and convex. We show that the worst-case delay problem can be formulated as a mixed integer linear programming problem, whose size grows exponentially with the number of nodes involved. Furthermore, we present approximate solution schemes to find upper and lower delay bounds on the worst-case delay. Both only require to solve just one linear programming problem and yield bounds that are generally more accurate than those found in the previous work, which are computed under more restrictive assumptions