Search results for " synchronization"
showing 10 items of 75 documents
Evidence of unbalanced regulatory mechanism of heart rate and systolic pressure after acute myocardial infarction
2002
The interactions between systolic arterial pressure (SAP) and R-R interval (RR) fluctuations after acute myocardial infarction (AMI) were investigated by measures of synchronization separating the feedback from the feedforward control and capturing both linear and nonlinear contributions. The causal synchronization, evaluating the ability of RR to predict SAP (χs/t) or vice versa (χt/s), and the global synchronization (χ) were estimated at rest and after head-up tilt in 35 post-AMI patients, 20 young and 12 old. Significance and nonlinearity of the coupling were assessed by surrogate data analysis. Tilting increased the number of young subjects in which RR-SAP link was significant (from 17…
Sectoral Business Cycle Synchronization in the European Union
2007
This paper analyses sectoral business cycle synchronization in an enlarged European Union using annual data for the period 1980-2005. In particular, we try to identify which sector for each country is driving the aggregate output business cycle synchronization. Overall, the sectors that provide the most relevant contribution are Industry, Building and Construction, and Agriculture, Fishery and Forestry. In contrast, the Services sector, the largest one in terms of valued added share, shows a relative low business cycle synchronization and volatility, implying that it contributes only marginally to the aggregate output business cycle synchronization.
Estimation of Granger causality through Artificial Neural Networks: applications to physiological systems and chaotic electronic oscillators
2021
One of the most challenging problems in the study of complex dynamical systems is to find the statistical interdependencies among the system components. Granger causality (GC) represents one of the most employed approaches, based on modeling the system dynamics with a linear vector autoregressive (VAR) model and on evaluating the information flow between two processes in terms of prediction error variances. In its most advanced setting, GC analysis is performed through a state-space (SS) representation of the VAR model that allows to compute both conditional and unconditional forms of GC by solving only one regression problem. While this problem is typically solved through Ordinary Least Sq…
Fiscal Adjustment and Business Cycle Synchronization
2013
Using a panel of annual data for 20 countries we show that synchronized fiscal consolidation (stimulus) programmes in different countries make their business cycles more closely linked, especially in the case of fiscal adjustments lasting 2 or 3 years. We also find: (i) little evidence of decoupling when an inflation targeting regime is unilaterally adopted; (ii) an increase in business cycle synchronization when countries fix their exchange rates and become members of a monetary union; (iii) a positive effect of bilateral trade on the synchronization of business cycles.
Design and validation of a wireless Body Sensor Network for integrated EEG and HD-sEMG acquisitions
2022
Sensorimotor integration is the process through which the human brain plans the motor program execution according to external sources. Within this context, corticomuscular and corticokinematic coherence analyses are common methods to investigate the mechanism underlying the central control of muscle activation. This requires the synchronous acquisition of several physiological signals, including EEG and sEMG. Nevertheless, physical constraints of the current, mostly wired, technologies limit their application in dynamic and naturalistic contexts. In fact, although many efforts were made in the development of biomedical instrumentation for EEG and High Density-surface EMG (HD-sEMG) signal ac…
Business Cycles Synchronization in the EMU
2008
This article asks whether the business cycles of the EU countries have become more or less synchronized after the introduction of the euro. Our findings show that all countries in our EU sample are better synchronized with the EMU-wide economy in the post-EMU period than they were before the euro. We also show that this increase in synchronization is present in all components of aggregate demand, as well as two supply-side variables, but it is more pronounced in the trade components (imports and, particularly, exports). It is also shown that the increase in trade within the EMU area is at least partly responsible for the increase in cyclical synchronization.
Stability of charge-pump phase-locked loops : the hold-in and pull-in ranges
2020
The problem of design and analysis of synchronization control circuits is a challenging task for many applications: satellite navigation, digital communication, wireless networks, and others. In this article the Charge-Pump Phase-Locked Loop (CP-PLL) electronic circuit, which is used for frequency synthesis and clock generation in computer architectures, is studied. Analysis of CP-PLL is not trivial: full mathematical model, rigorous definitions, and analysis still remain open issues in many respects. This article is devoted to development of a mathematical model, taking into account engineering aspects of the circuit, interpretation of core engineering problems, definition in relation to m…
Evaluation of the Impact of Multipath Data Dispersion for Anonymous TCP Connections
2007
Despite recent research efforts, wireless ad hoc networking technology remains especially prone to security attacks. In this work our contribution focuses on determining the optimal trade-off between traffic dispersion and TCP performance to reduce the chances of successful eavesdropping, while maintaining acceptable levels of throughput. For our experiments we propose a multipath-enhanced version of DSR, and we compare Tahoe, Reno and Sack TCP variants. Results show that multipath traffic dispersion impact on TCP throughput is bounded to a maximum of 25-35%, and that there is only a minimal dependence on the number of routes used, the number of consecutive packets sent on each route, the r…
Adaptive Low Priority Packet Marking for Better TCP Performance
2003
This paper proposes a packet marking scheme for TCP traffic. Unlike previous literature work, in our scheme the majority of TCP packets are transmitted as high priority. The role of a low priority packet appears that of a probe, whose goal is to early discover network congestion conditions. Low priority packets are marked according to an adaptive marking algorithm. Numerical results show that our scheme provides improved throughput/delay performance.
TCP Performance in Mobile Ad hoc Networks
2013
International audience; In this paper, we present a survey of TCP (Transmission Control Protocol) protocol for better performance in the MANET (Mobile Ad Hoc Network). After a short presentation of the main features of TCP, we give the most important problems from which TCP suffer in MANET. We present after that some approaches proposed in the literature in order to improve its performance. Our paper contains also a performance evaluation of TCP NewReno and TCP Vegas transport protocols under AODV and DSR routing protocols. The simulations are conducted under varying conditions of number of TCP connections, number of nodes and mobility.