Fluctuations Research Papers - Academia.edu (original) (raw)

Variation in time between two successive heart beats occurring due to internal and external stimulation causes Heart Rate Variability (HRV). HRV is a tool for indirect investigation of both cardiac and autonomic system function in both... more

Variation in time between two successive heart beats occurring due to internal and external stimulation causes Heart Rate Variability (HRV). HRV is a tool for indirect investigation of both cardiac and autonomic system function in both healthy and diseased condition. It has been speculated that HRV analysis by nonlinear method might bring potentially useful prognosis information into light which will be helpful for assessment of cardiac condition. In this study, HRV from two types of data sets (normal sinus rhythm and sinus arrhythmia) are analyzed which are stored in MIT-BIH (Massachusetts Institute of Technology – Beth Israel hospital) database, an extended collection of recorded physiological signals. Then two nonlinear methods, approximate entropy (ApEn) and detrended fluctuation analysis (DFA), have been applied to analyze HRV of both Arrhythmia patients and people having normal sinus rhythm. It has been clearly shown that nonlinear parameters obtained from these two methods reflect the opposite heart condition of the two types of subjects under study, healthy and diseased, by HRV measures. Thus, value of the nonlinear parameters found in this work can be used as standard when treating suspected patients for diagnosis of Arrhythmia. Also, by measuring these nonlinear parameter values, heart condition can be understood.

Less than 116 ps overall clock skew has been achieved across the 15.02 mm/spl times/15.03 mm die by balanced clock path routing and differential clock signal distribution in the global clock tree of 300 MHz 128-bit 2-way superscalar... more

Less than 116 ps overall clock skew has been achieved across the 15.02 mm/spl times/15.03 mm die by balanced clock path routing and differential clock signal distribution in the global clock tree of 300 MHz 128-bit 2-way superscalar microprocessor. The shared clock wire configuration and clock buffer layout patterns over the whole die enhance the clock skew insensitivity to process

In this paper, we address the issue of how education affected income inequality in twentieth-century Africa. Three channels are identified through which education may affect income inequality. First, an increase in the average educational... more

In this paper, we address the issue of how education affected income inequality in twentieth-century Africa. Three channels are identified through which education may affect income inequality. First, an increase in the average educational level is correlated with an increase in average income, which, ceteris paribus, reduces inequality. Second, a reduction in educational inequality may, given a positive correlation between education level and income, reduce income inequality. Thirdly, an increase in the supply of education may decrease the price of skilled labour thus lowering income inequality. We find that in the long-run education does not affect income growth, indicating that in twentieth-century Africa it was inspiration (i.e., Total Factor Productivity [TFP]) rather than perspiration (i.e., education and physical capital) that drove economic development. Testing for the effects of the remaining two channels, we found a significant non-linear relationship between educational an...

... and small scale fading in indoor wireless communication channels. Reinaldo A. Valenzuela, Dmitry Chizhik and Jonathan Ling ... References [I] R. A. Valenzuela, 0. Landron, DL Jacobs, "Estimating Local Mean Signal Strength of... more

... and small scale fading in indoor wireless communication channels. Reinaldo A. Valenzuela, Dmitry Chizhik and Jonathan Ling ... References [I] R. A. Valenzuela, 0. Landron, DL Jacobs, "Estimating Local Mean Signal Strength of Indoor Multipath Propagation", IEEE Trans. ...

The basic theory of Markov chains has been known to mathematicians and engineers for close to 80 years, but it is only in the past decade that it has been applied explicitly to problems in speech processing. One of the major reasons why... more

The basic theory of Markov chains has been known to mathematicians and engineers for close to 80 years, but it is only in the past decade that it has been applied explicitly to problems in speech processing. One of the major reasons why speech models, based on Markov chains, have not been developed until recently was the lack of a method for optimizing the parameters of the Markov model to match observed signal patterns. Such a method was proposed in the late 1960's and was immediately applied to speech processing in several research institutions. Continued refinements in the theory and implementation of Markov modelling techniques have greatly enhanced the method, leading to a wide range of applications of these models. It is the purpose of this tutorial paper to give an introduction to the theory of Markov models, and to illustrate how they have been applied to problems in speech recognition.

We study a model of Brownian particles which are pumped with energy by means of a non-linear friction function, for which different types are discussed. A suitable expression for a non-linear, velocity-dependent friction function is... more

We study a model of Brownian particles which are pumped with energy by means of a non-linear friction function, for which different types are discussed. A suitable expression for a non-linear, velocity-dependent friction function is derived by considering an internal energy depot of the Brownian particles. In this case, the friction function describes the pumping of energy in the range of small velocities, while in the range of large velocities the known limit of dissipative friction is reached. In order to investigate the influence of additional energy supply, we discuss the velocity distribution function for different cases. Analytical solutions of the corresponding Fokker-Planck equation in 2d are presented and compared with computer simulations. Different to the case of passive Brownian motion, we find several new features of the dynamics, such as the formation of limit cycles in the four-dimensional phase-space, a large mean squared displacement which increases quadratically with the energy supply, or non-equilibrium velocity distributions with crater-like form. Further, we point to some generalizations and possible applications of the model.

This paper analyzes effects of different practice task constraints on heart rate (HR) variability during 4v4 smallsided football games. Participants were sixteen football players divided into two age groups (U13, Mean age: 12.4±0.5 yrs;... more

This paper analyzes effects of different practice task constraints on heart rate (HR) variability during 4v4 smallsided football games. Participants were sixteen football players divided into two age groups (U13, Mean age: 12.4±0.5 yrs; U15: 14.6±0.5). The task consisted of a 4v4 sub-phase without goalkeepers, on a 25x15 m field, of 15 minutes duration with an active recovery period of 6 minutes between each condition. We recorded players’ heart rates using heart rate monitors (Polar Team System, Polar Electro, Kempele, Finland) as scoring mode was manipulated (line goal: scoring by dribbling past an extended line; double goal: scoring in either of two lateral goals; and central goal: scoring only in one goal). Subsequently, %HR reserve was calculated with the Karvonen formula. We performed a time-series analysis of HR for each individual in each condition. Mean data for intra-participant variability showed that autocorrelation function was associated with more short-range dependence processes in the “line goal” condition, compared to other conditions, demonstrating that the “line goal” constraint induced more randomness in HR response. Relative to inter-individual variability, line goal constraints demonstrated lower %CV and %RMSD (U13: 9% and 19%; U15: 10% and 19%) compared with double goal (U13: 12% and 21%; U15: 12% and 21%) and central goal (U13: 14% and 24%; U15: 13% and 24%) task constraints, respectively. Results suggested that line goal constraints imposed more randomness on cardiovascular stimulation of each individual and lower inter-individual variability than double goal and central goal constraints.

Crosstalk noise is a crucial factor affecting chip performance in deep submicron technologies. Among all possible crosstalk noise sources, clock is the most common aggressor as well as victim. Crosstalk on clock nets can increase clock... more

Crosstalk noise is a crucial factor affecting chip performance in deep submicron technologies. Among all possible crosstalk noise sources, clock is the most common aggressor as well as victim. Crosstalk on clock nets can increase clock jitter, which may degrade significantly the system performance. It is therefore imperative to design clock buffers to reduce the coupling effects. In this paper, we address the crosstalk effect on clock networks. We propose an algorithm to size clock buffers for given buffered clock trees such that the induced clock jitter is minimized. Our experimental results show a significant reduction of clock jitter by sizing the clock buffers without increasing the total area of buffer.

In mobile radio systems the effects of fading can be counteracted by the use of diversity techniques either at the base station or the mobile. Since reducing fading, diversity schemes contribute to the reduction of the bit error rate that... more

In mobile radio systems the effects of fading can be counteracted by the use of diversity techniques either at the base station or the mobile. Since reducing fading, diversity schemes contribute to the reduction of the bit error rate that degrades the performance of any modulation scheme. This paper attempts to determine the performance of a typical TETRA system, without

The high variability of solar irradiance, originated by moving clouds, causes fluctuations in Photovoltaic (PV) power generation, and can negatively impact the grid stability. For this reason, grid codes have incorporated ramp-rate... more

The high variability of solar irradiance, originated by moving clouds, causes fluctuations in Photovoltaic (PV) power generation, and can negatively impact the grid stability. For this reason, grid codes have incorporated ramp-rate limitations for the injected PV power. Energy Storage Systems (ESS) coordinated by ramp-rate (RR) control algorithms are often applied for mitigating these power fluctuations to the grid. These algorithms generate a power reference to the ESS that opposes the PV fluctuations, reducing them to an acceptable value. Despite their common use, few performance comparisons between the different methods have been presented, especially from a battery status perspective. This is highly important, as different smoothing methods may require the battery to operate at different regimes (i.e., number of cycles and cycles deepness), which directly relates to the battery lifetime performance. This paper intends to fill this gap by analyzing the different methods under the same irradiance profile, and evaluating their capability to limit the RR and maintain the battery State of Charge (SOC) at the end of the day. Moreover, an analysis into the ESS capacity requirements for each of the methods is quantified. Finally, an analysis of the battery cycles and its deepness is performed based on the well-established rainflow cycle counting method.

This article examines some of the tourism indicators and the contribution of tourism to the Nepalese economy. The number of tourists' inflow through bus and air services and their percentages are discussed. Since 1985 to 2016 the... more

This article examines some of the tourism indicators and the contribution of tourism to the Nepalese economy. The number of tourists' inflow through bus and air services and their percentages are discussed. Since 1985 to 2016 the contribution of tourism sector indicators such as the percentage of total foreign exchange earnings and its share in GDP, average expenditure per visitor and average expenditure per visitor per day are discussed with annual data for the period 20001-2015/16. Further, the duration of tourist's stay an annual growth rate of tourist, and percentage change of foreign exchange earnings in the yearly basis are discussed. The data on the number of tourist arrival, their duration of stay and the growth rate in percentage, from 1985 to 2016 and the contribution of the tourism sector to the national economy is presented from 2000/01. The significance is tested using a t-test. Further, this articles examines the prospects, and review of the literature, review of the tourism sector in the periodic plan, and some problems facing the tourism sector and some suggestion for the development of tourism sector. Nepal still is unable to recover its structures damaged by the earthquake of 2015, which has affected the tourist arrival in the country. Furthermore, the article describes the prospects for the tourism industry in Nepal with reference to its biodiversity and natural beauty.

General aspects of the Fluctuation-Dissipation Relation (FDR), and Response Theory are considered. After analyzing the conceptual and historical relevance of fluctuations in statistical mechanics, we illustrate the relation between the... more

General aspects of the Fluctuation-Dissipation Relation (FDR), and Response Theory are considered. After analyzing the conceptual and historical relevance of fluctuations in statistical mechanics, we illustrate the relation between the relaxation of spontaneous fluctuations, and the response to an external perturbation. These studies date back to Einstein's work on Brownian Motion, were continued by Nyquist and Onsager and culminated in Kubo's linear response theory. The FDR has been originally developed in the framework of statistical mechanics of Hamiltonian systems, nevertheless a generalized FDR holds under rather general hypotheses, regardless of the Hamiltonian, or equilibrium nature of the system. In the last decade, this subject was revived by the works on Fluctuation Relations (FR) concerning far from equilibrium systems. The connection of these works with large deviation theory is analyzed. Some examples, beyond the standard applications of statistical mechanics, where fluctuations play a major role are discussed: fluids, granular media, nanosystems and biological systems.