Search results for "probability"

Output Feedback Control of Discrete Impulsive Switched Systems with State Delays and Missing Measurements

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/283426 Open Access This paper is concerned with the problem of dynamic output feedback (DOF) control for a class of uncertain discrete impulsive switched systems with state delays and missing measurements. The missing measurements are modeled as a binary switch sequence specified by a conditional probability distribution. The problem addressed is to design an output feedback controller such that for all admissible uncertainties, the closed-loop system is exponentially stable in mean square sense. By using the average dwell time approach a…

Bot or not? a case study on bot recognition from web session logs

2018

This work reports on a study of web usage logs to verify whether it is possible to achieve good recognition rates in the task of distinguishing between human users and automated bots using computational intelligence techniques. Two problem statements are given, offline (for completed sessions) and on-line (for sequences of individual HTTP requests). The former is solved with several standard computational intelligence tools. For the second, a learning version of Wald’s sequential probability ratio test is used.

Probability Distribution of the Residence Times in Periodically Fluctuating Metastable Systems

1998

We investigate experimentally and numerically the probability distribution of the residence times in periodically fluctuating metastable systems. The experiments are performed in a physical metastable system which is the series of a biasing resistor with a tunnel diode in parallel to a capacitor. The numerical simulations are performed in an overdamped model system with a time-dependent potential. We investigate both the cases where the system is deterministically overall-stable and overall-unstable. In the overall-unstable regime, the experimental and the numerically investigated systems show noise enhanced stability in the presence of a finite amount of noise. The determined P(T) is mult…

Explicit Granger causality in kernel Hilbert spaces

2020

Granger causality (GC) is undoubtedly the most widely used method to infer cause-effect relations from observational time series. Several nonlinear alternatives to GC have been proposed based on kernel methods. We generalize kernel Granger causality by considering the variables cross-relations explicitly in Hilbert spaces. The framework is shown to generalize the linear and kernel GC methods, and comes with tighter bounds of performance based on Rademacher complexity. We successfully evaluate its performance in standard dynamical systems, as well as to identify the arrow of time in coupled R\"ossler systems, and is exploited to disclose the El Ni\~no-Southern Oscillation (ENSO) phenomenon f…

Analytical representation of bimodality in bivariate distribution of chain length and chemical composition of copolymers

2022

Abstract Tuning the bimodality of microstructural features in polymers has provided novel properties and applications. A classic example is to overcome the trade-off between processability and mechanical properties in polyolefins. A recent example is to decrease the interfacial tension in blending incompatible polymers. Therefore, the development of a bimodality index (BI), especially for the chain length distribution (CLD) and the chemical composition distribution (CCD), is crucial for the quantitative design of materials. This study introduces quantitative expressions for the bimodality of univariate CLD on the linear scale, and CCD. Moreover, we develop a bimodality criterion for bivaria…

Book Review: Approximation with Positive Linear Operators and Linear Combinations By: Vijay Gupta, Gancho Tachev Series: Developments in Mathematics,…

2020

On estimating contemporaneous quarterly regional GDP

2007

Subnational regional jurisdictions rarely have at their disposal a reasonable array of timely statistics to monitor their economic condition. In light of this, we develop a procedure that simultaneously estimates a quarterly time series for all regions of a country based upon quarterly national and annual regional data. While other such techniques exist, we suggest a temporal error structure that eliminates possible spurious jumps. Using our approach, regional analysts should now be able to distribute national growth among regions as soon as quarterly national figures are released. In a Spanish application, we detail some practicalities of the process and show that our proposal produces bet…

Input-output finite-time stability of positive switched linear systems with state delays

2013

This paper is concerned with the problem of input-output finite-time stability (IO-FTS) for a class of discrete-time positive switched systems with time-varying delays. Two sufficient conditions for the existence of IO-FTS of such systems with respect to two different input signals are presented, respectively. All the results obtained are formulated in a set of linear inequalities. Two numerical examples are given to illustrate the effectiveness of the proposed results.

Internal Time and Innovation

2003

Consider a physical system that may be observed through time-varying quantities x t , where t stands for time that may be discrete or continuous. The set x t may be a realization of a deterministic system, e.g. a unique solution of a differential equation, or a stochastic process. In the latter case each x t is a random variable. We are interested in the global evolution of the system, not particular realizations x t , from the point of view of innovation. We call the evolution innovative if the dynamics of the system is such that there is a gain of information about the system as time increases. Our purpose is to associate the concept of internal time with such systems. The internal time w…

Stability of the performance of thin film modules during one year of operation

2012

At the University of Agder in Grimstad, Southern Norway, a test bench for photovoltaic modules is in operation since December 2010. Currently, various c-Si as well as aSi, CIS and HIT modules are under investigation. This project is part of the Norwegian contribution to IEA PVPS Task13. The paper focuses on the stability of the modules' MPP-performance in the course of one year. For this purpose, data on the DC response are logged together with irradiance and module temperature at one-minute intervals. Data analysis is performed in monthly blocks. The modeling involves two steps. First, the short-circuit current is expressed as function of irradiance and module temperature. Then, the MPP po…