Search results for "stochastic"
showing 10 items of 1018 documents
Inverted and mirror repeats in model nucleotide sequences.
2007
We analytically and numerically study the probabilistic properties of inverted and mirror repeats in model sequences of nucleic acids. We consider both perfect and non-perfect repeats, i.e. repeats with mismatches and gaps. The considered sequence models are independent identically distributed (i.i.d.) sequences, Markov processes and long range sequences. We show that the number of repeats in correlated sequences is significantly larger than in i.i.d. sequences and that this discrepancy increases exponentially with the repeat length for long range sequences.
Econophysics: Scaling and its breakdown in finance
1997
We discuss recent empirical results obtained by analyzing high-frequency data of a stock market index, the Standard and Poor’s 500. We focus on the scaling properties and on its breakdown of the index dynamics. A simple stochastic model, the truncated Levy flight, is illustrated. Successes and limitations of this model are presented. A discussion about similarities and differences between the scaling properties observed in financial markets and in fully developed turbulence is also provided.
First passage time distribution of stationary Markovian processes
2010
The aim of this paper is to investigate how the correlation properties of a stationary Markovian stochastic processes affect the First Passage Time distribution. First Passage Time issues are a classical topic in stochastic processes research. They also have relevant applications, for example, in many fields of finance such as the assessment of the default risk for firms' assets. By using some explicit examples, in this paper we will show that the tail of the First Passage Time distribution crucially depends on the correlation properties of the process and it is independent from its stationary distribution. When the process includes an infinite set of time-scales bounded from above, the FPT…
Does Inflation Targeting Affect the Trade-off Between Output Gap and Inflation Variability?
2002
We utilize a stochastic volatility model to analyse the possible effects of inflation targeting on the trade–off between output gap variability and inflation variability. We find that the adoption of inflation targets (in New Zealand, Australia, Canada, the UK, Sweden and Finland) might result in a more favourable monetary policy trade–off (except in Australia and Finland). This conclusion is reached by comparing, first, the economic performance of targeting countries in the 1980s and the 1990s; and second, the economic performance in the 1990s of targeting and non–targeting countries (the USA, Japan, Switzerland, Germany, France and the Netherlands). We focus on two possible explanations f…
Inflation dynamics in a model with firm entry and (some) heterogeneity
2014
We analyse the incidence of endogenous entry and firm TFP-heterogeneity on the response of aggregate inflation to exogenous shocks. We build up an otherwise standard DSGE model in which the number of firms is endogenously determined and firms differ in their steady state level of productivity. This splits the industry structure into firms of different sizes. Calibrating the different transition rates, across firm sizes and out of the market we reproduce the main features of the distribution of firms in Spain. We then compare the inflation response to technology, interest rate and entry cost shocks, among others. We find that structures in which large (more productive) firms predominate tend…
Effects of Fiscal Stimulus in Structural Models
2010
The paper assesses, using seven structural models used heavily by policymaking institutions, the effectiveness of temporary fiscal stimulus. Models can, more easily than empirical studies, account for differences between fiscal instruments, for differences between structural characteristics of the economy, and for monetary-fiscal policy interactions. Findings are: (i) There is substantial agreement across models on the sizes of fiscal multipliers. (ii) The sizes of spending and targeted transfers multipliers are large. (iii) Fiscal policy is most effective if it has some persistence and if monetary policy accommodates it. (iv) The perception of permanent fiscal stimulus leads to significant…
Risky choices in strategic environments: An experimental investigation of a real options game
2019
Managers frequently make decisions under conditions of fundamental uncertainty due the stochastic nature of the outcomes and competitive rivalry. In this study, we experimentally test a theoretical model under fundamental uncertainty and competitive rivalry by designing a sequential interaction game between two players. The first mover can decide either to choose a sure outcome that assigns a risky outcome to the second mover or to pass the decision to the second mover. If the second player gets the chance to decide, she can choose between a sure outcome, conditioned by the assignment of a risky payoff to the first mover, or the sharing of the risky outcome with the first mover. We then int…
Network-based H∞ output feedback control for uncertain stochastic systems
2013
This paper investigates the problem of network-based Floc, output feedback control for a class of stochastic nonlinear systems. A novel model is proposed to describe the systems taken into two sides of communication channels in the network environment, which is more general than one side of communication channel. The design procedure of observer-based controller is presented, which, guarantees the asymptotic stability in the mean square of the resulting closed-loop system with an H-infinity performance. Finally, a crane example is utilized to show the effectiveness and potential of the developed techniques. Refereed/Peer-reviewed
Evaluation of the power quality from a seawave power farm for different interconnection schemes
2007
In this paper we present an approach to the interconnection of a seawave power farm to the grid The generator type used in the farm is a Permanent Magnet (PM) linear generator driven from the seawaves that generates, therefore, highly distorted emfs. We propose and compare two possible ways to interconnect the farm to the grid. One is based on an approach where for each generator there is a conversion subsystem that permits the direct connection of each generator to the a.c. network, the other one is based on an ac.-d.c. converter that is connected to the generator, the converter is connected to a dc link that can receive the power from every unit and that can supply a dc-ac converter direc…
Advanced techniques for solving groundwater and surface water problems in the context of inverse methods and climate change.
2021
[ES] El tema de la investigación se centra en técnicas avanzadas para manejar problemas de aguas subterráneas y superficiales relacionados con métodos inversos y cambio climático. Los filtros de Kalman, con especial atención en Ensemble Smoother with Multiple Data Assimilation (ES-MDA), se analizan y mejoran para la solución de diferentes tipos de problemas inversos. En particular, la principal novedad es la aplicación de estos métodos para la identificación de series temporales. La primera parte de la tesis, luego de la descripción del método, presenta el desarrollo de un software escrito en Python para la aplicación de la metodología propuesta. El software cuenta con un flujo de trabajo f…