Search results for "Probability"
showing 10 items of 3417 documents
A study on the degree of relationship between two individuals.
2000
The paper studies the likely degree of relationship between two individuals who could possibly be half sibs. The possible common ancestor was dead, which further complicated the problem. The model used was devised by Thompson [in Rao and Chakraborty (eds): Handbook of Statistics, North-Holland, Amsterdam, 1991] and establishes a correspondence between the possible degree of relationship and certain feasible probability distributions on the number of identical by descent genes. Two statistical approaches are considered: the classical one, in which the maximum likelihood estimation for the parameters of Thompson’s model are obtained, and the Bayesian one, in which the test of the hypothesis o…
Epistemic uncertainty in fault tree analysis approached by the evidence theory
2012
Abstract Process plants may be subjected to dangerous events. Different methodologies are nowadays employed to identify failure events, that can lead to severe accidents, and to assess the relative probability of occurrence. As for rare events reliability data are generally poor, leading to a partial or incomplete knowledge of the process, the classical probabilistic approach can not be successfully used. Such an uncertainty, called epistemic uncertainty, can be treated by means of different methodologies, alternative to the probabilistic one. In this work, the Evidence Theory or Dempster–Shafer theory (DST) is proposed to deal with this kind of uncertainty. In particular, the classical Fau…
TREEZZY2, a Fuzzy Logic Computer Code for Fault Tree and Event Tree Analyses
2004
In conventional approach to reliability analysis using logical trees methodologies, uncertainties in system components or basic events failure probabilities are approached by assuming probability distribution functions. However, data are often insufficient for statistical estimation, and therefore it is required to resort to approximate estimations. Moreover, complicate calculations are needed to propagate uncertainties up to the final results. In our work, in order to take account of the uncertainties in system failure probabilities, the methodology based on fuzzy sets theory is used both in fault tree and event tree analyses. This paper just presents our work in this issue, which resulted…
Risk Assessment and Analysis
2014
Once threats are identified, they must be assessed or evaluated, which is the objective of this chapter. There is usually a large number of threats, making it impossible or unprofitable to analyze them all, meaning selection of the threats that will be addressed is important. It is a decision-making process; an example is proposed and solved by one of the many techniques available. The chapter proposes a very standard requested study, which is the assessment of the economic and financial risks of a project. This is done through a real-life-example, followed by another appraisal, this time devoted to economic issues, as well as another for transportation, introducing the important concept of…
Optimal Flight Path Determination in Turbulent Air: A Modified EKF Approach
2017
By using the Extended Kalman Filter an accurate path following in turbulent air is performed. The procedure employs simultaneously two different EKFs: the first one estimates disturbances, the second one affords to determine the necessary controls displacements for rejecting those ones. To tune the EKFs an optimization algorithm has been designed to automatically determine Process Noise Covariance and Measurement Noise Covariance matrices. The first filter, by using instrumental measurements gathered in turbulent air, estimates wind components. The second one obtains command laws able to follow the desired flight path. To perform this task aerodynamic coefficients have been modified. Such a…
Influence of economic crisis on new SME survival: reality or fiction?
2016
AbstractThe aim of this research was to analyse the survival of new ventures during periods of economic crisis. The article compares survival probability during growth and crisis periods. An empirical study was used to analyse new venture survival probability. Results show that new firms have a greater likelihood of surviving during crisis periods than they do during growth periods. An additional aim of the study was to analyse the survival probability of opportunity and necessity entrepreneurs during crisis periods. Results show that gaps in survival likelihood between opportunity and necessity entrepreneurship are bigger during times of crisis than they are during growth periods.
Quantifying Structural Subsidy Values for Systemically Important Financial Institutions
2013
Abstract Claimants to Systemically Important Financial Institutions (SIFIs) would receive transfers when governments are forced into bailouts. Ex ante, this bailout expectation lowers SIFIs’ daily funding costs. The funding cost advantage reflects both the structural level of the government support and the time-varying market valuation for such a support. Based on a large worldwide sample of banks, we estimate the value of the structural subsidy, by exploiting expectations of state support embedded in credit ratings and by applying the long-run average value of the rating bonus. The value of the structural subsidy was already sizable, 60 basis points (bp), as of the end-2007, before the cri…
Finansinis stabilumas ir koncentracija: besivystančios Europos tyrimas
2016
Šiame straipsnyje tiriamas bankų sektoriaus koncentracijos poveikis finansiniam stabilumui naudojant 134 komercinių bankų iš 17 Vidurio ir Rytų Europos šalių 2007-2012 m. laikotarpio duomenis. Empirinio tyrimo rezultatai pabrėžia vadinamąją „koncentracijos trapumo“ hipotezę, parodydami, kad aukštas koncentracijos lygis bankų sektoriuje yra siejamas su didesne bankų, ypač mažesniųjų, įsipareigojimų neįvykdymo tikimybe. Taip pat parodoma, kad neigiamas koncentracijos poveikis gali būti sumažintas taikant griežtą priežiūros sistemą. Pirmiausia - griežtas oficialus bankų sektoriaus priežiūros įgaliojimas. Antra - skirtingi priimančiosios šalies ir buveinės šalies priežiūros įgaliojimai gali žym…
Robustness of the risk–return relationship in the U.S. stock market
2008
Abstract Using GARCH-in-Mean models, we study the robustness of the risk–return relationship in monthly U.S. stock market returns (1928:1–2004:12) with respect to the specification of the conditional mean equation. The issue is important because in this commonly used framework, unnecessarily including an intercept is known to distort conclusions. The existence of the relationship is relatively robust, but its strength depends on the prior belief concerning the intercept. The latter applies in particular to the first half of the sample, where also the coefficient of the relative risk aversion is smaller and the equity premium greater than in the latter half.
New Refinements of the McKay Conjecture for Arbitrary Finite Groups
2004
Let $G$ be an arbitrary finite group and fix a prime number $p$. The McKay conjecture asserts that $G$ and the normalizer in $G$ of a Sylow $p$-subgroup have equal numbers of irreducible characters with degrees not divisible by $p$. The Alperin-McKay conjecture is a version of this as applied to individual Brauer $p$-blocks of $G$. We offer evidence that perhaps much stronger forms of both of these conjectures are true.