45 research outputs found
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Volatility forecasting for risk management
Recent research has suggested that forecast evaluation on the basis of standard statistical
loss functions could prefer models which are sub-optimal when used in a practical setting.
This paper explores a number of statistical models for predicting the daily volatility of
several key UK financial time series. The out-of-sample forecasting performance of
various linear and GARCH-type models of volatility are compared with forecasts derived
from a multivariate approach. The forecasts are evaluated using traditional metrics, such as
mean squared error, and also by how adequately they perform in a modern risk
management setting. We find that the relative accuracies of the various methods are highly
sensitive to the measure used to evaluate them. Such results have implications for any
econometric time series forecasts which are subsequently employed in financial decisionmaking
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An extreme value theory approach to calculating minimum capital risk requirements
This paper investigates the frequency of extreme events for three LIFFE futures contracts for
the calculation of minimum capital risk requirements (MCRRs). We propose a semiparametric
approach where the tails are modelled by the Generalized Pareto Distribution and
smaller risks are captured by the empirical distribution function. We compare the capital
requirements form this approach with those calculated from the unconditional density and
from a conditional density - a GARCH(1,1) model. Our primary finding is that both in-sample
and for a hold-out sample, our extreme value approach yields superior results than either of
the other two models which do not explicitly model the tails of the return distribution. Since
the use of these internal models will be permitted under the EC-CAD II, they could be widely
adopted in the near future for determining capital adequacies. Hence, close scrutiny of
competing models is required to avoid a potentially costly misallocation capital resources
while at the same time ensuring the safety of the financial system
Prediction of photoperiodic regulators from quantitative gene circuit models
Photoperiod sensors allow physiological adaptation to the changing seasons. The external coincidence hypothesis postulates that a light-responsive regulator is modulated by a circadian rhythm. Sufficient data are available to test this quantitatively in plants, though not yet in animals. In Arabidopsis, the clock-regulated genes CONSTANS (CO) and FLAVIN, KELCH, F-BOX (FKF1) and their lightsensitive proteins are thought to form an external coincidence sensor. We use 40 timeseries of molecular data to model the integration of light and timing information by CO, its target gene FLOWERING LOCUS T (FT), and the circadian clock. Among other predictions, the models show that FKF1 activates FT. We demonstrate experimentally that this effect is independent of the known activation of CO by FKF1, thus we locate a major, novel controller of photoperiodism. External coincidence is part of a complex photoperiod sensor: modelling makes this complexity explicit and may thus contribute to crop improvement
Policy statement issued on year 2000 issues
Computers ; Year 2000 date conversion (Computer systems)