Results 131 to 140 of about 165,995,511 (248)

The Accuracy Smoothness Dilemma in Prediction: A Novel Multivariate M‐SSA Forecast Approach

open access: yesJournal of Time Series Analysis, EarlyView.
ABSTRACT Forecasting presents a complex estimation challenge, as it involves balancing multiple, often conflicting, priorities and objectives. Conventional forecast optimization methods typically emphasize a single metric, such as minimizing the mean squared error (MSE), which may neglect other crucial aspects of predictive performance. To address this
Marc Wildi
wiley   +1 more source

Asymptotics of Time‐Varying Processes in Continuous‐Time Using Locally Stationary Approximations

open access: yesJournal of Time Series Analysis, EarlyView.
ABSTRACT We introduce a general theory on stationary approximations for locally stationary continuous‐time processes. Based on the stationary approximation, we use θ$$ \theta $$‐weak dependence to establish laws of large numbers and central limit type results under different observation schemes.
Robert Stelzer, Bennet Ströh
wiley   +1 more source

Reinforcement Learning for Jump‐Diffusions, With Financial Applications

open access: yesMathematical Finance, EarlyView.
ABSTRACT We study continuous‐time reinforcement learning (RL) for stochastic control in which system dynamics are governed by jump‐diffusion processes. We formulate an entropy‐regularized exploratory control problem with stochastic policies to capture the exploration–exploitation balance essential for RL.
Xuefeng Gao, Lingfei Li, Xun Yu Zhou
wiley   +1 more source

Response of Tree-Ring Density to Climate in Maine, U.S.A.

open access: yes, 1979
Cores of red spruce (Picea rubens Sarg.) from three upper-elevation sites in Maine, U.S.A., were X-rayed, and minimum and maximum wood densities as well as ring widths were mechanically recorded.
Conkey, Laura E.
core  

On Short‐Term Behavior of Implied Volatility for Index Options

open access: yesMathematical Finance, EarlyView.
ABSTRACT This paper investigates short‐term behavior of implied volatility of derivatives written on a market index when the index is constructed using a ranking procedure. Even when stock prices follow geometric Brownian motion dynamics, the ranking mechanism can lead to the observed term structure of at‐the‐money (ATM) implied volatility skew for ...
Huy N. Chau, Duy Nguyen, Thai Nguyen
wiley   +1 more source

Probing the molecular determinants of emission enhancement in RNA aptamer–metal complex systems

open access: yesPhotochemistry and Photobiology, EarlyView.
Light up aptamer: fluorophore pairs are widely used in sensing and imaging, with coordination complex fluorophores providing specific benefits due to their long‐lived emission. Here, we examined key structural and electronic features of these metal complexes to identify the requirements for productive engagement with an RNA aptamer.
Sarah M. Kriger   +3 more
wiley   +1 more source

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