We design a novel empirical framework to examine market efficiency through out-of-sample(OOS) predictability. We frame the classic empirical asset pricing problem as a machine learningclassification problem. We construct classification models to predict return states. The prediction- based...

Although the trade-boosting effect of the Internet is well-documented, two critical questions remain unsatisfactorily answered. First, does the Internet benefit the trade in services greater than the trade in goods? Second, does the Internet eliminate or at least, weaken the negative effect of...

Does faster broadband generate more economic benefits than normal-speed broadband? This study examines the differential economic impacts of broadband of different speeds. Utilizing the broadband availability and speed data from the National Broadband Map, a first-differenced regression analysis...

In this paper, we study the competition model of commercial websites with learning and updating speed, and further analyze the influence of learning and updating speed on the growth of commercial websites from a nonlinear dynamics perspective. Using the center manifold theory and the normal form...

In this paper, we focus on single-index models for longitudinal data. We propose a procedure to estimate the single-index component and the unknown link function based on the combination of the penalized splines and quadratic inference functions. It is shown that the proposed estimation method...