Browsing by Author "Li, Yao"

Now showing 1 - 4 of 4
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    Analysis of B Meson Decays to Three Charged Pions
    Li, Yao (Virginia Tech, 2015-12-23)
    Decays of B mesons to three-body charmless final states probe the properties of the weak interaction through their dependence on the complex quark couplings in the CKM matrix. They also test dynamical models for hadronic B decays. Based on a sample of 772 million BB pairs collected by the Belle experiment, we present a study of direct CP violation in the decay of charged B to three charged pions.
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    Contextual Impact on SNS Users’ Privacy Decisions: A Cross Cultural Study
    Rho, Ha Rim; Li, Yao (2018-04-21)
    Social network users with different cultural backgrounds have different privacy attitudes and behaviors. This study is to explore the mechanisms behind the cultural differences in privacy decisions. The findings have implications on customizing privacy technologies in different cultures.
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    Diminishing storage returns of reservoir construction
    Li, Yao; Zhao, Gang; Allen, George H.; Gao, Huilin (Nature Portfolio, 2023-06-13)
    Surface water reservoirs are increasingly being relied upon to meet rising demands in the context of growing population and changing climate. However, the amount of water available in reservoirs (and the corresponding trends) have not been well quantified at the global scale. Here we use satellite observations to estimate the storage variations of 7245 global reservoirs from 1999 to 2018. Total global reservoir storage has increased at a rate of 27.82 ± 0.08 km3/yr, which is mainly attributed to the construction of new dams. However, the normalized reservoir storage (NS)—the ratio of the actual storage to the storage capacity—has declined by 0.82 ± 0.01%. The decline of NS values is especially pronounced in the global south, while the global north mainly exhibits an NS increase. With predicted decreasing runoff and increasing water demand, these observed diminishing storage returns of reservoir construction will likely persist into the future.
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    Examination of long-run performance of momentum portfolios: Implications for the sources and profitability of momentum
    Li, Yao (Virginia Tech, 2019-09-20)
    This dissertation investigates the long-term performance of momentum portfolios. Its results show striking asymmetries for winners and losers and imply potentially different causes for the winner and loser components of momentum. After separately examining winners and losers relative to their respective benchmark portfolios with no momentum, we find winner momentum is smaller in magnitude, persists only for six months, and its higher return fully reverses. This is consistent with the notion that winner momentum is an overreaction to positive news and potentially destabilizing. Loser momentum is larger in magnitude, lasts for about one year, and its lower return does not reverse in the long run. This is consistent with the notion that loser momentum is an underreaction to negative news and suggests investors hold on to losers for too long. The lack of reversal for losers departs from prior studies whose findings are driven by the use of monthly rebalanced portfolio. Rebalancing cumulates an upward bias caused by noise-induced price volatility, which disproportionately affects losers more. This greater upward bias in losers creates an illusion that the winner minus loser return reverses. More appropriate approaches such as the buy-and-hold portfolio documents significantly less reversal. Existing theories that potentially conform to the overreaction of winners and underreaction of losers include overconfidence (Daniel, Hirshleifer, and Subrahmanyam, 1998), representativeness and conservatism (Barberis, Shleifer, and Vishny, 1998), interaction between agents holding asymmetric information (Hong and Stein, 1999), and investors' asymmetric response to fund performance (Vayanos and Woolley, 2013).