Rule-based portfolio construction strategies are rising as investmentdemand grows, and smart beta strategies are becoming a trend amonginstitutional investors. Smart beta strategies have high transparency, lowmanageme...Rule-based portfolio construction strategies are rising as investmentdemand grows, and smart beta strategies are becoming a trend amonginstitutional investors. Smart beta strategies have high transparency, lowmanagement costs, and better long-term performance, but are at the risk ofsevere short-term declines due to a lack of Risk Control tools. Although thereare some methods to use historical volatility for Risk Control, it is still difficultto adapt to the rapid switch of market styles. How to strengthen the RiskControl management of the portfolio while maintaining the original advantagesof smart beta has become a new issue of concern in the industry. Thispaper demonstrates the scientific validity of using a probability prediction forposition optimization through an optimization theory and proposes a novelnatural gradient boosting (NGBoost)-based portfolio optimization method,which predicts stock prices and their probability distributions based on non-Bayesian methods and maximizes the Sharpe ratio expectation of positionoptimization. This paper validates the effectiveness and practicality of themodel by using the Chinese stock market, and the experimental results showthat the proposed method in this paper can reduce the volatility by 0.08 andincrease the expected portfolio cumulative return (reaching a maximum of67.1%) compared with the mainstream methods in the industry.展开更多
To the Editor:In neurosurgery,intraoperative fluid administration is essential in maintaining appropriate systemic and cerebral perfusion pressure,oxygenation,and metabolism.Meningioma resection can involve massive in...To the Editor:In neurosurgery,intraoperative fluid administration is essential in maintaining appropriate systemic and cerebral perfusion pressure,oxygenation,and metabolism.Meningioma resection can involve massive intraoperative blood loss due to an abundant blood supply in structures.Moreover,the routine use of mannitol during meningioma resection may affect hemodynamic stability.Fluid overload is correlated to neurological,pulmonary,or gastrointestinal(GI)edema,which has unfavorable outcomes.[1]Thus,neurosurgeries,particularly meningioma resection,require individualized fluid therapy to achieve a balance between inadequate fluid and fluid overload.展开更多
基金supported by the National Natural Science Foundation of China[Grant Number 61902349].
文摘Rule-based portfolio construction strategies are rising as investmentdemand grows, and smart beta strategies are becoming a trend amonginstitutional investors. Smart beta strategies have high transparency, lowmanagement costs, and better long-term performance, but are at the risk ofsevere short-term declines due to a lack of Risk Control tools. Although thereare some methods to use historical volatility for Risk Control, it is still difficultto adapt to the rapid switch of market styles. How to strengthen the RiskControl management of the portfolio while maintaining the original advantagesof smart beta has become a new issue of concern in the industry. Thispaper demonstrates the scientific validity of using a probability prediction forposition optimization through an optimization theory and proposes a novelnatural gradient boosting (NGBoost)-based portfolio optimization method,which predicts stock prices and their probability distributions based on non-Bayesian methods and maximizes the Sharpe ratio expectation of positionoptimization. This paper validates the effectiveness and practicality of themodel by using the Chinese stock market, and the experimental results showthat the proposed method in this paper can reduce the volatility by 0.08 andincrease the expected portfolio cumulative return (reaching a maximum of67.1%) compared with the mainstream methods in the industry.
文摘To the Editor:In neurosurgery,intraoperative fluid administration is essential in maintaining appropriate systemic and cerebral perfusion pressure,oxygenation,and metabolism.Meningioma resection can involve massive intraoperative blood loss due to an abundant blood supply in structures.Moreover,the routine use of mannitol during meningioma resection may affect hemodynamic stability.Fluid overload is correlated to neurological,pulmonary,or gastrointestinal(GI)edema,which has unfavorable outcomes.[1]Thus,neurosurgeries,particularly meningioma resection,require individualized fluid therapy to achieve a balance between inadequate fluid and fluid overload.
