Scale-out applications have emerged as the dominant Internet services today. A request in a scale-out workload generally involves task partitioning and merging with barrier synchronization, making it difficult to predict the request tail latency to meet stringent tail Service Level Objectives (SLOs). In this paper, we find that the request tail latency can be faithfully predicted, in the high l...

The estimation of GARCH models by QML with variance targeting requires at least a ...nite unconditional fourth moment in the observed data  to ensure Gaussian asymptotics. However, many ...nancial returns series may not have a fourth moment. We robustify the method against heavy tails by exploiting new tail-trimming techniques for both the ...rst step variance estimator and the second step cr...

We consider the problem of online learning in settings in which we want to compete not simply with the rewards of the best expert or stock, but with the best trade-off between rewards and risk. Motivated by finance applications, we consider two common measures balancing returns and risk: the Sharpe ratio [7] and the mean-variance criterion of Markowitz [6]. We first provide negative results est...

The fundamental purpose of investing in stocks is to make a profit. But the stock investment, income always accompanies risk. In order reduce risk greater returns, investor will be two or more portfolio together invest. This study examines return and using minimal variance maximum Sharpe ratio model, based on Markowitz mean-variance theory, identify best for given preference. model risk-averse ...

In this paper, a critical Galton-Watson branching process with immigration Zn is studied. We first obtain the convergence rate of harmonic moment Zn. Then large deviation $${S_{{Z_n}}}≔ \sum\nolimits_{i = 1}^{{Z_n}} {{X_i}} $$ obtained, where {Xi} sequence independent and identically distributed zero-mean random variables tail index α > 2. shall see that converging determined by mean, variance ...