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Bo-Wen Zhou

Publications and source records attributed to Bo-Wen Zhou.

2 recordsLinked to original sources

Reliable Weakly Supervised Learning: Maximize Gain and Maintain Safeness

Weakly supervised data are widespread and have attracted much attention. However, since label quality is often difficult to guarantee, sometimes the use of weakly supervised data will lead to unsatisfactory performance, i.e., performance degradation or poor performance gains. Moreover, it is usually not feasible to manually increase the label quality, which results in weakly supervised learning being somewhat difficult to rely on. In view of this crucial issue, this paper proposes a simple and novel weakly supervised learning framework. We guide the optimization of label quality through a small amount of validation data, and to ensure the safeness of performance while maximizing performance gain. As validation set is a good approximation for describing generalization risk, it can effectively avoid the unsatisfactory performance caused by incorrect data distribution assumptions. We formalize this underlying consideration into a novel Bi-Level optimization and give an effective solution. Extensive experimental results verify that the new framework achieves impressive performance on weakly supervised learning with a small amount of validation data.

cs.LG

Finite volume effects on the chiral phase transition from Dyson-Schwinger equations of QCD

Within the framework of Dyson-Schwinger equations of QCD, we study the finite volume effects on the chiral phase transition, especially the influence on the position of the possible pseudo-critical end point (pCEP). The results show that in the chiral limit case (the current quark mass $m=0$), the absolute value of quark condensate decreases for smaller volumes, and more interestingly, so does the pseudo-critical temperature $T_c(μ=0)$, which is in agreement with the Polyakov Nambu--Jona-Lasinio model result and opposite to the Polyakov linear sigma model prediction. These conclusions hold for $m>0$ case in our calculations. Moreover, the results of pCEP as a function of different volumes show that $T$ of pCEP also decreases for smaller volumes, but $μ$ of pCEP will increase, which are qualitatively more close to Polyakov linear sigma model results. For our model setup, results for systems with a size larger than (5 fm)$^3$ closely approximate those from infinite volume, but if the volume is smaller, the corrections are non-negligible, even significantly affect signatures of the results from an infinite system. There also exists some possibility that, if the system size is too small, the whole phase transition would be crossover, which means no pCEP exists at all. It is no doubt that, finite volume effects deserve further researches.

hep-ph