Policy-Adaptive Estimator Selection for Off-Policy Evaluation

Off-policy evaluation (OPE) aims to accurately evaluate the performance of counterfactual policies using only offline logged data. Although many estimators have been developed, there is no single estimator that dominates the others, because the estimators' accuracy can vary greatly depending on a given OPE task such as the evaluation policy, number of actions, and noise level. Thus, the data-driven estimator selection problem is becoming increasingly important and can have a significant impact on the accuracy of OPE. However, identifying the most accurate estimator using only the logged data is quite challenging because the ground-truth estimation accuracy of estimators is generally unavailable. This paper studies this challenging problem of estimator selection for OPE for the first time. In particular, we enable an estimator selection that is adaptive to a given OPE task, by appropriately subsampling available logged data and constructing pseudo policies useful for the underlying estimator selection task. Comprehensive experiments on both synthetic and real-world company data demonstrate that the proposed procedure substantially improves the estimator selection compared to a non-adaptive heuristic.Comment: accepted at AAAI'2

Influence of the Antarctic sea-ice anomaly upon largescale atmospheric circulation in the Southern Hemisphere by using AGCM

第3回極域科学シンポジウム/第35回極域気水圏シンポジウム 11月30日（金） 国立国語研究所 ２階多目的

Modulation in interannual sea ice patterns in the Southern Ocean in association with large-scale atmospheric mode shift

We verified that the synchronous propagations of the spatial patterns of sea ice concentration (SIC) of wavenumber 2 around the Antarctic occurred only for the period 1984 to 1994. An empirical orthogonal function (EOF) analysis of satellite data for 1979-2003 objectively demonstrates that the spatial pattern of SIC propagated eastward only in 1984-1994, in other years, it did not. Our results show that interannual variations in SIC patterns are associated with differences in the dominant large-scale atmospheric patterns. In non-propagating years, variance of the tropospheric Antarctic oscillation (AAO) predominated. However, in propagating years, the AAO variance was subdominant to that of the Pacific South American (PSA) teleconnection pattern having a 4-year period. Such periodic PSA enables the SIC anomalies to propagate eastward with a periodically reinforced dipole pattern. The shift of large-scale atmospheric variability is one possible cause of the modulation in the SIC pattern. The switch of the atmospheric EOF leading mode from the PSA pattern to the AAO in the mid-1990s corresponded to the modulation in the SIC pattern and supports the presence of the atmospheric climate shifts

Application of Holography to the Study of Hearing -Analysis of the eardrum vibration-

Holographic interferometry is a specific technique for the analysis of vibration. Images of vibrating body reconstructed with this method are superimposed by interference fringes. As the fringes represent iso-amplitude contours like those on geodesic maps, the mode of vibration is clearly discernible at a glance. As the amplitudes relating to each fringe are calibrated according to the wavelength of the laserlight the value is most precise and submicroscopic, viz., 10(-5)cm order. In this study eardrum vibrations are investigated by means of time-averaged holography on frogs and guinea-pigs. The first fringe appeared at about 80 dB sound pressure level in both animals. The vibratory pattern appeared to be constant depending upon the number of frequencies of the test tones. At low frequency the eardrum showed rather a simple pattern; with increasing frequencies the pattern became more complicated containing two or more mounds

3′UTR Length-Dependent Control of SynGAP Isoform α2 mRNA by FUS and ELAV-like Proteins Promotes Dendritic Spine Maturation and Cognitive Function

FUS is an RNA-binding protein associated with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). Previous reports have demonstrated intrinsic roles of FUS in synaptic function. However, the mechanism underlying FUS’s regulation of synaptic morphology has remained unclear. We found that reduced mature spines after FUS depletion were associated with the internalization of PSD-95 within the dendritic shaft. Mass spectrometry of PSD-95-interacting proteins identified SynGAP, whose expression decreased after FUS depletion. Moreover, FUS and the ELAV-like proteins ELAVL4 and ELAVL1 control SynGAP mRNA stability in a 3′UTR length-dependent manner, resulting in the stable expression of the alternatively spliced SynGAP isoform α2. Finally, abnormal spine maturation and FTLD-like behavioral deficits in FUS-knockout mice were ameliorated by SynGAP α2. Our findings establish an important link between FUS and ELAVL proteins for mRNA stability control and indicate that this mechanism is crucial for the maintenance of synaptic morphology and cognitive function