Competing for Shareable Arms in Multi-Player Multi-Armed Bandits

Competitions for shareable and limited resources have long been studied with strategic agents. In reality, agents often have to learn and maximize the rewards of the resources at the same time. To design an individualized competing policy, we model the competition between agents in a novel multi-player multi-armed bandit (MPMAB) setting where players are selfish and aim to maximize their own rewards. In addition, when several players pull the same arm, we assume that these players averagely share the arms' rewards by expectation. Under this setting, we first analyze the Nash equilibrium when arms' rewards are known. Subsequently, we propose a novel SelfishMPMAB with Averaging Allocation (SMAA) approach based on the equilibrium. We theoretically demonstrate that SMAA could achieve a good regret guarantee for each player when all players follow the algorithm. Additionally, we establish that no single selfish player can significantly increase their rewards through deviation, nor can they detrimentally affect other players' rewards without incurring substantial losses for themselves. We finally validate the effectiveness of the method in extensive synthetic experiments.Comment: ICML 202

Rethinking the Evaluation Protocol of Domain Generalization

Domain generalization aims to solve the challenge of Out-of-Distribution (OOD) generalization by leveraging common knowledge learned from multiple training domains to generalize to unseen test domains. To accurately evaluate the OOD generalization ability, it is necessary to ensure that test data information is unavailable. However, the current domain generalization protocol may still have potential test data information leakage. This paper examines the potential risks of test data information leakage in two aspects of the current protocol: pretraining on ImageNet and oracle model selection. We propose that training from scratch and using multiple test domains would result in a more precise evaluation of OOD generalization ability. We also rerun the algorithms with the modified protocol and introduce a new leaderboard to encourage future research in domain generalization with a fairer comparison

High serum total cholesterol levels is a risk factor of ischemic stroke for general Japanese population: The JPHC study

Background:High serum total cholesterol levels represent a risk factor of ischemic stroke in Western countries. However, this association has not been thoroughly investigated in Asian populations where the incidence of stroke is high.Methods:Participants were 11,727 men and 21,742 women aged 40–69 years, all free of cardiovascular disease and cancer at baseline. During the median 12-year follow-up, we documented 612 ischemic stroke (293 lacunar infarction, 107 large-artery occlusive infarctions, and 168 embolic infarctions).Results:Excess risk of ischemic stroke was observed in men with serum total cholesterol levels of ≥6.21 mmol/L than those with the lowest category (<4.65 mmol/L), but not in women. The multivariable hazard ratios (HRs) and 95% confidence interval (95% CI) were 1.63 (1.14–2.35) for men and 1.03 (0.69–1.55) for women. The corresponding HRs of large-artery occlusive infarction were 2.86 (1.31–6.27) for men and 0.75 (0.28–2.01) for women. Serum total cholesterol levels were not associated with risk of lacunar or embolic infarction for either sex.Conclusions:High serum total cholesterol is a risk factor of ischemic stroke, specifically large-artery occlusive infarction for Japanese men

Association between markers of arterial stiffness and atrial fibrillation in the Circulatory Risk in Communities Study (CIRCS).

Background and aims:Limited evidence is available on the association between markers of arterial stiffness and the prevalence of atrial fibrillation among Asian populations. Therefore, we examined those associations in the Japanese population.Methods:We conducted a cross-sectional population-based study of 4264 men and women aged 40-79 years. The augmentation index (AI), a marker of arterial stiffness, was calculated as the ratio of central pulse pressure/brachial pulse pressure, where the AI and central aortic pressure were measured by an automated tonometer: the HEM-9000AI device (Omron Healthcare co., Kyoto, Japan). Atrial fibrillation was estimated by the Minnesota codes using resting electrocardiograph (ECG).Results:The prevalence of atrial fibrillation and total arrhythmia were higher with larger AI values. These associations did not change after adjustment for known cardiovascular risk factors. The multivariable odd ratios (95% confidence intervals) in the highest versus lowest tertiles of AI were 3.4 (1.4-8.6, p for trend = 0.008) for atrial fibrillation and 1.8 (1.2-2.7, p for trend = 0.004) for total arrhythmia. There was no association of central or brachial pulse pressure levels with the prevalence of atrial fibrillation or total arrhythmia.ConclusionAI values, but not brachial or central pulse pressures, were positively associated with the prevalence of atrial fibrillation and total arrhythmia, independent of cardiovascular risk factors

Association of cigarette smoking with radial augmentation index: the Circulatory Risk in Communities Study (CIRCS)

This study aimed to assess the association of cigarette smoking with radial augmentation index among the Asian general population. We conducted a cross-sectional population-based study including 1593 men and 2671 women aged 40–79 years. Smoking status was ascertained through interviews, and the number of pack-years was calculated. The radial augmentation index was defined as the ratio of central pulse pressure to brachial pulse pressure, as measured using an automated tonometer: the HEM-9000AI (Omron Healthcare co., Kyoto, Japan). There was a higher prevalence of an increased radial augmentation index among current male smokers who smoked ≥ 30 cigarettes/day and all female smokers than among never smokers. After adjusting for known risk factors of atherosclerosis, the multivariable odds ratio (OR) [95% confidence interval (CI)] for a high radial augmentation index for current male smokers who smoked ≥30 cigarettes/day compared with never smokers was 1.9 (1.1–3.4). The multivariable OR (95% CI) for a high radial augmentation index for former female smokers and current female smokers compared with never smokers was 1.8 (1.2–2.7) and 2.5 (1.6–3.9), respectively. Moreover, smoking pack-years was positively associated with a high radial augmentation index in both sexes. There were no relationship between smoking status and high central or brachial pulse pressures among subjects of either sex. In conclusion, cigarette smoking and cumulative smoking exposure were positively associated with an increased radial augmentation index in men who smoked heavily and in women

The Circulatory Risk in Communities Study (CIRCS): A Long-Term Epidemiological Study for Lifestyle-Related Disease Among Japanese Men and Women Living in Communities

The Circulatory Risk in Communities Study (CIRCS) is an ongoing community-based epidemiological study of lifestyle-related disease involving dynamic prospective cohorts of approximately 12,000 adults from five communities of Japan: Ikawa, Ishizawa and Kita-Utetsu (Akita Prefecture), Minami-Takayasu (Osaka Prefecture), Noichi (Kochi Prefecture), and Kyowa (Ibaraki Prefecture). One of the most notable features of CIRCS is that it is not only an observational cohort study to identify risk factors for cardiovascular diseases (CVD), such as stroke, coronary heart disease, and sudden cardiac death, but it also involves prevention programs for CVD. Using basic, clinical, epidemiological, and statistical techniques, CIRCS has clarified characteristics of CVD and the related risk factors to develop specific methodologies towards CVD prevention in Japanese middle-aged or older adults for more than half a century