Online learning algorithms are designed to learn even when their input is generated by an adversary. The widely-accepted formal definition of an online algorithm’s ability to learn is the game-theoretic notion of regret. We argue that the standard definition of regret becomes inadequate if the adversary is allowed to adapt to the online algorithm’s actions. We define the alternative notion of p...

night eating syndrome is a common disorder in eating behaviors that occurs in close relation to the night time sleep cycle. although eating disorders are common in society, night eating syndrome has been left neglected by health care professionals. in this report we present a case of eating disorder that exhibits some novel features of night eating syndrome. our case was a progressed type of ea...

W characterize the effect of anticipated regret on consumer decisions and on firm profits and policies in an advance selling context where buyers have uncertain valuations. Advance purchases trigger action regret if valuations turn out to be lower than the price paid, whereas delaying purchase may cause inaction regret from missing a discount or facing a stockout. Consumers whom we describe as ...

We present an algorithm that achieves almost optimal pseudo-regret bounds against adversarial and stochastic bandits. Against adversarial bandits the pseudo-regret is O ( K √ n log n ) and against stochastic bandits the pseudo-regret is O ( ∑ i(log n)/∆i). We also show that no algorithm with O (log n) pseudo-regret against stochastic bandits can achieve Õ ( √ n) expected regret against adaptive...

Regret minimization is important in both the Multi-Armed Bandit problem and Monte-Carlo Tree Search (MCTS). Recently, simple regret, i.e., the regret of not recommending the best action, has been proposed as an alternative to cumulative regret in MCTS, i.e., regret accumulated over time. Each type of regret is appropriate in different contexts. Although the majority of MCTS research applies the...

BACKGROUND Parental hesitancy for recommended childhood vaccines is a growing public health concern influenced by various factors. This study aimed to explore regret regarding parental decisions to vaccinate their children via possible correlations between anticipated regret, altruism, coping strategies, and parents' attitudes toward the vaccination of their children. METHODS The study was co...

BACKGROUND & OBJECTIVES It is not known if optimism influences regret following major reconstructive breast surgery. We examined the relationship between dispositional optimism, major complications and decision regret in patients undergoing microsurgical breast reconstruction. METHODS A consecutive series of 290 patients were surveyed. Independent variables were: (1) dispositional optimism an...