Diffusion Model-Augmented Behavioral Cloning

Imitation learning addresses the challenge of learning by observing an expert's demonstrations without access to reward signals from environments. Most existing imitation learning methods that do not require interacting with environments either model the expert distribution as the conditional probability p(a|s) (e.g., behavioral cloning, BC) or the joint probability p(s, a) (e.g., implicit behavioral cloning). Despite its simplicity, modeling the conditional probability with BC usually struggles with generalization. While modeling the joint probability can lead to improved generalization performance, the inference procedure can be time-consuming and it often suffers from manifold overfitting. This work proposes an imitation learning framework that benefits from modeling both the conditional and joint probability of the expert distribution. Our proposed diffusion model-augmented behavioral cloning (DBC) employs a diffusion model trained to model expert behaviors and learns a policy to optimize both the BC loss (conditional) and our proposed diffusion model loss (joint). DBC outperforms baselines in various continuous control tasks in navigation, robot arm manipulation, dexterous manipulation, and locomotion. We design additional experiments to verify the limitations of modeling either the conditional probability or the joint probability of the expert distribution as well as compare different generative models

Improved Breath Phase and Continuous Adventitious Sound Detection in Lung and Tracheal Sound Using Mixed Set Training and Domain Adaptation

Previously, we established a lung sound database, HF_Lung_V2 and proposed convolutional bidirectional gated recurrent unit (CNN-BiGRU) models with adequate ability for inhalation, exhalation, continuous adventitious sound (CAS), and discontinuous adventitious sound detection in the lung sound. In this study, we proceeded to build a tracheal sound database, HF_Tracheal_V1, containing 11107 of 15-second tracheal sound recordings, 23087 inhalation labels, 16728 exhalation labels, and 6874 CAS labels. The tracheal sound in HF_Tracheal_V1 and the lung sound in HF_Lung_V2 were either combined or used alone to train the CNN-BiGRU models for respective lung and tracheal sound analysis. Different training strategies were investigated and compared: (1) using full training (training from scratch) to train the lung sound models using lung sound alone and train the tracheal sound models using tracheal sound alone, (2) using a mixed set that contains both the lung and tracheal sound to train the models, and (3) using domain adaptation that finetuned the pre-trained lung sound models with the tracheal sound data and vice versa. Results showed that the models trained only by lung sound performed poorly in the tracheal sound analysis and vice versa. However, the mixed set training and domain adaptation can improve the performance of exhalation and CAS detection in the lung sound, and inhalation, exhalation, and CAS detection in the tracheal sound compared to positive controls (lung models trained only by lung sound and vice versa). Especially, a model derived from the mixed set training prevails in the situation of killing two birds with one stone.Comment: To be submitted, 31 pages, 6 figures, 5 table

How stress influences creativity in game-based situations:analysis of stress hormones, negative emotions, and working memory

This study aims to integrate neuroscientific techniques into a behavioral experimental design to investigate how stress stimuli may influence stress hormones and negative emotions, subsequently affecting working memory (WM) and creativity in game-based situations. Ninety-six college students participated in this study, in which a game-based experiment lasting 90 min was employed. The main findings were that (1) the employed stress stimuli influence creativity during gaming through two routes: enhancing creativity through cortisol concentration and WM and decreasing creativity by provoking promotion-focused negative emotions (frustration and anger); and (2) the subjective negative emotions and objective cortisol responses do not consistently predict WM and creativity in game-based situations. Accordingly, appropriate challenges or stressors that help increase the cortisol concentration to an attentional level without provoking a strong sense of promotion-focused negative emotions should be considered when designing games aimed at teaching creativity

1-(2-Bromo-2-de­oxy-β-d-xylofuranos­yl)uracil

In the title compound, C9H11BrN2O5, the ribofuran­ose ring has a C2-exo, C3-endo twist configuration and is attached to the uracil unit via a β-N1-glycosidic bond. The crystal structure is stabilized by two inter­molecular O—H⋯O inter­actions and one inter­molecular N—H⋯O inter­action