2 research outputs found
Parallelized Interactive Machine Learning on Autonomous Vehicles
Deep reinforcement learning (deep RL) has achieved superior performance in
complex sequential tasks by learning directly from image input. A deep neural
network is used as a function approximator and requires no specific state
information. However, one drawback of using only images as input is that this
approach requires a prohibitively large amount of training time and data for
the model to learn the state feature representation and approach reasonable
performance. This is not feasible in real-world applications, especially when
the data are expansive and training phase could introduce disasters that affect
human safety. In this work, we use a human demonstration approach to speed up
training for learning features and use the resulting pre-trained model to
replace the neural network in the deep RL Deep Q-Network (DQN), followed by
human interaction to further refine the model. We empirically evaluate our
approach by using only a human demonstration model and modified DQN with human
demonstration model included in the Microsoft AirSim car simulator. Our results
show that (1) pre-training with human demonstration in a supervised learning
approach is better and much faster at discovering features than DQN alone, (2)
initializing the DQN with a pre-trained model provides a significant
improvement in training time and performance even with limited human
demonstration, and (3) providing the ability for humans to supply suggestions
during DQN training can speed up the network's convergence on an optimal
policy, as well as allow it to learn more complex policies that are harder to
discover by random exploration.Comment: 6 pages, NAECON 2018 - IEEE National Aerospace and Electronics
Conferenc
Automatic \u3csup\u3e13\u3c/sup\u3eC Chemical Shift Reference Correction of Protein NMR Spectral Data Using Data Mining and Bayesian Statistical Modeling
Nuclear magnetic resonance (NMR) is a highly versatile analytical technique for studying molecular configuration, conformation, and dynamics, especially of biomacromolecules such as proteins. However, due to the intrinsic properties of NMR experiments, results from the NMR instruments require a refencing step before the down-the-line analysis. Poor chemical shift referencing, especially for 13C in protein Nuclear Magnetic Resonance (NMR) experiments, fundamentally limits and even prevents effective study of biomacromolecules via NMR. There is no available method that can rereference carbon chemical shifts from protein NMR without secondary experimental information such as structure or resonance assignment.
To solve this problem, we constructed a Bayesian probabilistic framework that circumvents the limitations of previous reference correction methods that required protein resonance assignment and/or three-dimensional protein structure. Our algorithm named Bayesian Model Optimized Reference Correction (BaMORC) can detect and correct 13C chemical shift referencing errors before the protein resonance assignment step of analysis and without a three-dimensional structure. By combining the BaMORC methodology with a new intra-peaklist grouping algorithm, we created a combined method called Unassigned BaMORC that utilizes only unassigned experimental peak lists and the amino acid sequence.
Unassigned BaMORC kept all experimental three-dimensional HN(CO)CACB-type peak lists tested within ± 0.4 ppm of the correct 13C reference value. On a much larger unassigned chemical shift test set, the base method kept 13C chemical shift referencing errors to within ± 0.45 ppm at a 90% confidence interval. With chemical shift assignments, Assigned BaMORC can detect and correct 13C chemical shift referencing errors to within ± 0.22 at a 90% confidence interval. Therefore, Unassigned BaMORC can correct 13C chemical shift referencing errors when it will have the most impact, right before protein resonance assignment and other downstream analyses are started. After assignment, chemical shift reference correction can be further refined with Assigned BaMORC.
To further support a broader usage of these new methods, we also created a software package with web-based interface for the NMR community. This software will allow non-NMR experts to detect and correct 13C referencing errors at critical early data analysis steps, lowering the bar of NMR expertise required for effective protein NMR analysis