The Sequential Sentence Classification task within the domain of medical abstracts, termed as SSC, involves the categorization of sentences into pre-defined headings based on their roles in conveying critical information in the abstract. In the SSC task, sentences are often sequentially related to each other. For this reason, the role of sentence embedding is crucial for capturing both the semantic information between words in the sentence and the contextual relationship of sentences within the abstract to provide a comprehensive representation for better classification. In this paper, we present a hierarchical deep learning model for the SSC task. First, we propose a LSTM-based network with multiple feature branches to create well-presented sentence embeddings at the sentence level. To perform the sequence of sentences, a convolutional-recurrent neural network (C-RNN) at the abstract level and a multi-layer perception network (MLP) at the segment level are developed that further enhance the model performance. Additionally, an ablation study is also conducted to evaluate the contribution of individual component in the entire network to the model performance at different levels. Our proposed system is very competitive to the state-of-the-art systems and further improve F1 scores of the baseline by 1.0%, 2.8%, and 2.6% on the benchmark datasets PudMed 200K RCT, PudMed 20K RCT and NICTA-PIBOSO, respectively.

Scientific literature contains a considerable amount of information that provides an excellent opportunity for developing text mining methods to extract biomedical relationships. An important type of information is the relationship between singular nucleotide polymorphisms (SNP) and traits. In this paper, we present a BioBERT-GRU method to identify SNP- traits associations. Based on the evaluation of our method on the SNPPhenA dataset, it is concluded that this new method performs better than previous machine learning and deep learning based methods. BioBERT-GRU achieved the result a precision of 0.883, recall of 0.882 and F1-score of 0.881.

Bias and Variance are arguably the most important concepts in Machine Learning (ML). There is a lot of good ML literature that explains bias, variance and bias-variance trade-off. Also, often machine learning practitioners seem to believe that an increase in bias will surely increase variance and vice-versa. While this is probable, it is not always the case. This article is intended to explain bias and variance at an abstract level to ML enthusiasts with a belief that this knowledge will help them appreciate existing ML optimization techniques better. The job of any predictive machine learning algorithm is to estimate a function, as closely as possible, by looking at input and output of that function i.e. data.

Suppose an agent builds a policy that satisfactorily solves a decision problem; suppose further that some aspects of this policy are abstracted and used as starting point in a new, different decision problem. How can the agent accrue the benefits of the abstract policy in the new concrete problem? In this paper we propose a framework for simultaneous reinforcement learning, where the abstract policy helps start up the policy for the concrete problem, and both policies are refined through exploration. We report experiments that demonstrate that our framework is effective in speeding up policy construction for practical problems.

In problem domains where an informative heuristic evaluation function is not known or not easily computed, abstraction can be used to derive admissible heuristic values. Optimal path lengths in the abstracted problem are consistent heuristic estimates for the original problem. Pattern databases are the traditional method of creating such heuristics, but they exhaustively compute costs for all abstract states and are thus usually appropriate only when all instances share the same single goal state. Hierarchical heuristic search algorithms address these shortcomings by searching for paths in the abstract space on an as-needed basis. However, existing hierarchical algorithms search less efficiently than pattern database constructors: abstract nodes may be expanded many times during the course of a base-level search. We present a novel hierarchical heuristic search algorithm, called Switchback, that uses an alternating direction of search to avoid abstract node re-expansions. This algorithm is simple to implement and demonstrates superior performance to existing hierarchical heuristic search algorithms on several standard benchmarks.