Rosen-Zvi, Michal
MAMMAL -- Molecular Aligned Multi-Modal Architecture and Language
Shoshan, Yoel, Raboh, Moshiko, Ozery-Flato, Michal, Ratner, Vadim, Golts, Alex, Weber, Jeffrey K., Barkan, Ella, Rabinovici-Cohen, Simona, Polaczek, Sagi, Amos, Ido, Shapira, Ben, Hazan, Liam, Ninio, Matan, Ravid, Sivan, Danziger, Michael M., Morrone, Joseph A., Suryanarayanan, Parthasarathy, Rosen-Zvi, Michal, Hexter, Efrat
Drug discovery typically consists of multiple steps, including identifying a target protein key to a disease's etiology, validating that interacting with this target could prevent symptoms or cure the disease, discovering a small molecule or biologic therapeutic to interact with it, and optimizing the candidate molecule through a complex landscape of required properties. Drug discovery related tasks often involve prediction and generation while considering multiple entities that potentially interact, which poses a challenge for typical AI models. For this purpose we present MAMMAL - Molecular Aligned Multi-Modal Architecture and Language - a method that we applied to create a versatile multi-task multi-align foundation model that learns from large-scale biological datasets (2 billion samples) across diverse modalities, including proteins, small molecules, and genes. We introduce a prompt syntax that supports a wide range of classification, regression, and generation tasks. It allows combining different modalities and entity types as inputs and/or outputs. Our model handles combinations of tokens and scalars and enables the generation of small molecules and proteins, property prediction, and transcriptomic lab test predictions. We evaluated the model on 11 diverse downstream tasks spanning different steps within a typical drug discovery pipeline, where it reaches new SOTA in 9 tasks and is comparable to SOTA in 2 tasks. This performance is achieved while using a unified architecture serving all tasks, in contrast to the original SOTA performance achieved using tailored architectures. The model code and pretrained weights are publicly available at https://github.com/BiomedSciAI/biomed-multi-alignment and https://huggingface.co/ibm/biomed.omics.bl.sm.ma-ted-458m.
Novel Uncertainty Framework for Deep Learning Ensembles
Kachman, Tal, Moshkovitz, Michal, Rosen-Zvi, Michal
Deep learning (DL) algorithms have successfully solved real-world classification problems from a variety of fields, including recognizing handwritten digits and identifying the presence of key diagnostic features in medical images [18, 16]. A typical classification challenge for a DL algorithm consists of training the algorithm on an example data set, then using a separate set of test data to evaluate its performance. The aim is to provide answers that are as accurate as possible, as measured by the true positive rate (TPR) and the true negative rate (TNR). Many DL classifiers, particularly those using a softmax function in the very last layer, yield a continuous score, h; A step function is used to map this continuous score to each of the possible categories that are being classified. TPR and TNR scores are then generated for each separate variable that is being predicted by setting a threshold parameter that is applied when mapping h to the decision. Values above this threshold are mapped to positive predictions, while values below it are mapped to negative predictions. The ROC curve is then generated from these pairs of TPR/TPN scores.
The Author-Topic Model for Authors and Documents
Rosen-Zvi, Michal, Griffiths, Thomas, Steyvers, Mark, Smyth, Padhraic
We introduce the author-topic model, a generative model for documents that extends Latent Dirichlet Allocation (LDA; Blei, Ng, & Jordan, 2003) to include authorship information. Each author is associated with a multinomial distribution over topics and each topic is associated with a multinomial distribution over words. A document with multiple authors is modeled as a distribution over topics that is a mixture of the distributions associated with the authors. We apply the model to a collection of 1,700 NIPS conference papers and 160,000 CiteSeer abstracts. Exact inference is intractable for these datasets and we use Gibbs sampling to estimate the topic and author distributions. We compare the performance with two other generative models for documents, which are special cases of the author-topic model: LDA (a topic model) and a simple author model in which each author is associated with a distribution over words rather than a distribution over topics. We show topics recovered by the author-topic model, and demonstrate applications to computing similarity between authors and entropy of author output.
The DLR Hierarchy of Approximate Inference
Rosen-Zvi, Michal, Jordan, Michael I., Yuille, Alan
We propose a hierarchy for approximate inference based on the Dobrushin, Lanford, Ruelle (DLR) equations. This hierarchy includes existing algorithms, such as belief propagation, and also motivates novel algorithms such as factorized neighbors (FN) algorithms and variants of mean field (MF) algorithms. In particular, we show that extrema of the Bethe free energy correspond to approximate solutions of the DLR equations. In addition, we demonstrate a close connection between these approximate algorithms and Gibbs sampling. Finally, we compare and contrast various of the algorithms in the DLR hierarchy on spin-glass problems. The experiments show that algorithms higher up in the hierarchy give more accurate results when they converge but tend to be less stable.
Latent Topic Models for Hypertext
Gruber, Amit, Rosen-Zvi, Michal, Weiss, Yair
Latent topic models have been successfully applied as an unsupervised topic discovery technique in large document collections. With the proliferation of hypertext document collection such as the Internet, there has also been great interest in extending these approaches to hypertext [6, 9]. These approaches typically model links in an analogous fashion to how they model words - the document-link co-occurrence matrix is modeled in the same way that the document-word co-occurrence matrix is modeled in standard topic models. In this paper we present a probabilistic generative model for hypertext document collections that explicitly models the generation of links. Specifically, links from a word w to a document d depend directly on how frequent the topic of w is in d, in addition to the in-degree of d. We show how to perform EM learning on this model efficiently. By not modeling links as analogous to words, we end up using far fewer free parameters and obtain better link prediction results.