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1. Assigning Credit with Partial Reward Decoupling in Multi-Agent Proximal Policy Optimization

Author

Kapoor, Aditya, Freed, Benjamin, Choset, Howie, and Schneider, Jeff

Subjects
Computer Science - Multiagent Systems, Computer Science - Artificial Intelligence, Computer Science - Machine Learning, Computer Science - Robotics
Abstract

Multi-agent proximal policy optimization (MAPPO) has recently demonstrated state-of-the-art performance on challenging multi-agent reinforcement learning tasks. However, MAPPO still struggles with the credit assignment problem, wherein the sheer difficulty in ascribing credit to individual agents' actions scales poorly with team size. In this paper, we propose a multi-agent reinforcement learning algorithm that adapts recent developments in credit assignment to improve upon MAPPO. Our approach leverages partial reward decoupling (PRD), which uses a learned attention mechanism to estimate which of a particular agent's teammates are relevant to its learning updates. We use this estimate to dynamically decompose large groups of agents into smaller, more manageable subgroups. We empirically demonstrate that our approach, PRD-MAPPO, decouples agents from teammates that do not influence their expected future reward, thereby streamlining credit assignment. We additionally show that PRD-MAPPO yields significantly higher data efficiency and asymptotic performance compared to both MAPPO and other state-of-the-art methods across several multi-agent tasks, including StarCraft II. Finally, we propose a version of PRD-MAPPO that is applicable to \textit{shared} reward settings, where PRD was previously not applicable, and empirically show that this also leads to performance improvements over MAPPO., Comment: 20 pages, 5 figures, 12 tables, Reinforcement Learning Journal and Reinforcement Learning Conference 2024

Published
2024

3. Defining Echocardiographic Degrees of Right Heart Size and Function in Pulmonary Vascular Disease From the PVDOMICS Study

Author

Mukherjee, Monica, Mathai, Stephen C., Jellis, Christine, Freed, Benjamin H., Yanek, Lisa R., Agoglia, Hannah, Chiu, Caitlin, Jani, Vivek P., Simpson, Catherine E., Brittain, Evan L., Tang, W.H. Wilson, Park, Margaret M., Hemnes, Anna R., Rosenzweig, Erika B., Rischard, Franz P., Frantz, Robert P., Hassoun, Paul M., Beck, Gerald, Hill, Nicholas S., Erzurum, Serpil, Thomas, James D., Kwon, Deborah, Leopold, Jane A., Horn, Evelyn M., and Kim, Jiwon

Published
2024
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4. Learning Cooperative Multi-Agent Policies with Partial Reward Decoupling

Author

Freed, Benjamin, Kapoor, Aditya, Abraham, Ian, Schneider, Jeff, and Choset, Howie

Subjects
Computer Science - Machine Learning, Computer Science - Artificial Intelligence, Computer Science - Robotics
Abstract

One of the preeminent obstacles to scaling multi-agent reinforcement learning to large numbers of agents is assigning credit to individual agents' actions. In this paper, we address this credit assignment problem with an approach that we call \textit{partial reward decoupling} (PRD), which attempts to decompose large cooperative multi-agent RL problems into decoupled subproblems involving subsets of agents, thereby simplifying credit assignment. We empirically demonstrate that decomposing the RL problem using PRD in an actor-critic algorithm results in lower variance policy gradient estimates, which improves data efficiency, learning stability, and asymptotic performance across a wide array of multi-agent RL tasks, compared to various other actor-critic approaches. Additionally, we relate our approach to counterfactual multi-agent policy gradient (COMA), a state-of-the-art MARL algorithm, and empirically show that our approach outperforms COMA by making better use of information in agents' reward streams, and by enabling recent advances in advantage estimation to be used., Comment: in IEEE Robotics and Automation Letters

Published
2021
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5. Association of Pericardial Fat with Cardiac Structure, Function, and Mechanics: The Multi-Ethnic Study of Atherosclerosis

Author

Min, Jeff, Putt, Mary E, Yang, Wei, Bertoni, Alain G, Ding, Jingzhong, Lima, Joao AC, Allison, Matthew A, Barr, R Graham, Al-Naamani, Nadine, Patel, Ravi B, Beussink-Nelson, Lauren, Kawut, Steven M, Shah, Sanjiv J, and Freed, Benjamin H

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Aging, Atherosclerosis, Clinical Research, Heart Disease, Cardiovascular, Aetiology, 2.1 Biological and endogenous factors, Adipose Tissue, Adiposity, Adult, Cardiomyopathies, Humans, Pericardium, Pericardial fat, Echocardiography, Myocardial strain analysis, Early heart failure, Cardiorespiratory Medicine and Haematology, Cardiovascular System & Hematology, Cardiovascular medicine and haematology
Abstract

BackgroundPericardial fat has been associated with adverse cardiovascular outcomes through adiposity-associated inflammation and insulin resistance, which in turn are linked to cardiac dysfunction. We sought to evaluate the association between pericardial fat volume and cardiac structure and function in adults without baseline cardiovascular disease.MethodsWe analyzed data from the Multi-Ethnic Study of Atherosclerosis. Linear regression was used to examine the association between pericardial fat volume (by cardiac computed tomography during exam 1, 2000-2002) and cardiac function by echocardiography, six-minute walk distance (6MWD), and symptom severity as assessed using the Kansas City Cardiomyopathy Questionnaire-12 (exam 6, 2016-18).ResultsAmong 3,032 participants, each 1 SD (39.3 cm3) increase in pericardial fat volume was associated with lower (worse) absolute left atrial reservoir strain (β = -0.98%; 95% CI, -1.29, -0.68; P

Published
2022

19. MR and CT Imaging for the Evaluation of Pulmonary Hypertension

Author

Freed, Benjamin H, Collins, Jeremy D, François, Christopher J, Barker, Alex J, Cuttica, Michael J, Chesler, Naomi C, Markl, Michael, and Shah, Sanjiv J

Subjects
Biomedical and Clinical Sciences, Cardiovascular Medicine and Haematology, Clinical Sciences, Biomedical Imaging, Lung, Clinical Research, Bioengineering, 4.2 Evaluation of markers and technologies, Detection, screening and diagnosis, Arterial Pressure, Computed Tomography Angiography, Humans, Hypertension, Pulmonary, Magnetic Resonance Imaging, Perfusion Imaging, Predictive Value of Tests, Prognosis, Pulmonary Artery, Pulmonary Circulation, Ventricular Function, Left, Ventricular Function, Right, anatomy, computed tomography, magnetic resonance imaging, physiology, pulmonary hypertension, pulmonary vasculature, right ventricle, Cardiorespiratory Medicine and Haematology, Cardiovascular System & Hematology, Cardiovascular medicine and haematology, Clinical sciences
Abstract

Imaging plays a central role in the diagnosis and management of all forms of pulmonary hypertension (PH). Although Doppler echocardiography is essential for the evaluation of PH, its ability to optimally evaluate the right ventricle and pulmonary vasculature is limited by its 2-dimensional planar capabilities. Magnetic resonance and computed tomography are capable of determining the etiology and pathophysiology of PH, and can be very useful in the management of these patients. Exciting new techniques such as right ventricle tissue characterization with T1 mapping, 4-dimensional flow of the right ventricle and pulmonary arteries, and computed tomography lung perfusion imaging are paving the way for a new era of imaging in PH. These imaging modalities complement echocardiography and invasive hemodynamic testing and may be useful as surrogate endpoints for early phase PH clinical trials. Here we discuss the role of magnetic resonance imaging and computed tomography in the diagnosis and management of PH, including current uses and novel research applications, and we discuss the role of value-based imaging in PH.

Published
2016

20. Normative Values of Echocardiographic Chamber Size and Function in Older Healthy Adults: The Multi-Ethnic Study of Atherosclerosis

Author

Mukherjee, Monica, primary, Strom, Jordan B., additional, Afilalo, Jonathan, additional, Hu, Mo, additional, Beussink-Nelson, Lauren, additional, Kim, Jiwon, additional, Addetia, Karima, additional, Bertoni, Alain G, additional, Gottdiener, John S., additional, Michos, Erin D., additional, Gardiin, Julius M., additional, Shah, Sanjiv J, additional, and Freed, Benjamin H, additional

Published
2023
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24. Characteristics of Right Ventricular to Pulmonary Arterial Coupling and Association With Functional Status Among Older Aged Adults from the Multi-Ethnic Study of Atherosclerosis

Author

Mukherjee, Monica, primary, Ogunmoroti, Oluseye, additional, Jani, Vivek, additional, Kapoor, Karan, additional, Beussink-Nelson, Lauren, additional, Freed, Benjamin H., additional, Hays, Allison G., additional, Shah, Sanjiv J., additional, and Michos, Erin D., additional

Published
2023
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29. Convolution Neural Network Algorithm for Shockable Arrhythmia Classification Within a Digitally Connected Automated External Defibrillator

Author

Shen, Christine P., primary, Freed, Benjamin C., additional, Walter, David P., additional, Perry, James C., additional, Barakat, Amr F., additional, Elashery, Ahmad Ramy A., additional, Shah, Kevin S., additional, Kutty, Shelby, additional, McGillion, Michael, additional, Ng, Fu Siong, additional, Khedraki, Rola, additional, Nayak, Keshav R., additional, Rogers, John D., additional, and Bhavnani, Sanjeev P., additional

Published
2023
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48. Contributors

Author

Abbas, Amr E., primary, Abdelmoneim, Sahar S., additional, Abraham, Theodore, additional, Acquatella, Harry, additional, Adams, David B., additional, Addetia, Karima, additional, Afilalo, Jonathan, additional, Agarwal, Vikram, additional, Agmon, Yoram, additional, Ahmed, Mohamed, additional, Alviar, Carlos, additional, Anderson, Bonita, additional, Argulian, Edgar, additional, Asch, Federico M., additional, Aurigemma, Gerard P., additional, Axsom, Kelly, additional, Badano, Luigi P., additional, Balakrishnan, Revathi, additional, Banerji, Sourin, additional, Bangalore, Sripal, additional, Bansal, Manish, additional, Bartel, Thomas, additional, Baumann, Rebecca Lynn, additional, Baumgartner, Helmut, additional, Beigel, Roy, additional, Belcik, J. Todd, additional, Belohlavek, Marek, additional, Benenstein, Ricardo, additional, Berkowitz, Eric, additional, Bhave, Nicole M., additional, Biviano, Angelo, additional, Blank, Nimrod, additional, Bonow, Robert O., additional, Burstow, Darryl J., additional, Byrd, Benjamin, additional, Carerj, Scipione, additional, Carroll, John D., additional, Chadderdon, Scott, additional, Chaliki, Hari P., additional, Chan, Kwan-Leung, additional, Chaudhry, Farooq A., additional, Chidsey, Geoff, additional, Churzidse, Sofia, additional, Coll, Blai, additional, Cui, Vivian W., additional, Cusma-Picconne, Maurizio, additional, Dahou, Abdellaziz, additional, Dal-Bianco, Jacob P., additional, Daneshvar, Daniel A., additional, Daubert, Melissa A., additional, Davidoff, Ravin, additional, DeCara, Jeanne M., additional, Delgado-Montero, Antonia, additional, Dellefave-Castillo, Lisa, additional, Desai, Ankit A., additional, DeSouza, Kavit A., additional, Doherty, Bryan, additional, Donnino, Robert, additional, Douglas, Pamela S., additional, Dudzinski, David M., additional, Dulgheru, Raluca, additional, Dumesnil, Jean G., additional, Elkayam, Uri, additional, Erbel, Raimund, additional, Erenberg, Francine, additional, Evangelista, Arturo A., additional, Feinstein, Steven B., additional, Ferreira, Beatriz, additional, Foster, Elyse, additional, Freed, Benjamin H., additional, Gardin, Julius M., additional, Gill, Edward A., additional, Gillam, Linda, additional, Giovannone, Steven, additional, Goldberger, Mark, additional, Goldstein, Steven A., additional, Gorcsan, John, additional, Gorla, Riccardo, additional, Grapsa, Julia, additional, Grawe, Erin S., additional, Gruner, Christiane, additional, Gupta, Pooja, additional, Gurudevan, Swaminatha, additional, Hahn, Rebecca T., additional, Han, Yuchi, additional, Hellawell, Jennifer L., additional, Hillier, Samuel D., additional, Hoit, Brian D., additional, Humes, Richard, additional, Jagadeesan, Vikrant, additional, Jain, Sonia, additional, Janosi, Alexander, additional, Kahn, Peter A., additional, Kaul, Sanjiv, additional, Khandheria, Bijoy K., additional, Kim, Gene H., additional, Kim, Michael S., additional, Kimura, Bruce J., additional, King, Mary Etta, additional, Kireyev, Dmitry, additional, Kirkpatrick, James N., additional, Klein, Allan L., additional, Kohli, Payal, additional, Korcarz, Claudia E., additional, Kort, Smadar, additional, Kosmala, Wojciech, additional, Koulogiannis, Konstantinos, additional, Koutsogeorgis, Ilias, additional, Kremkau, Frederick W., additional, Krieger, Eric V., additional, Kronzon, Itzhak, additional, Kutnick, Richard T., additional, Lai, Wyman, additional, Lambert, Stephane, additional, Lancellotti, Patrizio, additional, Lang, Roberto M., additional, Lee, Alex Pui-Wai, additional, Lee, Ming Sum, additional, Lerakis, Stamatios, additional, Lessick, Jonathan, additional, Lester, Steven J., additional, Leung, Steve W., additional, LeVen, Florent, additional, Levine, Robert A., additional, Li, Qin, additional, Lima, Fabio, additional, Lindner, Jonathan R., additional, Lopez, Leo, additional, Magne, Julien, additional, Mahjoub, Haifa, additional, Mangion, Judy R., additional, Mankad, Sunil V., additional, Maragiannis, Dimitrios, additional, Marcoff, Leo, additional, Martin, Randolph P., additional, Marwick, Thomas H., additional, Massabuau, Pierre, additional, Mathur, Moses, additional, McCully, Robert, additional, McGee, Edwin C., additional, McNally, Elizabeth, additional, Mehta, Sudhir Ken, additional, Mendelson, Todd, additional, Mikati, Issam A., additional, Modesto, Karen, additional, Monaghan, Mark, additional, Mookadam, Farouk, additional, Moonen, Marie, additional, Mukherjee, Monica, additional, Müller, Silvana, additional, Mulvagh, Sharon L., additional, Muraru, Denisa, additional, Murtagh, Gillian, additional, Nagueh, Sherif F., additional, Naqvi, Tasneem Z., additional, Nathan, Sandeep, additional, Negishi, Kazuaki, additional, Nihoyannopoulos, Petros, additional, Nkomo, Vuyisile T., additional, Oechslin, Erwin, additional, Olson, Joan, additional, Palios, John, additional, Parikh, Gaurav, additional, Patel, Amit R., additional, Patel, Amit V., additional, Patel, Aneet, additional, Patel, Anupa, additional, Paterick, Timothy E., additional, Payvandi, Laila A., additional, Pedrizzetti, Gianni, additional, Pellikka, Patricia A., additional, Perk, Gila, additional, Peters, Ferande, additional, Phelan, Dermot, additional, Pibarot, Philippe, additional, Picard, Michael H., additional, Plana, Juan Carlos, additional, Popovic, Zoran B., additional, Porter, Thomas, additional, Pun, Shawn C., additional, Qasim, Atif N., additional, Quader, Nishath, additional, Quinones, Miguel A., additional, Rahko, Peter S., additional, Rakowski, Harry, additional, Rao, Rajeev V., additional, Reiken, Joseph, additional, Reisner, Shimon A., additional, Retzer, Elizabeth M., additional, Rigolin, Vera H., additional, Roberson, David A., additional, Rodgers, Keith, additional, Roper, Damian, additional, Rosenhek, Raphael, additional, Ross, Eleanor, additional, Roy, R. Raina, additional, Ruberg, Frederick L., additional, Rudski, Lawrence G., additional, Ruiz, Carlos, additional, Salcedo, Ernesto E., additional, Sanborn, Danita M. Yoerger, additional, Sardana, Vrinda, additional, Saric, Muhamed, additional, Schiller, Nelson B., additional, Schinkel, Arend F.L., additional, Schwartzenberg, Shmuel S., additional, Sengupta, Partho P., additional, Shah, Pravin M., additional, Shanewise, Jack S., additional, Shernan, Stanton K., additional, Shih, Jeffrey A., additional, Siegel, Robert J., additional, Siriwardena, Maithri, additional, Siu, Samuel, additional, Solomon, Scott D., additional, Sorrell, Vincent L., additional, Spencer, Kirk T., additional, Spiegel, Denise, additional, John Sutton, Martin St., additional, Stein, James H., additional, Stergiopoulos, Kathleen, additional, Supariwala, Azhar A., additional, Szmitko, Paul E., additional, Tajouri, Tanya H., additional, Takeuchi, Masaaki, additional, Tan, Timothy C., additional, Thomas, James D., additional, Tighe, Dennis A., additional, Todaro, Maria C., additional, Tower-Rader, Albree, additional, Tsang, Michael Y.C., additional, Tsang, Teresa S.M., additional, Tsang, Wendy, additional, Tunick, Paul A., additional, Vignon, Philippe, additional, Wafsy, Meagan M., additional, Wald, Rachel, additional, Ward, R. Parker, additional, Watanabe, Nozomi, additional, Wei, Kevin, additional, Weissman, Neil J., additional, Welsch, Mariko, additional, Wiegers, Susan, additional, Williams, Lynne, additional, Woo, Anna, additional, Wuttichaipradit, Chanwit, additional, Xie, Feng, additional, Yingchoncharoen, Teerapat, additional, Yu, Cheuk-Man, additional, Yu, Zoe, additional, Zhao, Qiong, additional, Zito, Concetta, additional, and Zoghbi, William A., additional

Published
2016
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