{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,4]],"date-time":"2026-04-04T16:06:34Z","timestamp":1775318794869,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T00:00:00Z","timestamp":1753660800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["62271303"],"award-info":[{"award-number":["62271303"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["2021-01-07-00-10-E00121"],"award-info":[{"award-number":["2021-01-07-00-10-E00121"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["20ZR1423200"],"award-info":[{"award-number":["20ZR1423200"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Innovation Program of Shanghai Municipal Education Commission of China","award":["62271303"],"award-info":[{"award-number":["62271303"]}]},{"name":"Innovation Program of Shanghai Municipal Education Commission of China","award":["2021-01-07-00-10-E00121"],"award-info":[{"award-number":["2021-01-07-00-10-E00121"]}]},{"name":"Innovation Program of Shanghai Municipal Education Commission of China","award":["20ZR1423200"],"award-info":[{"award-number":["20ZR1423200"]}]},{"name":"Natural Science Foundation of Shanghai","award":["62271303"],"award-info":[{"award-number":["62271303"]}]},{"name":"Natural Science Foundation of Shanghai","award":["2021-01-07-00-10-E00121"],"award-info":[{"award-number":["2021-01-07-00-10-E00121"]}]},{"name":"Natural Science Foundation of Shanghai","award":["20ZR1423200"],"award-info":[{"award-number":["20ZR1423200"]}]}],"content-domain":{"domain":["www.mdpi.com"],"crossmark-restriction":true},"short-container-title":["Entropy"],"abstract":"<jats:p>This paper investigates the problem of computation offloading and resource allocation in an integrated space\u2013air\u2013sea network based on unmanned aerial vehicle (UAV) and low Earth orbit (LEO) satellites supporting Maritime Internet of Things (M-IoT) devices. Considering the complex, dynamic environment comprising M-IoT devices, UAVs and LEO satellites, traditional optimization methods encounter significant limitations due to non-convexity and the combinatorial explosion in possible solutions. A multi-agent deep deterministic policy gradient (MADDPG)-based optimization algorithm is proposed to address these challenges. This algorithm is designed to minimize the total system costs, balancing energy consumption and latency through partial task offloading within a cloud\u2013edge-device collaborative mobile edge computing (MEC) system. A comprehensive system model is proposed, with the problem formulated as a partially observable Markov decision process (POMDP) that integrates association control, power control, computing resource allocation, and task distribution. Each M-IoT device and UAV acts as an intelligent agent, collaboratively learning the optimal offloading strategies through a centralized training and decentralized execution framework inherent in the MADDPG. The numerical simulations validate the effectiveness of the proposed MADDPG-based approach, which demonstrates rapid convergence and significantly outperforms baseline methods, and indicate that the proposed MADDPG-based algorithm reduces the total system cost by 15\u201360% specifically.<\/jats:p>","DOI":"10.3390\/e27080803","type":"journal-article","created":{"date-parts":[[2025,7,28]],"date-time":"2025-07-28T10:51:14Z","timestamp":1753699874000},"page":"803","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["Research on Computation Offloading and Resource Allocation Strategy Based on MADDPG for Integrated Space\u2013Air\u2013Marine Network"],"prefix":"10.3390","volume":"27","author":[{"ORCID":"https:\/\/orcid.org\/0009-0008-3298-3845","authenticated-orcid":false,"given":"Haixiang","family":"Gao","sequence":"first","affiliation":[{"name":"College of Information Engineering, Shanghai Maritime University, Shanghai 200135, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qianlian","family":"Yu","sequence":"additional","affiliation":[{"name":"College of Information Engineering, Shanghai Maritime University, Shanghai 200135, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,28]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8910","DOI":"10.1109\/JIOT.2021.3056091","article-title":"Hybrid Satellite-Terrestrial Communication Networks for the Maritime Internet of Things: Key Technologies, Opportunities, and Challenges","volume":"8","author":"Wei","year":"2021","journal-title":"IEEE Internet Things J."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"188","DOI":"10.1109\/MWC.001.1900322","article-title":"Maritime Internet of Things: Challenges and Solutions","volume":"27","author":"Xia","year":"2020","journal-title":"IEEE Wirel. 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