{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,27]],"date-time":"2026-02-27T15:24:02Z","timestamp":1772205842063,"version":"3.50.1"},"reference-count":21,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2022,3,20]],"date-time":"2022-03-20T00:00:00Z","timestamp":1647734400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>An enhanced affine projection algorithm (APA) is proposed to improve the filter performance in aspects of convergence rate and steady-state estimation error, since the adjustment of the input-vector number can be an effective way to increase the convergence rate and to decrease the steady-state estimation error at the same time. In this proposed algorithm, the input-vector number of APA is adjusted reasonably at every iteration by comparing the averages of the accumulated squared errors. Although the conventional APA has the constraint that the input-vector number should be integer, the proposed APA relaxes that integer-constraint through a pseudo-fractional method. Since the input-vector number can be updated at every iteration more precisely based on the pseudo-fractional method, the filter performance of the proposed APA can be improved. According to our simulation results, it is demonstrated that the proposed APA has a smaller steady-state estimation error compared to the existing APA-type filters in various scenarios.<\/jats:p>","DOI":"10.3390\/e24030431","type":"journal-article","created":{"date-parts":[[2022,3,20]],"date-time":"2022-03-20T21:26:22Z","timestamp":1647811582000},"page":"431","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["An Enhanced Affine Projection Algorithm Based on the Adjustment of Input-Vector Number"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3765-6009","authenticated-orcid":false,"given":"Jaewook","family":"Shin","sequence":"first","affiliation":[{"name":"Department of Electronic Engineering, Kumoh National Institute of Technology, Gumi 39177, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2542-0234","authenticated-orcid":false,"given":"Jeesu","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Cogno-Mechatronics Engineering, Pusan National University, Busan 46241, Korea"},{"name":"Department of Optics and Mechatronics Engineering, Pusan National University, Busan 46241, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9629-7413","authenticated-orcid":false,"given":"Tae-Kyoung","family":"Kim","sequence":"additional","affiliation":[{"name":"Department of Electronic Engineering, Gachon University, Seongnam 13120, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1025-3784","authenticated-orcid":false,"given":"Jinwoo","family":"Yoo","sequence":"additional","affiliation":[{"name":"Department of Automobile and IT Convergence, Kookmin University, Seoul 02707, Korea"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,3,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Zhang, R., and Zhao, H. 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