{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,4,11]],"date-time":"2025-04-11T10:29:50Z","timestamp":1744367390529,"version":"3.37.3"},"reference-count":38,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2023,11,30]],"date-time":"2023-11-30T00:00:00Z","timestamp":1701302400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"James M. Cox Foundation and Cox Enterprises, Inc.","award":["cox-emory2019"]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"Spatial navigation patterns in indoor space usage can reveal important cues about the cognitive health of participants. In this work, we present a low-cost, scalable, open-source edge computing system using Bluetooth low energy (BLE) beacons for tracking indoor movements in a large, 1700 m2 facility used to carry out therapeutic activities for participants with mild cognitive impairment (MCI). The facility is instrumented with 39 edge computing systems, along with an on-premise fog server. The participants carry a BLE beacon, in which BLE signals are received and analyzed by the edge computing systems. Edge computing systems are sparsely distributed in the wide, complex indoor space, challenging the standard trilateration technique for localizing subjects, which assumes a dense installation of BLE beacons. We propose a graph trilateration approach that considers the temporal density of hits from the BLE beacon to surrounding edge devices to handle the inconsistent coverage of edge devices. This proposed method helps us tackle the varying signal strength, which leads to intermittent detection of beacons. The proposed method can pinpoint the positions of multiple participants with an average error of 4.4 m and over 85% accuracy in region-level localization across the entire study area. Our experimental results, evaluated in a clinical environment, suggest that an ordinary medical facility can be transformed into a smart space that enables automatic assessment of individuals\u2019 movements, which may reflect health status or response to treatment.<\/jats:p>","DOI":"10.3390\/s23239517","type":"journal-article","created":{"date-parts":[[2023,11,30]],"date-time":"2023-11-30T14:37:54Z","timestamp":1701355074000},"page":"9517","source":"Crossref","is-referenced-by-count":6,"title":["Graph Trilateration for Indoor Localization in Sparsely Distributed Edge Computing Devices in Complex Environments Using Bluetooth Technology"],"prefix":"10.3390","volume":"23","author":[{"given":"Yashar","family":"Kiarashi","sequence":"first","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3676-5027","authenticated-orcid":false,"given":"Soheil","family":"Saghafi","sequence":"additional","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-1799-8247","authenticated-orcid":false,"given":"Barun","family":"Das","sequence":"additional","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"given":"Chaitra","family":"Hegde","sequence":"additional","affiliation":[{"name":"School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-0314-2843","authenticated-orcid":false,"given":"Venkata Siva Krishna","family":"Madala","sequence":"additional","affiliation":[{"name":"School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"given":"ArjunSinh","family":"Nakum","sequence":"additional","affiliation":[{"name":"School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"given":"Ratan","family":"Singh","sequence":"additional","affiliation":[{"name":"School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2092-940X","authenticated-orcid":false,"given":"Robert","family":"Tweedy","sequence":"additional","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"given":"Matthew","family":"Doiron","sequence":"additional","affiliation":[{"name":"Department of Neurology, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"given":"Amy D.","family":"Rodriguez","sequence":"additional","affiliation":[{"name":"Department of Neurology, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"given":"Allan I.","family":"Levey","sequence":"additional","affiliation":[{"name":"Department of Neurology, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]},{"given":"Gari D.","family":"Clifford","sequence":"additional","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"},{"name":"Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA 30322, USA"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5693-3278","authenticated-orcid":false,"given":"Hyeokhyen","family":"Kwon","sequence":"additional","affiliation":[{"name":"Department of Biomedical Informatics, School of Medicine, Emory University, Atlanta, GA 30322, USA"}]}],"member":"1968","published-online":{"date-parts":[[2023,11,30]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"3160","DOI":"10.1038\/s41598-022-06899-w","article-title":"Machine learning detects altered spatial navigation features in outdoor behaviour of Alzheimer\u2019s disease patients","volume":"12","author":"Ghosh","year":"2022","journal-title":"Sci. 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