Sustainable tourism promotion through mobile gamification and reward systems for Chiang Mai Old Town, Thailand. - Orawit Thinnukool; Rattaphol Phrommas; Nop Kongdee; Manissaward Jintapitak; Khanithep Pitupumnak; Tatiyaporn Jarumaneerat; Pattaraporn Khuwuthyakorn (Frontiers Comput. Sci., 2025)