<![CDATA[Abstract-Implementation Centainty Factor Algorthm and UML modelling in designing the application of the diagnosis of Gastritis disease. Ignorance of gastritis disease and the limitation of handling the disease is often experienced by teenagers. Therefore we need for action / treatment quickly to prevent gastritis disease. Gastritis is an inflammatory process in the mucosal layer and gastric submucosa as a mechanism of mucosal protection when there is accumulation of bacteria or other irritant substances. The inflammatory process may be mild (Dyspepsia), moderate (Gerd) and acute Gastritis. Expert system requires a method or rule in solving the problem of gastritis disease is by certainty factor method. The method certainty factor (CF) can defined the size of certainty by the fac or rulest, to describe the level of expert confidence to the problem at hand. Therefore in this study developed expert system that can be accessed through mobile devices such as android phone. The delivery of information was done using a mobile device, so it can be concluded that the research is implemented into the android application. So with the manufacture of expert systems to diagnose gastritis disease can help people, especially in adolescence to know the problems and severity such as mild, chronic gastritis symptoms. Keywords-Expert System, Certainty Factor, Diagnosis of Gastritis Disease Referensi : [1] IDI, “Panduan Praktik Klinis Bagi Dokter di Fasilitas Pelayanan Kesehatan Primer,†Menteri Kesehatan Republik Indonesia., pp. 162, 364, 2017. [2] D. Wahyu, Supono, and N. Hidayah, “Pola Makan Sehari-hari Penderita Gastritis,†J. Inf. Kesehat. Indones., vol. 1, no. 77, pp. 17– 24, 2015. [3] N. A. Ritonga, “SISTEM PAKAR MENDIAGNOSA PENYAKIT LAMBUNG,†Pelita Inform. Budi Darma, vol. V, no. November, pp. 157–161, 2013. [4] H. T. Sihotang, “Sistem pakar untuk mendiagnosa penyakit pada tanaman jagung dengan metode bayes,†vol. 3, no. 1, 2018. [5] B. Susetyo, I. Nurhayati, I. Purnahayu, and P. Eosina, “Model Evaluasi Kinerja SDM Geospasial Menggunakan Metode CPI dan CPD Berbasis WebGIS,†vol. 2020, 2017. [6] F. Akbar, S.setiaji, R. Ishak, D. Saputra, and B. Masruri, “Rancang Bangun Sistem Informasi Karang Taruna Menggunakan Metode Waterfall,†Khatulistiwa Inform., vol. VIII, no. 1, pp. 7–12, 2020,[Online]. Available: www.bsi.ac.id. [7] N. Sari and B. Sembiring, “BAKTERI SALMONELLA DALAM TUBUH MANUSIA MENGGUNAKAN METODE CERTAINTY FACTOR,†pp. 394–399, 2014. [8] M. Zunaidi, M. Rasyid, and I. Zulkarnain, “Penerapan Metode Certainty Factor dalam Teknik Photography untuk Menentukan Settingan Kamera DSLR yang Menghasilkan Gambar Terbaik,†J. Ilm. Saintikom, vol. 14, p. 186, 2015. [9] J. A. Widians and A. Utomo, “SISTEM PAKAR DIAGNOSA DYSPEPSIA DENGAN CERTAINTY FACTOR,†pp. 6–8, 2015. [10] H. A. Hidayat and G. Gumilang, “Sistem Pakar Diagnosis Penyakit Yang Disebabkan Oleh Rokok Dengan Metode Forward Chaining,†Jutekin, vol. 3, no. 1, pp. 27–36, 2017.]]>
