Judul: Customer and Loyalty Satisfaction of Warung Pinus Coffee Shop in Subang Regency
Abstrak: Warung Pinus merupakan salah satu usaha Kedai Kopi yang bersaing di industri restoran Kabupaten Subang. Perkembangan kedai kopi di Kabupaten Subang yang meningkat setiap tahunnya mengakibatkan tingkat persaingan semakin tinggi. Cara yang dapat dilakukan oleh Kedai Kopi Warung Pinus untuk dapat mempertahankan pelanggannya yaitu dengan memberikan produk dan layanan terbaik kepada pelanggan. Penelitian ini bertujuan untuk mengetahui karakteristik, tingkat kepuasan, tingkat loyalitas, serta pengaruh kepuasan terhadap loyalitas pelanggan Kedai Kopi Warung Pinus di Kabupaten Subang. Penelitian ini menggunakan analisis deskriptif, Customer Satisfaction Index (CSI), Important Performance Analysis (IPA), dan Analisis Loyalitas. Jumlah responden dalam penelitian ini adalah 100 responden. Karakteristik pelanggan Kedai Kopi Warung Pinus sebagian besar merupakan generasi milenial dengan rentang usia terbanyak terdapat pada 16-24 tahun. Berdasarkan hasil analisis CSI, tingkat kepuasan pelanggan terhadap atribut Kedai Kopi Warung Pinus adalah 79,74 persen. Sedangkan hasil dari IPA menunjukkan bahwa ketersediaan tampilan menu, kesigapan dalam merespon pertanyaan, dan kesigapan pramusaji saat dipanggil merupakan prioritas utama dalam perbaikan kinerja atribut untuk meningkatkan kepuasan pelanggan. Dan tingkat loyalitas pelanggan terhadap Kedai Kopi Warung Pinus menunjukkan bahwa pelanggan dengan kategori commited buyer cukup rendah dengan nilai 15 persen, hal tersebut membuktikan bahwa pelanggan Kedai Kopi Warung Pinus belum termasuk kedalam pelanggan yang loyal. Hasil Rank Spearman menunjukan bahwa pelanggan Kedai Kopi Warung Pinus yang merasa puas belum tentu loyal.
Keyword: CSI, IPA, Kedai Kopi Warung Pinus, Kepuasan Pelanggan, Loyalitas Pelanggan

Judul: Analisis Kepuasan dan Loyalitas Pelanggan Di Warung Kopi Rawa Sakti, Banda Aceh
Abstrak: Rawa Sakti Coffeeshop is one of coffeshops in Banda Aceh that offers only Aceh coffee with a various menus. Lots of coffeshops in Banda Aceh increased business competition and affects the number of costumer visiting Rawa Sakti Coffeeshop. The purpose of this research was to identify consumer characteristics, analyze the level of custumer satisfaction, and measuring consumer loyalty level of Rawa Sakti Coffeeshop. The method used in this research was descriptive analysis, Customer Satisfaction Index (CSI), Importance Performance Analysis (IPA), and loyalty pyramid. Based on the research, it is known that the majority of consumers who visit Rawa Sakti are men, based in Banda Aceh, aged 17-24 years, educated as a highschool, unmarried, worked as a university student with income between Rp500 001- Rp1 000 000. Based on the analysis, the level of Customer Satisfaction Index (CSI) of Rawa Sakti Coffeeshop is 79.74 percent. Based on loyalty pyramid, consumer of Rawa Sakti Coffeeshop is dominated by habitual buyer is 39,80 percent, thus showed that the level of consumer loyalty is still relatively low and the form of the loyalty pyramid is not inverted triangular
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model