Judul: Customer Attitude and Satisfaction by Online Application for Ready-to-Eat Food Delivery Service in Jabodetabek
Abstrak: Pandemi Covid-19 membuat masyarakat harus lebih berusaha untuk bertahan hidup. Khususnya warga sekitar Jabodetabek yang terdampak PSBB mengakibatkan mobilisasi masyarakat menjadi terbatas dan aplikasi daring membantu pelanggan untuk membeli makanan. Tujuan dari penelitian ini adalah menganalisis proses keputusan pembelian, sikap dan kepuasan pelanggan serta menguji perbedaan secara nyata pada sikap dan kepuasan pelanggan. Analisis deskriptif digunakan untuk proses keputusan pembelian pelanggan. Analisis Multiatribut Fishbein digunakan untuk menganalisis sikap pelanggan dan kepuasan pelanggan pada penelitian ini menggunakan analisis CSI. Serta penggunaan uji beda nonparametik Mann-Whitney. Hasil penelitian menunjukkan bahwa terdapat lima proses keputusan pembelian, nilai sikap terhadap pelanggan aplikasi GrabFood lebih besar dibandingkan GoFood dengan poin 193,88 dan 193,86. Diperoleh sikap dan kepuasan pelanggan GoFood dan GrabFood tidak berbeda secara nyata, serta pelanggan dianggap puas dengan nilai CSI GoFood dan GrabFood sebesar 79,24% dan 78,16%., The Covid-19 pandemic has forced people to do more to survive. In particular, residents around Jabodetabek who were affected by the PSBB resulted in limited community mobilization and online applications helping customers to buy food. The purpose of this study are to analyze the purchasing decision process, attitudes and customer satisfaction and to test whether there is a significant difference in attitudes and customer satisfaction. Descriptive analysis tools are used for the customer's purchasing decision process. Fishbein Multiattribute Analysis is used to analyze customer attitudes and customer satisfaction in this study using CSI analysis. And the use of the Mann-Whitney nonparametric difference test. The results show that there are five purchasing decision processes, the attitude value towards GrabFood application customers is greater than GoFood with 193.88 and 193.86 points. The attitudes and satisfaction of GoFood and GrabFood customers were not significantly different, and customers were considered satisfied with the CSI GoFood and GrabFood values of 79.24% and 78.16%, respectively.
Keyword: Customer Satisfaction Index, Mann-Whitney, Online Application, Fishbein Multi-attribute

Judul: Comparison Analysis of Customer Satisfaction on User Experience of GrabFood and GoFood Application during the COVID-19 Pandemic
Abstrak: Pemerintah membuat kebijakan yang menyebabkan kapasitas restoran tidak diperbolehkan penuh dan juga membuat masyarakat melakukan kegiatan pemesanan dan pengantaran makanan dari rumah guna menangani kasus COVID-19. Penggunaan food delivery menjadi aktivitas kedua terbesar yang dilakukan masyarakat selama pandemi COVID-19. Walaupun GrabFood dan GoFood merupakan food delivery dengan pengguna terbanyak dan paling lama berkembang di Indonesia, namun mereka masih memiliki keluhan-keluhan terkait aplikasi mereka. Tujuan dari penelitian ini adalah untuk menganalisis karakteristik konsumen, mengidentifikasi kepentingan konsumen terhadap user experience aplikasi food delivery, dan menganalisis perbandingan tingkat kepuasan konsumen terhadap user experience aplikasi GrabFood dan GoFood. Penelitian menggunakan metode analisis deskriptif, Importance Performance Analysis (IPA), Customer Satisfaction Index (CSI), dan semantic differential. Hasil penelitian menyatakan terdapat 14 indikator dan tiga dimensi yang dinilai penting oleh konsumen, yaitu perspicuity, efficiency, dan dependability. Nilai tingkat kepuasan pengguna GrabFood 81,02%, sedangkan aplikasi GoFood sebesar 83,90%., The government made policies that prevented restaurant capacity from being full and also made the community carries out food ordering and delivery activities from home in dealing with COVID-19 cases. The use of food delivery services being the second largest activity carried out by the community during the COVID-19 pandemic. Although GrabFood and GoFood applications are food delivery services that have the most users and the longest growing in Indonesia, they still have complaints about their applications. The purpose of this study is to analyze consumer characteristics, identify consumer importance in the user experience of food delivery services, and analyze the comparison of consumer satisfaction levels with the user experience of the GrabFood and GoFood applications. This research uses descriptive analysis method, Importance Performance Analysis (IPA), Customer Satisfaction Index (CSI) and semantic differential. The results of the study state that there are 14 indicators and three dimensions that are considered important by consumers, namely perspicuity, efficiency, and dependability. The value of the satisfaction level of GrabFood users is 81.02%, while the GoFood application is 83.90%.
Keyword: Customer Satisfaction Index (CSI), food delivery, Importance Performance Analysis (IPA), kepuasan konsumen, user experience

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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