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: Analysis of Student Satisfaction towards Online Food Delivery Services during COVID-19 Pandemic
Abstrak: Pelaku bisnis di Indonesia mulai menjadikan internet sebagai alat penunjang kegiatan bisnis mereka karena dapat mempermudah hubungan bisnis dengan pelanggan secara lebih luas dan efisien. Selama kondisi pandemi COVID- 19, ada peningkatan aktivitas jual beli yang dilakukan secara daring dan menjalankan prinsip pengantaran, terutama untuk sektor restoran. Penelitian ini bertujuan untuk mengetahui tingkat kepuasan dalam dua perusahaan yang menyediakan layanan jasa antar makanan. Penelitian ini menggunakan data primer dari 108 responden mahasiswa IPB yang melakukan pembelian secara daring. Metode analisis yang digunakan adalah analisis deskriptif, importance performance analysis (IPA), dan customer satisfaction index (CSI). Hasil penelitian menunjukkan bahwa tingkat kepuasan pada jasa pesan antar makanan secara daring diantaranya disebabkan oleh pelayanan yang diberikan oleh driver. Berdasarkan hasil analisis metode IPA, perusahaan penyedia layanan jasa pesan antar makanan perlu meningkatkan kinerja pada atribut-atribut yang memiliki tingkat kepentingan tinggi namun tingkat kinerjanya rendah, diantaranya atribut harga yang lebih rendah, lokasi dan harga promo., Businesses in Indonesia are starting to use the internet as a tool to support their business activities because it can facilitate business relations with customers more broadly and efficiently. During the COVID-19 pandemic, there has been an increase in online buying and selling activities and implementing the principle of delivery, especially for the restaurant sector and the food business, where orders can be made boldly. This study aims to determine the level of satisfaction in the two companies that provide food delivery services. This study used primary data from 108 IPB student respondents who made bold purchases. The analysis method used were descriptive analysis, importance performance analysis (IPA), and customer satisfaction index (CSI). The results showed that the level of satisfaction in the two companies was due to the services provided by the driver. Based on the results of the analysis of the important performance analysis method (IPA), food delivery service companies that can improve performance on attributes that have a high level of importance but have low levels of performance, include lower price attributes, location and promo prices.
Keyword: consumer satisfaction, COVID-19, food products, online shopping

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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