Judul: Pengaruh Kualitas Pelayanan Gojek dalam Menerapkan Protokol Kesehatan J3K terhadap Kepuasan dan Loyalitas Pelanggan
Abstrak: Indonesia menjadi salah satu negara yang terdampak pandemi Covid-19. Tingginya kasus terkonfirmasi di Indonesia menyebabkan Indonesia harus melaksanakan Pembatasan Sosial Berskala Besar (PSBB). Sehingga segala kegiatan hanya bisa dilakukan dari rumah saja. Gojek sebuah perusahaan transportasi on-demand melakukan inovasi dengan membuat kampanye protokol kesehatan J3K. J3K berarti jaga kesehatan, jaga kebersihan, dan jaga keamanan. J3K merupakan upaya Gojek dalam meningkatkan kualitas pelayanan Gojek. Penelitian ini bertujuan untuk menganalisis pengaruh kualitas pelayanan Gojek dalam menerapkan protokol kesehatan J3K terhadap kepuasan dan loyalitas pelanggan. Penelitian dilakukan dari bulan Juni sampai Agustus 2021 kepada pengguna layanan Gojek di DKI Jakarta. Teknik penentuan sampel menggunakan voluntary sampling. Teknik analisis data yang digunakan adalah analisis deskriptif dan structural equational modelling-partial least square (SEM PLS). Hasil penelitian menunjukkan bahwa kualitas pelayanan berpengaruh pada kepuasan pelanggan dan loyalitas pelanggan pada layanan Gojek dalam menerapkan protokol kesehatan J3K, serta kepuasan pelanggan berpengaruh pada loyalitas pelanggan. Hal ini berarti kualitas pelayanan Gojek dalam menerapkan protokol kesehatan J3K mampu melebihi ekspektasi pelanggan dan mampu membangun loyalitas bagi pelanggan., Indonesia is one of the countries affected by the Covid-19 pandemic. The high number of confirmed cases in Indonesia has forced Indonesia to implement Large-Scale Social Restrictions (PSBB). So that all activities can only be done from home. Gojek, an on-demand transportation company, innovates by creating a J3K health protocol campaign. J3K means taking care of your health, keeping it clean, and keeping it safe. J3K is Gojek's effort to improve the quality of Gojek's services. This study aims to analyze the effect of Gojek's service quality in J3K health protocol implementation toward customer satisfaction and loyalty. The research was conducted from June to August 2021 with Gojek’s customers in DKI Jakarta. The voluntary sampling was used as sampling methode. The data analysis technique used descriptive analysis and structural equational modeling-partial least square (SEM PLS). The results showed that service quality affected customer satisfaction and loyalty to Gojek services in implementing the J3K health protocol, then customer satisfaction affected on customer loyalty. This means Gojek’s service quality in implementing J3K health protokol that be able to increase customer expectation and also be able to create the customer loyalty.
Keyword: Customer satisfaction, Customer loyalty, Gojek, Health protocol, Service quality

Judul: The Effect of Logistics Service Quality on  Customer Satisfaction and Customer Loyalty on JNE and J&T Express Users in  Jabodetabek
Abstrak: Peningkatan jumlah pengguna e-commerce menyebabkan tren belanja online menjadi populer di kalangan masyarakat Indonesia selama masa pandemi COVID-19. Jasa penyedia logistik memiliki peran penting dalam perkembangan suatu e-commerce. JNE dan J&T Express merupakan perusahaan industri logistik di Indonesia. Perusahaan jasa logistik harus memperhatikan kualitas layanan karena merupakan salah satu kunci dalam meraih keunggulan kompetitif yang berdampak pada kepuasan dan tingkat loyalitas pelanggan. Penelitian ini bertujuan untuk menganalisis pengaruh logistics service quality terhadap customer satisfaction dan customer loyalty pada pengguna JNE dan J&T Express di Jabodetabek. Data dalam penelitian ini diperoleh melalui data primer dan data sekunder. Analisis data yang digunakan adalah analisis Independent Sample T-Test dan analisis SEM-AMOS dengan sampel sebanyak 407 responden. Teknik pengambilan sampel yaitu metode non probability sampling jenis convenience sampling. Hasil penelitian ini menunjukkan bahwa logistics service quality berpengaruh positif dan signifikan terhadap customer satisfaction dan customer loyalty, The increasing number of the e-commerce shopping trend online become popular among the Indonesian people during the COVID-19 pandemic. Logistics service providers have an important role in the development of an e-commerce. JNE and J&T Express are logistics industry companies in Indonesia. Logistics service companies must pay attention to service quality because it is one of the keys to achieve competitive advantage that has an impact on customer satisfaction and customer loyalty. This study aims to analyze the effect of logistics service quality on customer satisfaction and customer loyalty on JNE and J&T Express users in Jabodetabek. The data in this study were obtained through primary and secondary data. The method that is used to analyze the data is Independent Sample T-Test analysis and SEM-AMOS analysis as a methodology with a sample of 407 respondents. The sampling technique is a non-probability sampling and convenience sampling. The results of this study indicate that logistics service quality has a positive and significant effect on customer satisfaction and customer loyalty
Keyword: customer satisfaction, logistics service, loyalty, SEM-AMOS, service  quality

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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