Judul: User Research on E-Commerce Application Regarding The Use of Digital Nudge to Form Responsible Consumption
Abstrak: Teknologi informasi yang semakin kompleks telah memicu pertumbuhan e-commerce dengan pengaruh besar pada kehidupan manusia. E-commerce telah meningkat seiring dengan perkembangan internet yang meluas. Pandemi COVID-19 mempercepat pertumbuhan e-commerce di Indonesia sebagai respons terhadap kebutuhan untuk menghindari kontak fisik. Strategi nudging diperlukan untuk mendorong konsumsi bertanggung jawab yang sejalan dengan Sustainable Development Goals (SDGs) Nomor 12. Penelitian ini berfokus pada sikap dan perilaku serta efektifitas digital nudge pengguna usia 18-35 tahun melalui tahapan persiapan instrumen, rekrutmen partisipan, uji pengguna, wawancara, pengisian kuesioner, analisis hasil, dan dokumentasi desain. Hasil yang diperoleh terdapat ketidaksesuaian antara sikap dan perilaku. Partisipan memiliki pemahaman dan sikap yang baik terhadap fitur seperti donasi. Namun, perilaku belum mencerminkan hal tersebut dikarenakan alasan seperti ketidakjelasan informasi dan tujuan, biaya, dan ketidaktahuan. Selain itu, fitur rating serta kesulitan menerapkan kemasan yang ramah lingkungan juga menjadi perhatian., The increasingly complex information technology has led to the growth of e-commerce, significantly impacting human lives. E-commerce has grown alongside the widespread development of the Internet. The COVID-19 pandemic has sped up e-commerce growth in Indonesia as a response to the need to avoid physical contact. Nudging strategies are needed to encourage responsible consumption in line with Sustainable Development Goals (SDGs) Number 12. This research focuses on the attitudes and behaviors, as well as the effectiveness of digital nudges for users aged 18-35, through stages including instrument preparation, participant recruitment, user testing, interviews, questionnaire completion, result analysis, and design documentation. The results show a mismatch between attitudes and behaviors. Participants have good understanding and positive attitudes towards features like donations. But, their behaviors don't reflect this due to reasons like unclear information and objectives, costs, and lack of awareness. Additionally, features like rating and the difficulty in implementing eco-friendly packaging are also concerns.
Keyword: digital nudge, e-commerce, konsumsi bertanggung jawab, responsible consumption

Judul: Redesign of digital nudges in e-commerce applications to promote responsible consumption
Abstrak: Peningkatan konsumsi bertanggung jawab telah mempengaruhi berbagai aspek layanan teknologi, khususnya dalam e-commerce. Pertumbuhan pesat platform e-commerce, terutama Tokopedia, telah mendorong perkembangan ekonomi, namun juga membawa dampak negatif yang tak terhindarkan, terutama terkait keberlanjutan lingkungan dan sosial. Konsep konsumsi bertanggung jawab menekankan pada pengurangan penggunaan sumber daya alam, bahan berbahaya, dan limbah untuk menjamin masa depan yang berkelanjutan. Penelitian ini bertujuan untuk merancang digital nudge yang efektif di platform e-commerce Tokopedia untuk mendorong kebiasaan konsumsi bertanggung jawab serta menguji rancangan prototipe. Penelitian dilakukan dalam beberapa tahapan yakni pembangkitan ide menggunakan SCAMPER, prototyping, uji kebergunaan, dan wawancara. Prototipe redesain berhasil meningkatkan penggunaan fitur responsible consumption berupa fitur donasi dari 40% menjadi 67%., The increase in responsible consumption has impacted various aspects of technology services, particularly in e-commerce. The rapid growth of e-commerce platforms, especially Tokopedia, has driven economic development but also brought unavoidable negative effects, particularly related to environmental and social sustainability. The concept of responsible consumption emphasizes reducing the use of natural resources, hazardous materials, and waste to ensure a sustainable future. This research aims to design an effective digital nudge on the Tokopedia e-commerce platform to encourage responsible consumption habits and test the prototype design. The study was conducted in several stages, including generating ideas using SCAMPER, prototyping, usability testing, and interviews. The redesigned prototype successfully increased the use of responsible consumption features, such as donation features, from 40% to 67%.
Keyword: digital nudge, E-commerce, Konsumsi yang bertanggung jawab, SCAMPER

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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