Judul: Design of Chili Mobile Application Prototype Based on Supply  Chain Management using Lean UX Method
Abstrak: Cabai merupakan komoditas sayuran unggulan nasional dan daerah karena memberikan keuntungan bagi para petani, baik secara biofisik, sosial maupun ekonomi. Faktor penyebab dari tingginya harga cabai adalah banyaknya permintaan cabai merah pada hari raya, dan faktor penyebab lainnya juga disebabkan dari faktor cuaca yang tidak menentu. Tujuan penelitian ini adalah menghasilkan prototipe versi mobile app dari aplikasi SCM Cabai. Penelitian ini dikembangkan dengan metode Lean UX yang terdiri dari empat tahapan. Tahap Create an Minimum Viable Product merupakan implementasi aplikasi yang menghasilkan prototipe. Pada tahap ini prototipe medium-fidelity dibuat dengan menggunakan aplikasi Figma. Tahap Run An Experiment adalah tahap pengujian prototipe aplikasi berbasis mobile dengan cara demo dan riview oleh satu orang UX desainer dan dua orang pengembang aplikasi versi web. Setelah dilakukan pengujian didapatkan nilai success rate dari tahap run an experiment yaitu sebesar 86.66 %. Terakhir, pada Feedback and Research pengujian dengan metode thinking aloud dilakukan oleh lima pengguna pelaku rantai pasok. Berdasarkan data yang didapatkan, nilai success rate pengujian pada iterasi pertama ini adalah sebesar 86 %. Hasil dari penelitian dapat disimpulkan bahwa aplikasi SCM Cabai berbasis mobile ini sangat membantu para petani dan juga pelaku rantai pasok lainnya dalam melakukan proses distribusi dan pencatatan lahan cabai., Chili is a national and regional superior vegetable commodity because it provides benefits for farmers, both biophysically, socially and economically. The factor causing the high price of chili is the large number of requests for red chili on holidays, and other contributing factors are also caused by erratic weather factors. The purpose of this study is to produce a prototype mobile app version of the Chili SCM application. This research was developed using the Lean UX method which consists of four stages. The Create an Minimum Viable Product stage is an application implementation that produces a prototype. At this stage a medium-fidelity prototype was created using the Figma application. The Run An Experiment stage is the testing phase of a mobile-based application prototype by means of a demo and review by one UX designer and two web version application developers. After testing, the success rate value from the run an experiment stage was 86.66 %. Finally, in Feedback and Research, testing using the thinking aloud method was carried out by five supply chain actors. Based on the data obtained, the success rate of the test in this first iteration is 86%. The results of the study can be concluded that this mobile-based Chili SCM application is very helpful for farmers and also other supply chain actors in carrying out the distribution and recording process of chili land
Keyword: chili, lean ux, supply chain management, user experience

Judul: Perancangan User Experience Aplikasi Mobile Tokocabai dengan Metode Lean UX
Abstrak: Cabai merupakan komoditas pertanian di Indonesia yang memiliki produksi dan permintaan yang cukup tinggi, namun harga cabai di pasar seringkali mengalami fluktuasi harga yang menyebabkan kerugian di kalangan petani cabai. Teknologi informasi berupa marketplace dinilai dapat membantu petani dalam meningkatkan keuntungan penjualan komoditas pertanian khususnya cabai. Sebelumnya, marketplace Tokocabai sudah tersedia untuk versi web, namun untuk versi mobile belum tersedia. Penelitian ini bertujuan menghasilkan rancangan prototipe mobile user experience sistem Tokocabai yang sesuai dengan kebutuhan para praktisi dan pengguna. Metode Lean UX memiliki empat tahap cycle yaitu declare assumption, create an MVP, run an experiment, dan feedback and research. Penelitian ini dilakukan sebanyak dua iterasi, pada iterasi pertama pengujian dilakukan dengan usability testing terhadap lima orang responden, sedangkan pada iterasi kedua evaluasi dilakukan dengan heuristic evaluation on mobile interface. Pada iterasi pertama, hasil usability testing menunjukkan bahwa seluruh responden dapat menyelesaikan task yang diberikan, selain itu pada iterasi kedua, telah disajikan daftar evaluasi yang dapat dijadikan acuan perbaikan pada penelitian berikutnya. Hasil akhir penelitian ini berupa prototipe aplikasi mobile Tokocabai yang sudah disesuaikan bagi kebutuhan praktisi dan pengguna., Chili is an agricultural commodity in Indonesia which has a quite high production and demand, but chili prices in the market often experiences price fluctuations which cause losses among chili farmers. Marketplace is considered to be able to help farmers increase profits from selling agricultural commodities, especially chilies. Previously, the Tokocabai marketplace was available for the web version, but the mobile version is not yet available. This study aims to produce a mobile user experience prototype design for the Tokocabai system that suits the needs of practitioners and users. The Lean UX method has four cycle stages, namely declare assumption, create an MVP, run an experiment, and feedback and research. This research was conducted in two iterations, in the first iteration the test was carried out by usability testing on five respondents, while in the second iteration the evaluation was carried out by heuristic evaluation on mobile interface. In the first iteration, the results of usability testing showed that all respondents were able to complete the given task. In the second iteration, an evaluation list was presented which could be used as a reference for improvement in subsequent research. The final result of this research is a prototype of the Tokocabai mobile application that has been adapted to the needs of practitioners and users.
Keyword: cabai, lean ux, marketplace, 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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