Judul: Usability Testing on the Use of Exoskeletons in Palm Oil Harvesting-loading
Abstrak: Secara umum proses panen dan muat sawit yang dilakukan oleh petani menggunakan alat dan sistem secara manual. Pada pekerjaan pemanenan kelapa sawit secara manual sangat berisiko dan dapat menyebabkan musculoskeletal disorders (MSDs). Salah satu alternatif yang dapat dilakukan untuk mengurangi risiko MSDs tersebut yaitu dengan menggunakan teknologi eksoskeleton. Penelitian ini bertujuan mengidentifikasi pengaruh sebelum dan sesudah penggunaan eksoskeleton panen-muat sawit, menguji tingkat usabilitas, dan memberikan rekomendasi perbaikan pada eksoskeleton panen-muat sawit. Eksoskeleton yang saat ini sedang dikembangkan oleh kelompok riset Biomekatronika BRIN. Penelitian ini dilakukan di PT Perkebunan Nusantara VIII Cikasungka pada Februari – Mei 2023. Penelitian dimulai dengan studi pendahuluan dengan dilakukan pengujian Gangguan Otot-Rangka Akibat Kerja (GOTRAK) menggunakan kuesioner nordic body map. Kemudian dilakukan pengujian eksoskeleton menggunakan metode usability testing, kuesioner yang digunakan yaitu Kuesioner Usefulness, Satisfaction, and Ease of use (USE) dan System Usability Scale (SUS). Hasil dari kuesioner nordic body map menunjukkan bahwa keluhan GOTRAK terbanyak terdapat pada bagian punggung bawah dengan persentase 80%. Hasil pengukuran menggunakan kuesioner USE adalah 83% yang termasuk kategori “sangat layak”. Hasil pengukuran menggunakan kuesioner SUS yaitu 73,3 yang menunjukkan bahwa eksoskeleton ini termasuk dalam kategori acceptable. Selanjutnya pada penilaian skala adjective, eksoskeleton termasuk dalam penilaian excellent. Dan pada skor nilai eksoskeleton termasuk pada peringkat C. Penelitian ini khususnya diharapkan dapat meningkatkan kesehatan kerja pada pekerjaan panen-muat sawit, dikarenakan terbukti pekerjaan tersebut dapat menyebabkan musculoskeletal disorders., In general, the process of harvesting and loading palm oil carried out by farmers uses tools and systems manually. Manual harvesting of oil palm is very risky and can lead to musculoskeletal disorders (MSDs). One alternative that can be done to reduce the risk of MSDs is to use exoskeleton technology. This study aims to identify the effects before and after the use of palm oil harvest-loading exoskeletons, test the level of reusability, and provide recommendations for improvements to palm oil harvest-loading exoskeletons. The exoskeleton is currently being developed by the BRIN Biomechatronics research group. This research was conducted at PT Perkebunan Nusantara VIII Cikasungka in February – May 2023. The study began with a preliminary study by testing Work-Induced Skeletal Muscle Disorders (GOTRAK) using a nordic body map questionnaire. Then exoskeleton testing was carried out using the usability testing method, the questionnaires used were the Usefulness, Satisfaction, and Ease of use (USE) Questionnaire and System Usability Scale (SUS). The results of the nordic body map questionnaire showed that the most GOTRAK complaints were found in the lower back with a percentage of 80%. The measurement results using the USE questionnaire were 83% which belonged to the "very feasible" category. The measurement results using the SUS questionnaire are 73.3 which shows that this exoskeleton is included in the acceptable category. Furthermore, in the adjective scale assessment, exoskeletons are included in the excellent assessment. And the exoskeleton value score is included in the C rank. This research is especially expected to improve occupational health in oil palm harvesting, because it is proven that the work can cause musculoskeletal disorders.
Keyword: Nordic Body Map, System Usability Scale, USE Questionnaire

Judul: Precision Motion Analysis Using Motion Capture (Noitom) in Oil Palm Harvesting
Abstrak: Kegiatan pemanenan kelapa sawit di Indonesia masih dilakukan secara manual dengan menggunakan tenaga manusia. Aktivitas yang dilakukan secara manual ini sangat berisiko dalam menyebabkan gangguan otot rangka atau Musculoskeletal Disorders (MSDs). Penelitian ini bertujuan untuk memetakan tingkat risiko kerja berdasarkan postur pemanen dengan menggunakan analisis Range of Motion (ROM) dan Rapid Entire Body Assessment (REBA) untuk menjadi rekomendasi perbaikan postur kerja yang aman bagi pemanen kelapa sawit. Penelitian ini juga bertujuan untuk mengetahui korelasi antara ekstensi pada leher dengan tinggi badan, fleksi pada bahu dengan fleksi pada lengan bawah, dan fleksi pada pangkal paha dengan fleksi pada lutut pada pemanenan kelapa sawit, serta mengetahui gerakan yang besarnya dipengaruhi oleh letak bagian tubuh pada pemanenan kelapa sawit. Data pada penelitian ini diambil menggunakan metode motion capture lalu kemudian diolah dengan menggunakan software Axis Neuron dan Biomechanics of Bodies. Hasil analisis ROM menunjukkan tubuh bagian atas memiliki risiko lebih tinggi mengalami MSDs dengan leher, bahu, dan lengan bawah menjadi bagian tubuh yang paling banyak berada dalam zona bahaya. Kegiatan pemanenan kelapa sawit mendapat skor 12-14 pada penilaian REBA yang berarti perlu segera dilakukan intervensi ergonomika untuk memperbaiki metode ataupun prosedur kerja agar risiko dapat dimitigasi ataupun diminimalisir., Oil palm harvesting activities in Indonesia are still carried out manually using human labor. This manual activity is very risky to cause Musculoskeletal Disorders (MSDs). This study aims to map the level of work risk based on the posture of harvesters using Range of Motion (ROM) analysis and Rapid Entire Body Assessment (REBA) to be a recommendation for improving safe work postures for oil palm harvesters. This study also aims to determine the correlation between neck extension with height, shoulder flexion with elbow flexion, and hip flexion with knee flexion in oil palm harvesting, and determine the movements that are most influenced by the location of body parts in oil palm harvesting. The data were taken using the motion capture method and then processed using Axis Neuron and Biomechanics of Bodies. The ROM analysis results show that the upper body has a higher risk of MSDs with the neck, shoulders, and forearms as the body parts that are most in the danger zone. Oil palm harvesting activities received a score of 12-14 on the REBA assessment which means ergonomic interventions need to be carried out immediately to improve work methods or procedures so that risks can be mitigated or minimized.
Keyword: oil palm harvesting, ergonomy, motion analysis, ROM, REBA

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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