Judul: Pola Sebaran Ikan Pelagis di Sekitar Rumpon Portable di Perairan Ambon
Abstrak: Pengoperasian rumpon portable belum pernah dilakukan pada perairan laut dalam sehingga informasi terkait sebaran dan tingkah laku ikan masih minim diketahui. Informasi penyebaran ikan berdasarkan parameter lingkungan dan kedalaman perairan sangat penting untuk menunjuang keberhasilan operasi penangkapan. Tujuan penelitian ini adalah untuk menghitung gaya apung dan gaya tenggelam pada rumpon portable, mengidentifikasi pola sebaran schooling ikan, dan mengidentifikasi sebaran suhu permukaan laut di sekitar rumpon portable. Metode penelitian menggunakan Observasi lapang sebanyak dua trip operasi penangkapan dimulai dari bulan Oktober-November 2021. Data yang digunakan pada penelitian ini adalah data akustik berupa sebaran schooling serta data sekunder berupa suhu yang diperoleh dari website oseanografi https://marine.copernicus.eu/. Hasil penelitian menunjukan bahwa Rumpon portable memiliki gaya apung sebesar 98164,91 gs, dan gaya tengeglam 90763,91 gs. Ekstra bouyancy rumpon portable sebesar 75%. Sebaran schooling ikan pelagis di sekitar rumpon portable cenderung membentuk kelompok dengan jumlah yang besar pada waktu pagi dan siang dibandingkan dengan malam hari. Sebaran schooling berdasarkan kedalaman cenderung berada di permukaan pada waktu pagi dan siang di kedalaman 5-39 m, sedangkan pada malam hari berada pada kedalaman yang lebih rendah antara 40-60 m. Keberadaan schooling ikan di sekitar rumpon portable berada pada suhu antara 25-30 ., The operation of portable FADs has never been carried out in deep sea waters, so information regarding the distribution and behavior of fish is still minimal. Information on fish distribution based on environmental parameters and water depth is very important to support the success of fishing operations. The study aimed to calculate the buoyancy and sinking forces on portable FADs, identify distribution patterns of schooling fish, and identify the distribution of sea surface temperature around portable FADs. The research used field observationon as many as two fishing operation trips starting from October-November 2021. The data used in this study were acoustic in the form of schooling distribution and secondary data in the form of temperature obtained from the oceanographic website https://marine.copernicus.eu/. The results showed that the FAD portable has a buoyancy force of 98164,91 gs, and a sinking force of 90763,91 gs. Extra bouyancy of portable FADs is 75%. The distribution of pelagic schooling fish around portable FADs tends to form groups with large numbers in the morning and afternoon compared to at night. The distribution of schooling based on depth tends to be on the surface in the morning and afternoon at a depth of 5-39 m, while at night, it is at a lower depth of between 40-60 m. The presence of schooling fish around portable FADs is at a temperature between 25-30 .
Keyword: Banda Sea, purse seine, portable FAD, schooling, temperature

Judul: Pola Sebaran Ikan di Sekitar Rumpon Portable, Kaitannya dengan Produktivitas Tangkapan Payang di Kabupaten Tegal
Abstrak: Keterbatasan informasi sebaran schooling ikan target tangkapan, baik secara spasial maupun secara temporal menyebabkan produktivitas hasil tangkapan nelayan payang di PPP Larangan berkurang. Untuk mengatasi masalah tersebut, diperlukan penerapan rumpon portable sebagai alat bantu penangkapan untuk meningkatkan produktivitas tangkapan. Tujuan penelitian ini adalah mendapatkan informasi sebaran ikan di sekitar rumpon portable berdasarkan waktu, kedalaman, komposisi hasil tangkapan, serta produktivitas dan efektivitas payang. Metode penelitian yang digunakan adalah experimental fishing. Data yang digunakan meliputi distribusi schooling ikan berdasarkan waktu dan kedalaman, jenis spesies hasil tangkapan, dan bobot tangkapan. Hasil penelitian menunjukkan schooling ikan paling banyak terdeteksi pukul 05.00-07.00 WIB pada kedalaman 0-4 meter, sedangkan paling sedikit pukul 10.00-11.00 WIB pada kedalaman 8,1-12 meter. Komposisi hasil tangkapan terdiri dari teri nasi 347 kg dan teri putih 251 kg. Produktivitas rata-rata payang dengan rumpon portable adalah 37,38 kg/trip, sedangkan tanpa rumpon hanya 34,06 kg/trip. Penggunaan rumpon portable dalam payang memiliki efektivitas 52,3%, lebih tinggi daripada payang tanpa rumpon yang hanya memiliki efektivitas 47,7%., Limited information on the spatial and temporal distribution of target fish schooling reduces catch productivity for payang fishermen in PPP Larangan. To address this, portable fish aggregating devices (FADs) are used to increase catch productivity. The study aims to gather fish distribution information around the portable FADs based on time, depth, catch composition, and payang's productivity and effectiveness. Experimental fishing is the research method, collecting data on fish schooling distribution by time and depth, species composition, and catch weight. Results show that fish schooling is most detected between 05.00-07.00 AM at depths of 0-4 meters, and least detected between 10.00-11.00 AM at depths of 8.1-12 meters. The catch composition includes 347 kg of Stolephorus commerson and 251 kg of Stolephorus indicus. Payang's average productivity with portable FADs is 37.38 kg/trip, compared to 34.06 kg/trip without FADs. The use of portable fish aggregating devices (FADs) in payang has an effectiveness of 52.3%, higher than payang without FADs at 47.7%.
Keyword: effectiveness, fish distribution, payang, productivity, portable fish  aggregator

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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