Judul: Penggunaan Metode Transformasi Diferensial untuk Menyelesaikan Persamaan Hirota-Satsuma-KdV
Abstrak: Fenomena gelombang permukaan dapat diformulasikan ke dalam model matematika berbentuk persamaan diferensial. Salah satu model matematika yang menjelaskan gelombang permukaan adalah model Hirota-Satsuma Coupled Korteweg-de Vries (KdV) dan Coupled modified Korteweg-de Vries (mKdV). Sistem persamaan Hirota-Satsuma Coupled KdV dan Coupled mKdV merupakan pengembangan dari persamaan KdV dan persamaan Hirota-Satsuma. Salah satu metode pendekatan untuk mencari penyelesaian kedua model persamaan diferensial tersebut adalah metode transformasi diferensial. Metode ini menggunakan konsep dasar deret Taylor untuk memperoleh solusi persamaan diferensial dalam bentuk polinomial. Hasil penelitian menunjukkan bahwa galat antara pendekatan solusi dengan metode transformasi diferensial dan solusi eksak dari model Hirota-Satsuma Coupled KdV dan Coupled mKdV sangat kecil. Selain itu, diperoleh bahwa amplitudo gelombang mengalami penurunan pada saat perambatan.
Keyword: gelombang permukaan, Hirota-Satsuma Coupled KdV dan Coupled mKdV, metode transformasi diferensial

Judul: Penggunaan Metode Homotopi untuk Menyelesaikan Persamaan KdV (Korteweg-de Vries)
Abstrak: Natural phenomena can be explained using nonlinear mathematical models. In this paper, we studied the solution of KdV equation using the Homotopy method. The KdV equation is used for describing both surface and internal waves. One of the solutions is called a solitary wave. The use of homotopy method to solve the KdV equation required a nonlinear operator which was determined by the nonlinear form of the KdV equation itself. Based on this operator, a recursive formula was obtained to get a sequence of the KdV solution. The higher the sequence order of the sequence used, the closer to the exact solution of the KdV equation.
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Judul: Aktivitas Makan dan Status Gizi Lutung Perak (Trachypithecus cristatus) di Pusat Primata Schmutzer, Taman Margasatwa Ragunan, Jakarta
Abstrak: Silvered leaf monkeys (Trachypithecus cristatus) are primate that live in groups on trees and consume leaves. The feeding activities of silvered leaf monkey relates to the fulfillment of their dialy energy. The energy is needed for the continuity of the group existence. The feeding activities of silvered leaf monkeys have several activities. They are observing, taking, sorting, processing, biting, chewing, ingesting, pulling out their mouth, and disposing the feed. The study aimed to identify the feeding activities, kind and composition of feed, nutrient consumption and energy of silvered leaf monkeys (Trachypithecus cristatus) in Schmutzer Primate Center (PPS), Ragunan Zoo, Jakarta. Data is collected from June to September 2011 with total of 480 hours observations. The data collection for the feeding activities was performed using ad libitum and focal animal sampling methods. Based on the observations, there were three types of activities with the highest frequency. Such as resting, locomotion, and feeding activity at 44.87%, 40.89%, and 38.70%. Respectively the chewing feed activities on infants were the higest of the feeding activities (36.90%). Silvered leaf monkeys in Schmutzer Primate Center (PPS) have good palatability in type of lamtoro leaves (Leucaena glauca). The result of the study revealed that adult and infants monkeys have sufficient dry matter and protein consumption (40,5 g/BW/d, 8 g/BW/d and 63 g/BW/d, 12,5 g/BW/d), but less for fat and energy (2,37 g/BW/d, 23,87 kcal/BW/d and 3,75 g/BW/d, 37 kcal/BW/d), while nutrient recommendation
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