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: Penyelesaian masalah gelombang dispersi taklinear dengan menggunakan metode homotopi
Abstrak: Many natural phenomena can be presented in mathematical models, such as the nonlinear Whitham-Broer-Koup (WBK) wave equation. WBK equation describes wave propagation in shallow waters containing dispersion factor. In this paper, WBK equation will be solved by using homotopy method. Homotopy method is an approximated analytical method, which can be used to obtain the solution of nonlinear problems. The results of this study indicate that homotopy method is highly efficient to solve the WBK equation. Errors resulting from this method are very small, so the solution obtained is very close to its exact solution. One special case of WBK equation discussed in this study is Boussinesq equation, which has a wave number of 0.2 and a frequency of 0.04. The wave initially form a single wave, but then it breaks into two waves, each moving in opposite directions at equal speed.
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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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