Judul: Modifikasi Pembentukan Spectrum pada Metode Spectral Alignment untuk Pengoreksian DNA Sequencing Error
Abstrak: Graph based DNA sequence assembly is actually used to generate contigs form reads produced by second generation sequencer. However, graph based DNA sequence assembly is very sensitive against sequencing error. The existence of sequencing errors will increase the complexity of graph. Meanwhile, every process of sequencing always produce sequencing errors. This research aims to improve the performance of DNA sequencing error correction based on the spectral alignment by implementing a statistical approach. This approach generate the spectrum of solid tuple by choosing tuples that belong to the highest 75% of the tuple occurencies distribution. Reads containing sequencing errors are corrected using tuple references that belong to the solid tuple spectrum. Evaluation is conducted using Velvet, a DNA assembly software. The results show that our approach can reduce the complexity of graph produced by the previous approach up to 45%.
Keyword: Bogor Agricultural University (IPB), statistical approach, DNA sequence assembly, spectral alignment, DNA sequencing error

Judul: Koreksi DNA Sequencing Error dengan Metode Spectral Alignment
Abstrak: Second generation DNA sequencing technology is able to generate reads in a massive amount and in a relatively short time compared to the traditional Sanger Shotgun technology. Graph based DNA sequence assembly is used to handle these big data in assembly step. However, the graph based DNA sequence assembly is sensitive to sequencing error. This problem can be solved by performing an error correction step before or after the assembly process. In this research, a software to detect and correct sequencing error in DNA sequence data was developed by employing spectral alignment technique. This technique is implemented as a pre-processing step before the DNA sequence assembly process. DNA sequences which contain error are generated using MetaSim software. Errors in the data sequences are corrected using the software developed in this research. The results are evaluated using the Velvet assembler by comparing the complexity of the graph produced, represented by the number of nodes in the graph. The evaluation results show that the data sequences with error produce more complex graph than the corrected data sequences. It can be concluded that the correction of DNA sequencing error using spectral alignment method can simplify the complexity of graph produced by the DNA sequence assembly step
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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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