Judul: Deteksi Penjiplakan Kode Program C dengan Metode Bisecting KMeans pada Kode yang Memiliki Makro
Abstrak: Submission of programming tasks in digital form is vulnerable to plagiarism because the number of submitted codes can reach hundreds every week, making the process of plagiarism checking manually infeasible. Therefore we need a system that can detect plagiarism program code automatically. This has been done in previous studies using the K-means and bisecting K-means, but previous research assumes no preprocessor directive in the program code. Meanwhile, the use of preprocessor directive can change the structure of the program code that could affect the ability of the system to detect plagiarism. The purpose of this study is to detect codes that uses macro and compare the results obtained with previous research. The results obtained showed an increased accuracy in detecting the whole program code from 85 % to 89 %. Testing for each type of program code result in an increase of accuracy from 20%-40% to 80%.
Keyword: Bogor Agricultural University (IPB), structure-oriented similarity, preprocessor directive, plagiarism detection

Judul: Pendeteksian Penjiplakan Kode Program C dengan Bisecting K-means
Abstrak: Plagiarism of source codes assignments is a widespread problem in academic institutions. Manual plagiarism detection is time and energy consuming. Therefore, a system that can help detecting this plagiarism is needed. The detection can be done by grouping similar source codes based on their structure. This method is used in previous research by using automatic K-means iterations algorithm. That algorithm, although produced decent clusters, had a long execution time. The purpose of this research is to improve the time efficiency and clusters result quality by using bisecting K-means algorithm. The results showed a significant improvement in execution time from 11.68 seconds to 6.64 seconds. Bisecting K-means also produced fewer clusters with slightly better Rand Index than K-means iterations. Furthermore, experiments using 2-gram to 6-gram showed that 4-gram resulted in the best performance
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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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