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 K-Means
Abstrak: The practice of plagiarism in programming assignments can be easily done by students. Thus, a system that can detect this practice, i.e., by grouping similar programs into a cluster, is needed. K-Means clustering is a method of flat clustering that has been used to determine similar codes based on the structure of the source codes. The objective of this research is to make the checking process automatic. This research uses a sample of 92 source codes in C comprising 9 groups based on the source code structure similarity. In this study we conducted two experiments, i.e., by determining the number of clusters (manual) and without determining the number of clusters (automatic). The results indicate that the manual experiment resulted in a higher Rand Index (91.35%) and a faster execution time. The system is able to perform automatic clustering process with a Rand Index of 90.63%. The automated clustering does not have significant difference of Rand index, implying the performance is good enough for the clustering without determining the K value first
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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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