Judul: Klasifikasi Fragmen Metagenom Menggunakan Metode Probabilistic Neural Network (PNN)
Abstrak: Teknologi pada bidang bioinformatika terus berkembang, khususnya untuk analisis metagenom. Metagenom merupakan komunitas mikrob genom yang sampelnya diambil langsung dari lingkungan. Fragmen metagenom yang dihasilkan dari pengambilan sampel masih bercampur antar-organisme. Tujuan penelitian ini adalah melakukan klasifikasi fragmen metagenom ke dalam takson genus. Penelitian ini menggunakan metode Probabilistic Neural Network (PNN) dengan ekstraksi fitur Gray Level Co-occurence Matrix (GLCM). Penelitian dilakukan pada panjang fragmen 200 bp, 400 bp, 800 bp, dan 1 Kbp. Data yang digunakan sebanyak 100 organisme dalam variasi 10 genus dengan 5-fold cross validation. Untuk mendapatkan nilai fitur fragmen dibutuhkan formulasi 8 fitur persamaan haralick. Setelah hasil fitur didapat, kemudian diklasifikasi dengan metode PNN. Dari klasifikasi PNN, diperoleh akurasi pada rentang 92.8%-93.6% berdasarkan panjang fragmen. Nilai spesifisitas pada keempat panjang fragmen mencapai 96%. Berbeda dengan spesifisitas, nilai sensitivitas yang diperoleh sekitar 64%-68%. Selisih akurasi, sensitivitas, dan spesifisitas pada panjang 200 bp dan 1 Kbp tidak jauh berbeda. Dari hasil tersebut, terdapat kecenderungan bahwa semakin panjang fragmen yang digunakan maka akurasi semakin meningkat.
Keyword: GLCM, metagenome, PNN

Judul: Klasifikasi Fragmen Metagenome Menggunakan KNN dan PNN dengan Ekstraksi Fitur Gray Level Co-occurrence Matrix (GLCM) pada Variasi Panjang Fragmen
Abstrak: Bioinformatics is a field of study which is developing rapidly in Indonesia. The main focus of this study is to classify metagenome fragment into some taxonomies using GLCM that has 13 features. The training data used in the classification process are 50 organisms with 5-fold cross validation. The DNA combination sequences inside a fragment can be seen as a 1xN image, where N is the fragment’s length in two-dimension’s matrix. The result from those features will be classified using PNN and KNN. The research shows that the accuracy percentage with all lengths variety, including 200 bp, 1 Kbp, 3 Kbp, and 10 Kbp, are 100%. It can be stated that the variety fragment’s length does not affect the accuracy. In addition, it can be concluded that GLCM feature extraction method can be prospectively implemented for classifying metagenome fragment.
Keyword: Bogor Agricultural University (IPB), PNN, KNN, GLCM, Fragment

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.
Keyword: