Judul: Identifikasi DNA Bakteri Menggunakan Metode Ekstraksi Ciri Spaced K-Mers dengan Jaringan Syaraf Tiruan sebagai Classifier
Abstrak: Feature extraction is the process of taking an object identifiers that describes it’s characteristics. In this study, spaced k-mers feature extraction method was employed. This method was used to retrieve the data identifier of DNA sequence of the three genus, namely Bacillus, Burkholderia, and Pseudomonas. Artificial neural network was used to analyze molecular biology data from the three genus. The feature extraction methods uses the following setup: w = 3, and d = 0, 1, 2 and fragment length 100 bp, 400 bp, 800 bp, and 1 Kbp. The best sensitivity and the best specificity were achieved for known organisms at 1 Kbp fragment length with value 0.9716 and 0.9854, respectively
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Judul: Identifikasi DNA Bakteri Menggunakan Metode Ekstraksi Ciri Rantai Markov dengan Probabilistic Neural Network Sebagai Classifier
Abstrak: Genetic differences among organisms motivate many research in DNA identification system. DNA identification system has two main parts: Feature Extraction Method and Classification Method. This study aims to identify the DNA with feature extraction using first order and second order Markov chain combined with Probabilistic Neural Network (PNN) classification method. DNA sequence is derived from the genus Bacillus, Clostridium, Lactobacillus, Mycobacterium, and Staphylococcus with sequence lengths of 100 bp, 200 bp, 400 bp, 800 bp, and 1000 bp. These data were obtained from the National Center for Biotechnology Information (NCBI). The results of this research show that the best sensitivity value is 0.7136 and the best specificity value is 0.9284. These results were obtained when the length of the sequence is 1000 bp and the feature extraction method used is second order Markov Chain. The greater the length of the sequence, the greater the sensitivity and specificity values.
Keyword: sequence DNA, Probabilistic Neural Network, markov chain, identification

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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