Judul: Model kalibrasi spektroskopi dengan pra-pemrosesan genetic algorithm (GA) (studi kasus: tanaman obat temulawak)
Abstrak: Pada era globalisasi ini, telah banyak perusahaan farmasi dan jamu yang berkembang pesat dan juga memanfaatkan tanaman obat dalam produk-produknya. Seiring dengan penggunaan tanaman obat yang digunakan juga harus mendapa perhatian khusus, terutama bagi kalangan industri farmasi dan jamu, untuk menjamin agar produknya tetap dapat bersaing dan diterima di kalangan masyarakat. Salah satu indikator kualitas tanaman obat adalah konsentrasi senyawa aktif yang terkandung pada tanaman obat harus dilakukan secara cepat dan akurat. Salah satu metodenya adalah dengan membuat model kalibrasi.
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Judul: Jaringan Syaraf Tiruan dan Algoritma Genetika dalam Pemodelan Kalibrasi (Studi Kasus: Tanaman Obat Temulawak)
Abstrak: The problems in prediction of calibration model are multicolinearity and the number of variables is larger than the number of observations. Principal Component Analysis-Artificial Neural Network-Genetic Algorithm (PCA-ANNGA) models were applied for the relationship between sample of concentration which is limited and transmittance data which is in large dimensions. A large number of variables were compressed into principal components (PC’s). From these PC’s, the ANN was employed for prediction of concentration. The principal components computed by PCA were applied as inputs to a backpropagation neural network with one hidden layer. The models was evaluated using GA for the best network structure on hidden layer. Root Mean Square Error (RMSE) for 80% training set and 20% testing set are 0.0314 and 0.5225, respectively. Distribution of data according to the percentage of training data and testing data were also very influential to obtain the best network structure with the smallest RMSE achievement. The best model for these methods is two layers Neural Network with eight neuron in the hidden layer.
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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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