Judul: Kendali mutu daun jati belanda (Guazuma ulmifolia) menggunakan fotometer jinjing dan teknik pengenalan pola
Abstrak: Jati belanda (Guazuma Ulmifolia) merupakan tanaman obat tradisional. Kendali mutu tanaman diperlukan untuk mengontrol kualitas dan keamanan obat. Pada penelitian ini keragaman mutu daun jati belanda dievaluasi menggunakan fotometer jinjing yang dikombinasikan dengan teknik pengenalan pola kemometrik PCA dan PLSDA. Analisis total flavonoid menunjukkan daun jati belanda berumur 1, 2, dan 3 bulan memiliki keragaman mutu senyawa aktif. Analsis PCA daun jati belanda dengan 7 sumber lampu menggunakan 2 PC pertama mampu menjelaskan 94% dari keragaman total (PC1 86% dan PC2 8%). Kombinasi 3 lampu (LED hijau, LED biru, dan LED biru-ungu) memberikan kesamaan pola plot skor PCA seperti pada analisis menggunakan 7 lampu LED. Analisis PLSDA dengan 7 lampu LED menghasilkan 3 model, yaitu model PLSDA umur 1 bulan (R2 = 0.9674), 2 bulan (R2 = 0.8781), dan 3 bulan (R2 = 0.9430). Model tersebut telah berhasil memprediksi sampel daun berumur 1 bulan. Model PLSDA 7 lampu masih lebih baik daripada model PLSDA dengan 3 lampu jika dilihat dari indikator kebaikan pemodelan (nilai R2, RMSEC, RMSEP) yang didapatkan. Model PLSDA daun dengan 3 sumber lampu (LED hijau, LED biru, LED biru-ungu) masih cukup sensitif untuk mengklasifikasikan dan memprediksi sampel yang diujikan.
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Judul: Kendali Mutu Daun Jati Belanda (Guazuma ulmifolia) Menggunakan Pengolahan Citra dan Teknik Pengenalan Pola secara Kemometrik
Abstrak: Quality of medicinal plants affects the quality of the herbs. The quality of medicinal plant, as jati belanda leaf (Guazuma ulmifolia) can be determined using image processing. The objectives of the research were to make spectral imaging as a method for quality control of jati belanda leaves by evaluating the quality based on various harvesting and combined with chemometric pattern recognition techniques (PCA and PLSDA). Jati belanda leaf image with various qualities were reconstructed as reflection spectrum using Wiener estimation. Goodness of spectrum reconstruction was presented from root-mean-square-error value of 36.65 % and goodness-of-fit coefficient value of 0.9576. The preprocessing technique was applied to the reflection spectra to get the best classification and prediction model. PCA analysis on the jati belanda leaves with data preprocessing using two first principal component (PC) was 100% able of the total variants in the data (PC1 92%, PC2 6%, PC3 1%, PC4 1%). PLSDA analysis produced 3 models. The models were sufficiently successful in differentiating the quality of jati belanda leaves.
Keyword: quality control, PLSDA, PCA, jati belanda, image processing

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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