Judul: Kendali Mutu Daun Kumis Kucing (Orthosiphon stamineus) Menggunakan Pengolahan Citra Dan Teknik Pengenalan Pola Secara Kemometrik
Abstrak: Kumis kucing (Orthosiphon stamineus) is one of medicinal plants that widely used as a traditional medicine. This research aims to use the spectral imaging as a method to quality control of kumis kucing leaves with diversity of quality based on the different from 3 areas of the plant that is correlated with the intensity of leaf color and pattern recognition techniques combine with chemometric PCA and PLSDA. Analysis of thin-layer chromatography with software image J shows the difference of quality active compound kumis kucing from 3 areas is Cigombong, Nagrak, and Pacet. The best standard model and polynomial using polynomial orde 2 (term 7). Samples from Nagrak have better quality than other areas. Model PCA produces 97% of the value of PC 1 and PC 2 3%. PLSDA analysis produces 3 models, namely models PLSDA from Cigombong (R2 kalibrasi= 0.8395, R2 prediksi= 0.8051), Nagrak (R2 kalibrasi= 0.8185, R2 prediksi= 0.7779), dan Pacet (R2 kalibrasi= 0.7603, R2 prediksi= 0.7392). This model has successfully predicted the kumis kucing leaves to approach the quality of different areas of the plant.
Keyword: Bogor Agricultural University, spectral imaging, quality control, PLSDA, PCA, kumis kucing

Judul: Autentikasi Kumis Kucing (Orthosiphon aristatus) dari Babadotan dan Tekelan dengan Spektrum Ultraviolet-Tampak dan Partial Least Square Regression.
Abstrak: Kumis kucing (Orthosiphon aristatus) adalah tanaman obat yang banyak digunakan dalam mengobati berbagai penyakit. Daun kumis kucing memiliki kemiripan morfologi dengan daun tekelan dan babadotan sehingga dimungkinkan terjadinya pemalsuan bahan baku kumis kucing. Tujuan penelitian ini adalah mengembangkan metode analisis untuk identifikasi dan autentikasi kumis kucing dari babadotan dan tekelan menggunakan spektrum ultraviolet-tampak yang dikombinasikan dengan regresi PLS. Kisaran panjang gelombang yang digunakan untuk autentikasi adalah 210-500 nm. Prapemrosesan sinyal untuk data matriks spektrum ultraviolet-tampak dilakukan menggunakan transformasi detrending karena menghasilkan galat yang lebih kecil dibanding proses transformasi yang lain. Hasil yang didapat menunjukkan nilai koefisien determinasi (R2) di atas 0.9 untuk kalibrasi dan validasi. Nilai root mean square error calibration (RMSEC) yang sudah cukup rendah dan nilai root mean square error prediction (RMSEP) yang masih cukup tinggi menunjukkan bahwa model yang dikembangkan masih kurang baik dalam menentukan konsentrasi bahan pemalsu di dalam sampel.
Keyword: babadotan, kumis kucing, regresi PLS, spektrum UV-Vis, tekelan

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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