Judul: Pemodelan Biplot pada Klasifikasi Fragmen Metagenom dengan K-Mers Sebagai Ekstraksi Ciri Dan Probabilistic Neural Network Sebagai Classifier
Abstrak: Metagenomics is the study of the genetic material taken directly from the organism's source environment by performing deoxyribonucleic acid sequencing procedure. Sequencing was performed on a set of genomes that have been mixed with a variety of other organisms in the environment. This led to the identification of the organism is required to prevent fragment assembly error between organisms. This study objectives to classify metagenome fragments at the genus level with Probabilistic Neural Network algorithms and k-mers as the features extraction. Biplot modelling is used to reduce features of the k-mers results that have dimensions large enough. This study uses 3 genuses of microorganisms which are divided into 2 dataset groups, namely known organisms and unknown organisms. The length of fragments used for each dataset is 500 bp, 1 kbp, 5 kbp, and 10 kbp. From the results of this study, the best accuracy for the known organisms was 98.10% and 92.80% for unknown organisms. Biplot modelling managed to reduce 68.75% fragment features with classification efficiency of 12%.
Keyword: Bogor Agricultural University (IPB), PNN, biplot, k-mers, DNA, metagenome

Judul: Klasifikasi Fragmen Metagenom Menggunakan Ekstraksi Spaced N mers dan Probabilistic Neural Network sebagai Classifier
Abstrak: Metagenomika merupakan cabang genetika yang secara khusus ditujukan untuk mempelajari materi genetik yang diambil langsung dari sampel lingkungan, diikuti dengan menganalisis informasi genetika tersebut. Proses sekuensing dari sampel lingkungan menghasilkan fragmen-fragmen pendek yang berasal dari beberapa mikroorganisme yang terdapat pada sampel tersebut. Kondisi seperti ini menyebabkan proses perakitan fragmen menjadi tidak akurat, yaitu dengan dimungkinkannya terbentuknya cymeric contigs. Keberadaan cymeric contigs ini dapat diminimalkan dengan melakukan binning. Proses binning dapat dilakukan dengan pengklusteran atau pengklasifikasian. Penelitian ini dilakukan menggunakan metode probabilistic neural network untuk proses klasifikasi dan spaced n-mers untuk ekstraksi fiturnya karena sudah terbukti akurat dan menghasilkan akurasi yang baik. Data yang dipakai mempunyai panjang fragmen 500 bp, 1000 bp, 5000 bp, dan nilai n-mers yang dipakai adalah 3. Akurasi yang terbaik dihasilkan dengan menggunakan nilai smoothing parameter 11 untuk pengujian organisme dikenal. Selanjutnya pengujian dengan organisme tidak dikenal menghasilkan akurasi sebesar 64.40% untuk panjang fragmen 500 bp, 68.60% untuk panjang fragmen 1000 bp, 69.62% untuk panjang fragmen 5000 bp.
Keyword: binning, classification, metagenome, probabilistic neural network

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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