Judul: Penerapan metode pemangkasan  dalam CART (Classification and Regression Tree) studi kasus : Pendugaan status gizi anak di Kecamatan Bogor Timur
Abstrak: CART (Classification and Regression Tree) merupakan metode eksplorasi data yang mampu menganalisis hubungan kausal antara peubah tidak bebas dan peubah bebas dalam jumlah data yang berukuran besar dan komplek yang terdiri dari data kategorik (nominal dan ordinal) dan pengukuran (interval dan rasio). CART merupakan metode yang sangat tepat dalam penelusuran peubalı penyebab (penjelas). Penerapan penelusuran peubah penyebab dalam penelitian ini untuk menyelesaikan permasalahan pendugaan status gizi anak. Penerapan metode pemangkasan dalam CART bermanfaat untuk menghindari terjadinya over fitting dan under fitting dalam membentuk pohon regresi. Penerapan ini menggunakan data status gizi anak sebelum dan sesudah pembinaan di Kecamatan Bogor Timur dengan tidak membandingkan kondisi data sebelum dan sesudah pembinaan. Pemangkasan paling baik yang dihasilkan, yaitu pemangkasan berdasarkan penurunan nilai devian tertinggi karena mempunyai metode yang lebih praktis dan dapat digunakan untuk contoh yang berukuran kecil, sedangkan pemangkasan berdasarkan penurunan nilai sisaan relatif penggantian ulang tertinggi dan selisih nilai tertinggi atau jarak terjauh antara nilai sisaan relatif validasi silang lebih akurat dalam penelusuran peubah penyebab dalam menduga peubah respon walaupun dengan ukuran contoh yang kecil. Penerapan model CART untuk menduga status gizi anak menghasilkan peubah penyebab yang konsisten dan logis, oleh karena itu model CART merupakan model yang tepat untuk digunakan dalam pendugaan status gizi anak.
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Judul: Penerapan Metode CART dan Agregat Bootstrap dalam Klasifikasi Status Gizi Balita Di Kecamatan Taman Sari, Kabupaten Bogor.
Abstrak: Nutrition problem is a multidimensional problem that affect health and productivity of Indonesian society. The number of short nutritional status (stunting) and high malnutrition is a serious health problem because it picturizes life for the next 100 years. About 90% of the short children problems in the world occur in 36 countries, and the rank of Indonesia is number five. The purpose of this study is to determine the factors that affect the nutritional status of children and evaluate the stability of classification trees with bootstrap aggregating method.The research is conducted at Taman Sari subdistrict, Bogor with the number of samples 120 mothers who have toddlers. Statistical analysis used to analyze the factors that influence the nutritional status of children is the method of CART (Classification and Regression Tree). CART is a method of data exploration which uses decision tree technique. This study also applies bagging method (bootstrap aggrergating) to evaluate the stability of classification trees generated by CART. The results of the classification tree formed produces optimum tree with eight terminal nodes. Explanatory variables into the main node is the nutritional behavior. Level of accuracy for the CART method was 69.17%.The percentage of the classification on the delimitation of the best z using z-score -2.5 SD with level of accuracy 76.67% and 88.33%, and z-score -3 SDwith level of accuracy 73.33% and 79.17%. Bagging method has been able to evaluate the stability of classification trees by 79.28%.
Keyword: bootstrap aggregating, CART, the nutritional status of children

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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