Judul: Perbandingan Metode Seleksi Fitur pada Spam Filter Menggunakan Klasifikasi Multinomial Naïve Bayes
Abstrak: Nowadays lots of unwanted email called spam may freely get into the inbox entry. Therefore spam filter software made to classify spam and non-spam email (ham) automatically. Naïve Bayes frequently used today as classification method for it simple and easy to be implemented. Naïve bayes has a good performance to classify multinomial document compared to multivariate Bernoulli when it comes to large vocabulary. Feature selection needed to improve classification model accuracy and make computation process more efficient. There are three feature selection methods used such as inverse document frequency (IDF), mutual information (MI), and chi-square. Based on accuracy level, the result of this study shows that MI is the best feature selection method with 93.77% accuracy and 9507 vocabulary as an identifier
Keyword: Bogor Agricultural University (IPB), spam filter, multinomial Naïve Bayes, feature selection

Judul: Metode Smoothing dalam Naïve Bayes untuk Klasifikasi Email Spam
Abstrak: The presence of spam in email lead research on the development of software to classify email spam filter increases. Naïve Bayes is widely used as classification function by spam filter developer. Smoothing method on Naïve Bayes classification function that has been commonly used, namely Add-One smoothing or Laplace smoothing. There are another methods such as Jelinek-Mercer smoothing, Dirichlet smoothing, Absolute Discounting smoothing, and Two –Stage which allegedly able to improve classification accuracy exceeds Laplace smoothing. The experimental results shown accuracy for Naïve Bayes classification function using Laplace smoothing method is 93.72% lower than other smoothing methods which accuration results more than 94%. Naïve Bayes classification function which using Dirichlet smoothing method that gives the best results with accuracy 94.82%.
Keyword: Bogor Agricultural University (IPB), spam filter, naïve bayes smoothing method, accuration

Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
Keyword: