Judul: Deteksi Anomali Pada Transaksi Kartu Kredit Menggunakan Adaptive Synthetic Resampling(ADASYN) dan Support Vector Machine (SVM)
Abstrak: Munculnya anomali atau transaksi penipuan akibat banyaknya transaksi yang terjadi pada kartu kredit, menjadikan perlunya deteksi anomali pada transaksi kartu kredit agar tidak merugikan pihak nasabah maupun bank. Salah satu kendala deteksi anomali tersebut adalah pembentukan model matematis yaitu dataset yang memiliki distribusi kelas yang tidak seimbang. Salah satu contohnya adalah transaksi anomali kartu kredit yang mana jumlahnya lebih sedikit dibandingkan data transaksi normal yang terjadi. Walaupun transaksi penipuan hanya berjumlah sedikit, namun memiliki pengaruh yang sangat besar. Maka dari itu, diperlukan model untuk melakukan screening untuk memperkirakan transaksi penipuan. Tujuan penelitian ini adalah untuk menghasilkan data latih yang ideal dari dataset yang tidak seimbang menggunakan Adaptive Synthetic Sampling (ADASYN) agar dapat digunakan untuk proses pelatihan model Support Vector Machine (SVM). Hasil penelitian menunjukkan bahwa model SVM yang dilatih dengan mengunakan data SV yang diseimbangkan dengan ADASYN mampu mengklasifikasikan transaksi anomali dengan sangat baik., There are anomalies or fraudulent transactions due to the large number of transactions that occur on credit cards, making it necessary to detect anomalies in credit card transactions so as not to harm the customer or bank. One of the obstacles in detecting these anomalies is the formation of mathematical models, namely datasets that have an unbalanced class distribution. One example is anomalous credit card transactions, which are fewer in number than normal transaction data. Although the transactions are only small, they have a very large impact. Therefore, a model is needed to perform screening to estimate fraudulent transactions. The purpose of this research is to produce ideal training data from an unbalanced dataset using Adaptive Synthetic Sampling (ADASYN) so that it can be used for the Support Vector Machine (SVM) model training process. The results showed that the SVM model trained using SV data balanced with ADASYN was able to classify anomalous transactions very well
Keyword: Adaptive Synthetic Sampling, transaksi kartu kredit, support vector  machine

Judul: Deteksi Penipuan Kartu Kredit menggunakan Support Vector Machine dengan Optimasi Grid Search dan Genetic Algorithm
Abstrak: Transaksi kartu kredit mengalami peningkatan yang signifikan setiap tahunnya. Seiring dengan meningkatnya pemakaian kartu kredit maka meningkat pula risiko tindak penipuan oleh oknum yang tidak bertanggung jawab. Kemungkinan transaksi penipuan kartu kredit dapat terdeteksi melalui bantuan pembelajaran mesin. Permasalahan utama dalam mengolah data transaksi ialah dimensinya yang besar, kelas yang tidak seimbang, dan diperlukan proses pendeteksian dengan waktu komputasi yang singkat. Maka dari itu dibutuhkan model serta algoritma optimasi yang tepat untuk mengatasi permasalahan tersebut. Tujuan penelitian ini adalah membangun model pendeteksian transaksi penipuan kartu kredit yang mampu menghasilkan performa baik serta waktu komputasi singkat menggunakan metode support vector machine (SVM) dengan optimasi grid search dan genetic algorithm. Dari lima model yang dibangun, diperoleh bahwa model SVM menggunakan dataset SV dengan grid search sebagai teknik optimasi hyperparameter mampu melakukan pendeteksian dengan baik dan waktu komputasi yang singkat. Model berikut memiliki nilai F2-measure terbaik yaitu 99.96%.
Keyword: support vector machine, genetic algorithm, grid search

Judul: Extracellular Expression of thermostable Geobacillus stearothermophilus T1.2RQ Lipase for Biodiesel Production
Abstrak: The extracellular expression of enzymes in an excellent secretion host such as Bacillus subtilis is a useful strategy for making enzymes of industrial significance more affordable by lowering the cost of its downstream processing. Lipases are a category of hydrolases that catalyze the hydrolysis of triglycerides to glycerol and free fatty acids. Also, lipases catalyze the hydrolysis and transesterification of other esters as well as the synthesis of esters. They can perform very specific biotransformation reactions and are widely used in food, organic synthesis, detergents, cosmetic, and pharmaceutical industries. Geobacillus stearothermophilus T1.2RQ lipase is an industrially-desired thermostable lipolytic enzyme with an excellent hydrolytic and transesterification activity. This study aimed to express T1.2RQ lipase, in B. subtilis WB800 and ensure its secretion into the extracellular medium. Three signal peptides (AmyQ, Epr, LipA) and two promoters (Pgrac01 and Pgrac100) were used in the secretory-expression of T1.2RQ lipase, based on five constructed expression vectors constructed by restriction cloning and PCR mutagenesis. Sangers sequencing was used to verify constructs to ensure they are in the correct reading frame. Recombinants vectors, pHT43 (plasmid control), pHT43-T1.2RQ, pHT43- T1.2RQ_AmyQ, pHT43-T1.2RQ_Epr, and pHT43-T1.2RQ_LipA, were transformed by electroporation into Bacillus subtilis WB800. The electroporation was successful with the optimum condition of 2500V, 200 ohms, 25µF, and 5milliseconds. Recombinant B. subtilis pHT43 (negative control) and pHT43-T1.2RQlip + signal peptides were streaked on the lipidic agar, LA+TBN. All four recombinants, including the negative control (B. subtilis WB800-pHT43), produced clear zones on the TBN agar plate after overnight incubation (fig 2), indicating the presence of a lipolytic enzyme in all of the recombinant B. subtilis cells. pHT43-T1.2RQlip + signal peptides (AmyQ, Epr, and LipA) have clear zones with significantly higher diameters than B. subtilis WB800-pHT43 (negative control). This phenomenon suggests that the recombinant thermostable lipase T1.2RQ introduced into these cells was successfully expressed, thereby increasing the lipolytic capability of its host cells T1.2RQ lipase was expressed in 50ml terrific broth medium (TB) and the expression induced with 1mM IPTG. Lipase activity assay using p-nitrophenyl esters showed that all three signal peptides directed the secretion of T1.2RQ lipase into the extracellular medium. Signal peptide, LipA, resulted in the highest extracellular activity of 5.6 U/mL, which corresponds to a 6-fold increase over the parent B. subtilis WB800 strain. Meanwhile, signal peptides, AmyQ and Epr produced 4.2 U/mL and 3.4 U/mL activity respectively. SDS-Zymogram analysis confirmed that T1.2RQ lipase was correctly processed and secreted in its original size of 44 kDa. An attempt to further increase lipase expression level by promoter optimization showed that, contrary to expectation, promoter Pgrac100 exhibited similar expression levels as the original Pgrac01. Nevertheless, the demonstration of the successful secretion of T1.2RQ lipase in this work confirms the latter as a promising approach for the industrial production of the enzyme
Keyword: Bacillus subtilis, Expression, Extracellular, Heterologous, Lipase, Thermostable