Judul: Perbandingan Kinerja Pemilihan Fitur Chi-square Dan Singular Value Decomposition Sistem Temu Kembali Dokumen Tumbuhan Obat
Abstrak: This study analyzes the performance of the chi-square feature selection and Singular Value Decomposition (SVD) document retrieval system medicinal plants. The method is to find an effective document retrieval system based on queries to produce documents relevant to the user. Chi-square selection techniques make the selection based on the features that are important words that are used to create a vector space models. The model consists of several documents represented as vectors of the frequency of occurrence of features. SVD feature selection technique using key words found in each document. Important words become terms of the term-document matrix. Indonesian language document medicinal plants totaling 132 documents used in the chi-square retrieval and SVD. Retrieval and SVD chi-square test with 29 non-semantic and semantic query. The result is a comparison of the performance of the retrieval of both methods on non-semantic and semantic query.
Keyword: chi square, singular value decomposition, information retrieval, eature selection, medicinal plants

Judul: Performance Comparison of Medicinal Plant Journal Information Retrieval System Using Vector Space Model and Okapi BM25 Method
Abstrak: Dokumen tanaman obat merupakan salah satu hasil penelitian yang dapat digunakan sebagai landasan penelitian berikutnya maupun sumber informasi yang relevan. Semakin banyaknya dokumen publikasi mengenai tanaman obat maka dibutuhkan metode text mining untuk mengektraksi informasi sesuai kebutuhan pengguna. Temu kembali informasi merupakan salah satu bidang ilmu di text mining yang digunakan untuk menemukembalikan informasi yang relevan sesuai kebutuhan pengguna pada kumpulan dokumen, dalam hal ini adalah jurnal tanaman obat pada laman www.jamumedicine.com. Untuk melakukan proses temu kembali informasi, terdapat beberapa jenis metode yang bisa digunakan beberapa diantaranya adalah Vector Space Model (VSM) dan Okapi BM25. Vector Space Model merepresentasikan setiap dokumen menjadi vektor di dalam ruang vektor. Dalam vektor ini, setiap dimensi mewakili kata-kata unik yang terdapat di dalam korpus sedangkan Okapi BM25 menghitung skor relevansi antara dokumen dan kueri dengan mempertimbangkan beberapa faktor, seperti frekuensi kata dalam dokumen, frekuensi kata dalam kueri, panjang dokumen, panjang rata-rata dokumen dalam koleksi dokumen, dan jumlah total dokumen dalam koleksi. Berdasarkan penelitian sebelumnya metode BM25 lebih baik dibandingkan dengan metode Vector Space Model. Namun, karena perbedaan data dan ruang lingkup penelitian maka perbandingan ini perlu dilakukan kembali untuk menguji efektivitas kedua metode tersebut. Setelah mengevaluasi perbandingan temu kembali informasi kedua metode maka diperoleh hasil bahwa metode vector space model efektif pada kueri satu kata dan BM25 efektif pada kueri dua dan tiga kata. Kesimpulan dari penelitian ini adalah vector space model cocok diterapkan pada kueri satu kata dan BM25 cocok digunakan untuk kueri dua kata atau lebih. Kedua metode disarankan untuk diimplementasikan bersamaan pada www.jamumedicine.com agar mendapat hasil yang optimal.
Keyword: Information retrieval, Medicinal plant documents, Okapi BM25, Text Mining, Vector Space Model

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