Judul: Pembentukan Minimal Non-Redundant Association Rules Menggunakan Frequent Closed Itemsets pada Data Transaksi Swalayan
Abstrak: Teknik association rules mining di dalam data mining seringkali menghasilkan aturan asosiasi dalam jumlah banyak yang dapat mengandung aturan-aturan yang berulang, yaitu aturan-aturan yang memberikan informasi yang sama. Penelitian ini menggunakan teknik mining minimal non-redundant association rules untuk menghasilkan aturan asosiasi yang tidak berulang pada data transaksi pembelian barang di Sinar Mart Swalayan selama 2 bulan (1 Maret 2004 – 21 Mei 2004). Konsep closure dalam Galois connection diterapkan dalam teknik minimal non-redundant association rules mining untuk membentuk generators dan frequent closed itemsets menggunakan algoritma Close. Pada penelitian ini dilakukan pembentukan generators dan frequent closed itemsets dengan menggunakan empat nilai minimum support, yaitu 5 %, 2 %, 1 %, dan 0,5 % dari 23.631 transaksi yang ada. Berdasarkan generators dan frequent closed itemsets, dibentuk minimal non-redundant association rules menggunakan 11 nilai minimum confidence, yaitu 75 %, 70 %, 65 %, 60 %, 55 %, 50 %, 45 %, 40 %, 30 %, 20 %, dan 10 %.
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Judul: Pemangkasan aturan asosiasi menggunakan algoritma P - DS (Studi kasus: data transaksi pasar swalayan)
Abstrak: Data mining merupakan serangkaian proses ekstraksi infomasi atau pola yang penting dalam basis data berukuran besar. Teknik data mining yang sering digunakan untuk mencari hubungan menarik di antara item-item dalam suatu himpunan data adalah association rule mining. Teknik association rule mining seringkafi menghasilkan aturan asosiasi dalarn jumlah banyak. Penelitian yang diiakukan adalah menerapkan teknik pemangkasan aturan asosiasi menggunakan algoritma P-DS, untuk rnenemukan aturan asosiasi yang paling sesuai bagi pengguna.
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Judul: Heterologous Expression Of Endo-Β-Xylanase From Bacillus Pumilus Strain Bcrs-01 In Escherichia Coli.
Abstrak: Xylanases are glycoside hydrolase family 11 which depolymerise xylan in the plant cell wall, the most excessive form of hemicellulose. Endo-β-xylanases (EC 3.2.1.8) are most important to breakdown β-1,4-glicoside bond of xylan to produce disaccaride xyloolygosaccaride (XOs) and xylose (monomer). Bovine rumen fluids have potential to obtain endo-β-xylanase produced of bacteria. The objectives of this study were to obtain xylanase producing bacteria and to express xynA gene encoding endo-β-xylanase from bacterium in Escherichia coli. Twenty nine isolate bacteria have been succesfully isolated from bovine rumen fluid in agar medium containing birchwood xylan. Isolate BCRS-01 bacterium was previously screened for the high production of xylanase. Based on 16S rRNA gene sequence analysis, BCRS-01 showed high similarity (99%) to Bacillus pumilus (accession number NR043241). The crude xylanase had optimal activity at 55oC, pH 7.0. Furthermore, the crude xylanase exhibited broad pH stability from 4.0 to 10.0 and remained more than 60% and 40% of its activity after incubation at pH 4.0 until 10.0, respectively for 60 min. It also showed a stability at temperature 25-50oC since it retained 80% and 50% of its activity when incubated at 50oC or 30 and 60 min, respectively. The xylanase activity was strongly inhibited by Ca2+ and Cu2+ at concentration 10 mM, and as little as 1 mM for Mn2+. Therefore, this xylanase has potentially used as additive feeds in animal feed industry. The DNA sequence xynA gene encoded endo-β-xylanase was amplified and cloned into the expression vector pET-15by under the control of T7 promoter. The recombinant protein had succesfully expressed in Escherichia coli BL21 (DE3) pLysS. A protein recombinant of approximately, 26.7 kDa was observed on the SDS-PAGE analysis. Crude extract of recombinant endo-β-xylanase demonstrated activity of enzyme at 56 U mL-1 using birchwood xylan as a substrate at 55oC for 10 min.
Keyword: Bacillus pumilus, bovine rumen fluid, endo-β-xylanase, heterologous expression.