Judul: Deteksi Pencilan pada Data Titik Panas Menggunakan Clustering Berbasis Medoids
Abstrak: Forest fire is one of disasters which has a very adverse impact. Land and forest fires in Indonesia are caused by several factors, such as prolonged drought, human negligence and irresponsible parties who deliberately set fire to achieve certain goals. Hotspot is an indicator of forest fires. The purpose of this study is to detect outliers in hotspots in 2001 until 2012. Hotspot data were obtained from the NASA FIRM. The outlier detection was performed using medoid based clustering methods, namely PAM and CLARA. The result of PAM algorithm show that outliers occur in cluster k=17 with medoid 13,14,15,16 and 17. The result of CLARA algorithm show that outliers occur in cluster k = 19 with medoid 14,15,17 and 19. PAM and CLARA algorithm detect outliers in February, March, June, July and August. Clustering results are expected to assist the authorities in determining potential areas for forest fires prevention
Keyword: Bogor Agricultural University (IPB), outlier detection, hotspot, forest fires, k-medoids, clustering

Judul: Deteksi pencilan kontekstual pada data titik panas di Provinsi Riau menggunakan algoritme k-means
Abstrak: Kebakaran hutan merupakan salah satu permasalahan lingkungan yang terus berulang dan menjadi suatu ancaman terbesar bagi sumber daya hutan di Indonesia. Salah satu upaya pencegahan kebakaran hutan tersebut adalah dengan mengetahui penyebaran pengelompokan titik panas. Data titik panas yang diperoleh dengan cara penginderaan jauh menggunakan satelit sangat memungkinkan terjadi penyimpangan (pencilan). Penelitian ini bertujuan mendeteksi pencilan kontekstual pada data titik panas di Provinsi Riau dari tahun 2001 sampai 2009 berdasarkan konteks cuaca yaitu curah hujan. Pencilan kontekstual dideteksi menggunakan hasil clustering pada atribut frekuensi titik panas harian dan curah hujan. Metode yang digunakan adalah teknik clustering dengan algoritme k-means. Hasil menunjukkan bahwa jumlah pencilan kontekstual yang terdeteksi sebanyak 54 objek. Pencilan ini banyak terjadi pada bulan Februari, Maret, Juni, Juli, dan Agustus. Sebagian besar objek-objek yang terdeteksi sebagai pencilan merupakan titik panas yang frekuensi harian tinggi dengan curah hujan juga tinggi. Rata-rata dari pencilan kontekstual yang terdeteksi adalah sebesar 65.76 titik panas dengan curah hujan rata-rata 37.15 mm.
Keyword: clustering, contextual outlier, forest fire, hotspot, k-means

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