Judul: Model Dinamika Opini Konsumen dalam Pembelian Produk dengan Pemasaran Sistematis/Acak: Studi Kasus Koneksi Tidak Lengkap
Abstrak: Manusia sebagai mahluk sosial berinteraksi dengan manusia lainnya. Dalam aktivitas sehari-hari manusia adalah konsumen yang tak lepas dari proses pengambilan keputusan. Interaksi antar konsumen akan menimbulkan dinamika opini yang berpengaruh dalam pengambilan keputusan konsumen. Selain hasil dari interaksi juga akan dipengaruhi oleh bagaimana produk atau jasa tersebut dipasarkan. Penelitian ini akan berfokus kepada pengaruh sistem pemasaran dalam proses pengambilan keputusan konsumen. Dengan pemodelan berbasis agen, penelitian ini menggunakan beberapa parameter yang berpengaruh diantaranya adalah atribut agen, index of perception, fungsi pemasaran, strength of advertising dari produk. Strength of advertising dari sebuah sistem pemasaran mempengaruhi jumlah produk yang terjual, semakin besar nilainya maka semakin banyak produk yang terjual. Kasus dengan koneksi antar agen tidak lengkap menunjukan bahwa sistem pemasaran secara sistematis cenderung lebih unggul dibandingkan dengan sistem pemasaran secara acak. Metode perhitungan dengan entropi Shannon digunakan untuk menganalisis sifat fisis model pengambilan keputusan konsumen.
Keyword: dinamika opini, entropi Shannon, pemodelan berbasis agen

Judul: Analisis Sifat Fisis Model Dinamika Opini Berbasis Agent-based Model
Abstrak: Dalam aktivitas sehari-hari manusia berinteraksi dengan lingkungan dalam berbagai bentuk. Setiap individu memiliki karakter dan budaya yang berbeda-beda. Interaksi antar individu akan menimbulkan pembentukan opini publik yang beragam sehingga terbentuklah dinamika opini. Penelitian ini akan fokus pada pengamatan interaksi antar individu untuk menentukan metode pengambilan keputusan. Pemodelan matematika dan fisika serta metode komputasi sebagai alat bantu terutama Agent-based Model untuk mengetahui penyebaran dan dinamika opini masyarakat. Dengan pendekatan agen, dinamika opini masyarakat dapat dipelajari secara nyata untuk berbagai kepentingan. Dalam penelitian ini akan digunakan beberapa parameter yang berpengaruh terhadap perubahan opini individu diantaranya adalah atribut individu, pengaruh lingkungan dan arus informasi. Untuk membantu menganalisis sifat fisis model dinamika opini digunakan metode perhitungan entropi shannon.
Keyword: Dinamika opini, Agent-based Model, Entropi shannon

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