Judul: Penerapan Algoritme Prefixspan dan Clospan untuk Mencari Pola Sekuensial pada Data Peminjaman Buku di Perpustakaan IPB
Abstrak: Library is an important facility in university. From the library data we can obtain various information, such as patterns of borrowing books by library users. This study aims to determine the sequential patterns of IPB’s library book loan data using two algorithms namely Clospan and Prefixspan. This study used the dataset with the size ranging from 50 to 4.140 and minimum support ranging from 5% to 15%. The experimental results show that the larger dataset and the minimum support used, Clospan algorithm has better performance than Prefixspan. In addition, the results of two sequential pattern algorithms which shows the relationships between the book code 027 (general libraries) with 820 (literature) books, 631 (farm management,agronomy, andhorticulture) books with book code 636 (animal husbandry and breeding in general), and 631 (farm management,agronomy, andhorticulture) to 658 (business management, administration, and commercial organization).
Keyword: Clospan, Prefixspan, library circulation data, sequential pattern

Judul: Penerapan Algoritme Prefixspan dan GSP untuk Mencari Pola Sekuensial pada Data Peminjaman Buku di Perpustakaan IPB
Abstrak: IPB's library as a learning support unit for student has an important role such as book lending service. The data obtained from the circulation transaction will generate a certain pattern of books that are being borrowed by library user. This research applies the prefixspan algorithm and generalized sequential pattern (GSP) algorithm to obtain a sequential pattern. The amount of data used ranges from 50 to 4104 with the value of minimum support ranges from 5% to 20%. The results show that the GSP algorithm works better on high minimum support while prefixspan algorithm works better in low minimum support. The sequential patterns generated from the two algorithms show the relationships between item: book code 820 (literature) with 027 (general), book code 631 (agriculture) with 658 (management, administration, commercial organizations), and book code 631 with 636 (husbandry). The most frequently borrowed book from the entire dataset is the book code 658.
Keyword: prefixspan, sequential pattern, generalized sequential patterns (GSP)

Judul: Pengaruh Konsentrasi Katalis Methyl Ester Sulfonic Acid Terhadap Sifat Fisikokimia Gliserol Ester Oleat yang Dihasilkan
Abstrak: Glycerol is a by-product from palm olein biodiesel industry which could be value-added to obtain various products. One of the alternatives is to modify glycerol become glycerol ester oleat. Before processing, glycerol was first refined using 5% (v/v) phosphoric acid 85%. The refinery showed that glycerol content was increased from 49% to 80%. Glycerol was then esterified with oleic acid and catalyst methyl ester sulfonic acid (MESA) to obtain glycerol ester. Esterification was conducted at 240°C and nitrogen atmosphere using 200 rpm of mixing for 90 minutes. The best catalyst concentration used in esterification process is at 0,5% and resulting glycerol ester oleat with acid number 48,07 mg KOH/g sample, density of 0,9124 g/cm3, viscosity 68,32 cP (25°C), kinematic viscosity 36 cSt (40°C), flash point 230°C and pour point -15°C.
Keyword: glycerol ester, glycerol