Judul: Penggunaan mikroorganisme Hansenula anomala dan Candida utilis dala produksi komponen citarasa(Flavor)
Abstrak: Mikroorganisme telah digunakan sejak dahulu kala pada produk-produk makanan dan minuman fermentasi. Kemampuan mikroba untuk mensintesis komponen citarasa pada makanan maupun minuman fermentasi merupakan dasar bagi perkembangan produksi citarasa melalui bioteknologi. Produksi komponen citarasa alami dari mikroba merupakan salah satu alternatif pengganti senyawa citarasa kimiawi atau senyawa citarasa dari tumbuh-tumbuhan. Dalam penelitian ini, komponen citarasa mula-mula diproduksi menggunakan empat jenis mikroba yaitu Geotricum candidum, Penicillium italicum, Hansenula anomala dan Candida utilis yang ditumbuhkan pada medium air kelapa, hati nenas dan Potato Dextrose Broth. Dari hasil penelitian tersebut dipilih dua jenis mikroba yaitu H. anomala dan C. utilis dengan medium air kelapa dan hati nenas yang digunakan untuk penelitian selanjutnya. Analisis yang dilakukan adalah dengan mengukur total masa sel, total asam, kadar alkohol, kadar gula pereduksi, total ester, total Volatile Reducing Substance (VRS), kadar aldehid, penilaian organoleptik dan analisis profil komponen volatil dengan gas kromatografi. ...
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Judul: Analisa komponen flavor yang dihasilkan oleh Hansenula anomala pada substrst air kelapa
Abstrak: Hansenula anomala diketahui dapat menghasilkan ester terutama etil asetat. Telah dilaporkan bahwa H. ano- mala yang ditumbuhkan pada limbah air kelapa berpotensi dalam menghasilkan flavor. Dalam penelitian ini dipelajari produksi komponen flavor oleh Hansenula anomala yang ditumbuhkan pada substrat air kelapa. Pada penelitian pendahuluan kultur H. anomala ditumbuhkan pada pH 4.3 dengan perlakuan masa inkubasi (3, 6, 9 dan 12 hari), kadar gula awal (rendah: 7.68 mg/ml dan tinggi: 17.68 mg/ml) dan tanpa/dengan penamba- han gula selama fermentasi. Analisis selama fermentasi meliputi kadar gula pereduksi, jumlah mikroba, total asam tertitrasi, komponen volatil pereduksi dan kadar ester. Kadar gula awal ternyata mempengaruhi pertumbuhan mikro- ba, produksi asam, komponen volatil pereduksi dan ester sedangkan penambahan gula selama fermentasi tidak berpengaruh nyata. Komponen flavor yang dihasilkan mencapai optimum pada masa inkubasi 9 hari, kadar gula awal tinggi dan tanpa penambahan gula selama fermentasi. ...
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Judul: The Construction of Greedy SVP LLL Algorithm
Abstrak: A lattice is a set of all integer linear combination of a set of linearly independent vectors in ℝ𝑛���. The independent vectors are called bases of lattice. Any lattice can be generated from many bases, and these bases have the same cardinality. In the lattice, the most fundamental and renowned problem is the Shortest Vector Problem (SVP). SVP is a tracking problem of the shortest nonzero vector in a lattice with equivalent bases. In two dimensions, SVP problem has resolved exactly by Gauss’ algorithm. When the lattice dimension is higher than two, A.K. Lenstra, H.W. Lenstra and L. Lovasz gave a LLL algorithm to compute approximation of nonzero shortest vector in the lattice. Reduced bases solution obtained from LLL algorithm still be an approximation and has polynomial running time of arbitrary dimension which large enough. In 1994, Schnoor and Euchner modified this LLL algorithm as a new variant which later was named deep insertion LLL algorithm. This algorithm is a modified version of the LLL algorithm to the terms of the exchange step to improve the accuracy of output of LLL reduced bases and applying it to the subset sum problem. The purpose of this research are: (1) Reconstruct the LLL algorithm and deep insertion LLL algorithm using a geometric approach. (2) Construct a greedy SVP LLL algorithm. (3) Implement the three algorithms in a symbolic programming language, and evaluate them experimentally. A bases ℬ=[𝐛���1,𝐛���2,…,𝐛���𝑛���] in ℝ𝑚��� is called reduced LLL with parameter 𝛿��� if satisfies: (a) |𝜇���𝑗���𝑖���|≤12, for every integer 𝑖���,𝑗��� with 1≤𝑖���<𝑗���<𝑛���. (b)𝛿���‖𝜋���𝑗���(𝐛���𝑗���)‖2≤‖𝜋���𝑗���(𝐛���𝑗���+1)‖2, for 𝑗���=1,2,…,𝑛���−1,where 𝛿��� is a reduced parameter of real numbers with 14<𝛿���<1. The first requirement is the reduced basis 𝛿��� must “nearly orthogonal” and in its computation case, this requirement can be reached out by using the Gram-Schmidt’s orthogonalization. While the second requirement is called exchange step, or used to called as Lovasz condition. By using both of these requirements, then they establish the LLL algorithm. Then, Schnoor and Euchner modify the LLL algorithm based on the requirements of the exchange step called the deep insertion LLL algorithm, where the exchange step is based on the comparison of the projected vector in orthogonal complement [𝐛���1,𝐛���2,…,𝐛���𝑘���−1]⊥ after j-th reduction. To construct greedy SVP LLL algorithm, the requirements of the exchange step is based on purely by comparing norm of lattice 𝐛���𝑗��� with norm lattice 𝐛���𝑖��� for 𝑖���=1,2,3…,𝑗���−1. The process of insertion reduced vector after the exchange step also has done greedily. Then, we calculate the number of arithmetic operation in greedy SVP LLL algorithm for further analysis. The result of our exprimentation for three algorithms on the certain matrix size shows that the running time of the three algorithms increases propotional to the size of the matrix. The result also shows that by using 𝛿���=34 for the LLL algorithm and the deep insertion LLL algorithm, and the greedy SVP LLL algorithm which is a new variant made by using no parameter of 𝛿���, outperform of the other of two previous algorithm in terms of speed with the same output.
Keyword: LLL algorithm, LLL deep insertion algorithm, greedy SVP LLL algorithm