Judul: Karakteristik Fisik Kimia dan Mikrobiologi Kefir Susu Kambing dengan Penambahan Ekstrak Kulit Manggis Komersial
Abstrak: Kefir is one of the fermented milk products. The supplementation of mangosteen pericarp extract as source of antioxidant was aimed to increase the functionality of fermented milk products. The extract of mangosteen pericarp was purchased from PT. Haldin Pacific Semesta. The purpose of this research was to study the physical, chemical, and organoleptical characteristics of the goat’s milk kefir with and without addition of mangosteen pericarp extract. The results showed that antioxidant activity on the extract of mangosteen pericrap had IC50 value about 20 482.5 ppm (2%). Supplementation of mangosteen pericarp extract affected significantly on viscosity, antioxidant activity, and parameters of hedonic test color, smell, and general appearance.
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Judul: Karakteristik Fisikokimia dan Aktivitas Antioksidan Kefir Susu Kambing Etawa dengan Penambahan Sari Kurma Sukari (Phoenix dactilyfera L)
Abstrak: Kefir adalah produk olahan susu yang difermentasi dengan mikroorganisme menguntungkan seperti bakteri asam laktat dan khamir. Kefir merupakan produk pangan fungsional yang dapat dimodifikasi melalui penambahan sari kurma (Phoenix dactilyfera L). Penelitian ini bertujuan untuk menganalisis karakteristik fisikokimia dan aktivitas antioksidan kefir susu kambing dengan penambahan konsentrasi sari buah kurma yang berbeda. Penelitian ini menggunakan rancangan acak lengkap (RAL) pada tiga konsentrasi penambahan sari kurma yang berbeda, yakni 0% (kontrol), 12,5%, dan 25%. Karakteristik fisikokimia yang dianalisis meliputi aw, pH, total asam tertitrasi (TAT), dan viskositas. Nilai aktivitas antioksidan pada penelitian ini juga dianalisis. Hasil penelitian menunjukkan bahwa penambahan sari kurma pada kefir susu kambing berpengaruh nyata (p<0,05) terhadap nilai pH, TAT, viskositas dan peningkatan aktivitas serta kapasitas antioksidan. Sementara itu, penambahan sari kurma pada kefir susu kambing tidak menunjukkan adanya perbedaan yang nyata (p<0,05) terhadap nilai aw. Kesimpulannya penambahan sari kurma pada kefir susu kambing meningkatkan aktivitas antioksidan tanpa menurunkan mutu fisikokimianya.
Keyword: Antioxidant, goat milk, Physicochemical, Date fruit extract, Kefir

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