Judul: Aktivitas Antioksidan Ekstrak Etanol dan Fraksi Bekatul dengan Metode 1,1-difenil-2-pikrilhidrazil
Abstrak: Bekatul adalah bagian kulit beras yang dihasilkan pada proses penggilingan padi. Bekatul mengandung komponen bioaktif seperti tokoferol, tokotrienol, orizanol, β-karotein, serat, asam lemak, protein dan vitamin. Tujuan penelitian adalah menentukan aktivitas antioksidan, kandungan total fenolik dan flavonoid yang terdapat pada ekstrak etanol bekatul dan fraksi-fraksinya. Ekstraksi bekatul dilakukan dengan metode maserasi menggunakan pelarut etanol 95% dan selanjutnya difraksinasi dengan pelarut n-heksana, diklorometana, etil aseat, dan air. Nilai rendemen tertinggi terdapat pada ekstrak etanol bekatul sebesar 4,94%. Hasil uji fitokimia pada ekstrak kasar menunjukkan bahwa bekatul mengandung senyawa alkaloid, tanin, saponin, flavonoid, dan steroid. Aktivitas antioksidan tertinggi terdapat pada ekstrak etanol bekatul dengan nilai IC50 sebesar 29,27 μg/mL dan termasuk antioksidan kuat. Kadar total fenolik tertinggi terdapat pada fraksi air yaitu sebesar 34,76 mg GAE/g, sedangkan kadar total flavonoid tertinggi pada fraksi n-heksana yaitu sebesar 40,82 mg QE/g.
Keyword: bekatul, fraksinasi, fenolik, flavonoid, DPPH

Judul: Aktivitas Antioksidan Hasil Fraksinasi Ekstrak Etanol Angkak dan Bekatul dengan Metode Reduksi Ferri (FRAP)
Abstrak: Penyakit degeneratif merupakan penyebab kematian tertinggi di Indonesia. Salah satu cara pencegahannya adalah dengan konsumsi antioksidan. Angkak dan bekatul merupakan sumber antioksidan yang telah banyak diketahui. Tujuan penelitian ini adalah memperoleh fraksi yang memiliki aktivitas antioksidan tertinggi. Ekstrak etanol difraksinasi dengan partisi cair-cair sehingga diperoleh empat fraksi, yaitu fraksi n-heksana, fraksi diklorometana, fraksi etil asetat, dan fraksi air. Uji aktivitas antioksidan dilakukan dengan metode ferric reducing antioxidant power (FRAP). Hasil uji menunjukkan bahwa semua fraksi pada angkak dan bekatul memiliki potensi sebagai antioksidan. Aktivitas antioksidan tertinggi angkak dan bekatul sama-sama terdapat pada fraksi etil asetat, yaitu sebesar 190.84 mg TE/g fraksi pada angkak dan 163.74 mg TE/g fraksi pada bekatul. Hasil uji korelasi menunjukkan bahwa aktivitas antioksidan angkak berkorelasi dengan total fenolik dan total flavonoidnya, sedangkan aktivitas antioksidan bekatul hanya berkorelasi terhadap total flavonoidnya.
Keyword: angkak, bekatul, fenolik, flavonoid, FRAP

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