Judul: Aktivitas Antioksidan dan Kandungan Total Fenolik serta Flavonoid Ekstrak Etanol Tanaman Krokot (Portulaca grandiflora Hook.)
Abstrak: Antioksidan diperlukan untuk menangkal radikal bebas dalam tubuh serta stress oksidatif yang mendorong proses penuaan dan berbagai penyakit degeneratif. Portulaca grandiflora Hook. diketahui memiliki potensi sebagai antioksidan. Perbedaan fungsi organ tanaman menyebabkan perbedaan jalur biosintesis kandungan fitokimia yang terdapat pada tiap organ tanaman. Hal ini dapat mempengaruhi aktivitas antioksidannya. Penelitian ini bertujuan mengukur kandungan total fenolik dan flavonoid pada organ daun, batang tua, batang muda, dan bunga dari tanaman krokot (Portulaca grandiflora Hook.) yang diekstrak menggunakan etanol 96% dan menentukan aktivitas antioksidan dari ekstrak tersebut dengan uji DPPH (2,2-difenil-1-pikrihidrazil). Ekstrak etanol krokot mengandung senyawa fenolik dan flavonoid yang berbeda tiap organ tanaman. Kandungan total fenolik dan flavonoid paling tinggi terdapat pada ekstrak etanol daun krokot yaitu, sebesar 113.26 ± 3.85 mg GAE/g dan 97.99 ± 1.28 mg QE/g. Ekstrak etanol batang tua krokot tergolong antioksidan sedang dengan nilai IC50 122.15 ± 1.30 ppm.
Keyword: Antioksidan, Fenolik, Fenolik, Flavonoid, Portulaca grandiflora Hook

Judul: Kandungan Fitokimia dan Uji Antioksidan Ekstrak Batang Krokot (Portulaca oleracea L.).
Abstrak: Ekstrak batang krokot (Portulaca oleracea L.) telah digunakan secara tradisional dan diduga memiliki potensi sebagai antioksidan alami. Penelitian ini bertujuan membandingkan kandungan senyawa fitokimia batang krokot dengan perbedaan pelarut (akuades, etanol 96%, etil asetat, dan n-heksana) serta membandingkan potensi antioksidan pada uji DPPH. Parameter yang digunakan adalah analisis perbandingan kandungan fitokimia dan persen daya hambat ekstrak terhadap radikal bebas. Metode yang digunakan yaitu ekstraksi maserasi, penentuan kandungan fitokimia, dan pengujian antioksidan DPPH. Hasil pengujian diperoleh kadar air ekstrak batang krokot (Portulaca oleracea L.) sebesar 8.69% dengan rendemen tertinggi pada ekstrak akuades yaitu 9.7%. Hasil uji fitokimia menunjukan bahwa ekstrak batang krokot mengandung senyawa alkaloid, glikosida, dan saponin untuk semua ekstrak. Senyawa fenolik hanya didapat pada ekstrak etil asetat dan etanol 96%. Nilai IC50 batang krokot (Portulaca oleracea L.) pada keempat pelarut tidak dapat ditentukan karena konsentrasi ekstrak dan nilai R kuadrat yang kecil. Ekstrak yang paling baik persen ihibisinya adalah ekstrak etanol 96% dan ekstrak akuades.
Keyword: Batang kroko, persen inhibisi, Portulaca oleracea L., fenolik, fitokimia

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