Judul: Aktivitas antioksidan serta korelasinya dengan kadar fenol, flavonoid, dan antosianin total pada enam spesies Rhododendron
Abstrak: Rhododendron diketahui bermanfaat bagi kesehatan, salah satunya sebagai antioksidan. Tumbuhan Rhododendron asal Indonesia yang digunakan pada penelitian ini terdiri atas R. javanicum, R. retusum, R. malayanum, R. konori, R. seranicum, dan R. jasminiflorum. Aktivitas antioksidan ditentukan menggunakan metode 2,2-difenil-1-pikrilhidrazil (DPPH), ferric reducing antioxidant power (FRAP), dan cupric ion reducing antioxidant capacity (CUPRAC). Hasilnya menunjukkan metode yang digunakan menghasilkan nilai kapasitas antioksidan yang berbeda nyata secara analisis ragam. Bagian batang R. retusum memiliki kapasitas antioksidan tertinggi, yaitu 36.68 µmol troloks/g serbuk kering dengan menggunakan metode DPPH. R. konori bagian daun memiliki aktivitas antioksidan tertingi, yakni 941.76 dan 1793.62 µmol troloks/g serbuk kering masing-masing dengan menggunakan metode FRAP dan CUPRAC. Kadar fenol total berkorelasi signifikan dengan aktivitas antioksidan sedangkan kadar flavonoid dan antosianin total memiliki korelasi yang tidak signifikan.
Keyword: antioxidant activity, Rhododendron, total anthocyanin, total flavonoid,

Judul: Klt Autografi Dpph Dan Kc-Sm Untuk Deteksi Dan Identifikasi Senyawa Antioksidan Dari 6 Spesies Rhododendron
Abstrak: Rhododendron merupakan genus tumbuhan berbunga dari suku Ericaceae yang memiliki aktivitas hayati, salah satunya sebagai antioksidan. Dalam penelitian ini, senyawa antioksidan dari ekstrak daun dan batang 6 spesies Rhododendron dideteksi menggunakan kromatografi lapis tipis dipadukan dengan autografi 2,2-difenil-1-pikrilhidrazil (DPPH) dengan eluen kloroform-diklorometana-metanol (8.4:1:0.6 v/v/v). Ekstrak daun R. malayanum memiliki aktivitas antioksidan tertinggi. Isolasi senyawa antioksidan dari daun R. malayanum menggunakan kromatografi lapis tipis preparatif menghasilkan isolat yang memiliki ativitas antioksidan tertinggi, yaitu isolat F4 dan F7. Isolat diidentifikasi dengan kromatografi cair-spektrometer massa (KC-SM). Hasil identifikasi dengan KC-SM menunjukkan bahwa isolat F4 pada Rt 11.01 diduga merupakan senyawa golongan flavonol dengan bobot molekul (BM) 506 g/mol. Isolat F7 pada Rt 12.11 diduga merupakan senyawa asam hidroksisinamat dengan BM 530 g/mol dan fraksi F7 pada Rt 14.04 diduga senyawa resveratrol dengan BM 390 g/mol.
Keyword: DPPH, KC-SM, KLT autografi, Rhododendron, antioksidan

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