Judul: Studi potensi xanton kulit manggis pada berbagai kualitas buah manggis [Gracinia mangostana L.]
Abstrak: Penelitian ini bertujuan untuk mengetahui potensi xanton kulit manggis pada berbagai kualitas buah manggis (Garcinia mangostana L). Penentuan kualitas secara fisik dan penentuan kualitas kimia dilakukan di Laboratorium PKBT (Pusat Kajian Buah-buahan Tropika). Ekstraksi kulit buah buah manggis dilakukan di Laboratorium Ekofisiologi Tanaman, Departemen Agronomi dan Hortikultura (AGH). Sedangkan untuk Evaporasi dilakukan di Laboratorium Umum Hortikultura Departemen AGH. Penentuan kadar xanton dilakukan dengan alat HPLC (High Performance Liquid Chromatography) di Laboratorium terpadu, Faperta, IPB.
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Judul: Akumulasi kadar Xanthone kulit manggis(Garcinia mangostana L.) pada berbagai stadia umur buah dan setelah buah dipanen
Abstrak: Penelitian ini bertujuan untuk mengetahui akumulasi kadar xanthone kulit mugs (Garcinia mangostana L.) selama perkembangan buah dan setelah buah dipanen. Penelitian ini dilaksanakan di Leuwiliang untuk pengambilan sampel, Laboratorium Ekofisiologi Departemen Agronomi dan Hortikultura untuk pengamatan morfologi dan ekstraksi, Laboratorium Hortikultura Departemen Agronomi dan Hortikultura untuk kegiatan evaporasi, sedangkan penentuan kadar xatione dilakukan di Balitro, Cimanggu. Penelitian ini terdiri dari dua penelitian yaitu penelitian akumulasi ampone kulit manggis selama perkembangan buah dan penelitian kadar xanthone kolit manggis setelah buah dipanen. Penelitian pertama terdiri dari empat perlakuan yaitu umur buah 1 bulan setelah anthesis (BSA) (P1), umur buah 2 BSA (2) umur buah 3 BSA (P3) dan umur buah 4 BSA (P4). Penelitian kedua terdiri dari tiga perlakuan yaitu buah tanpa penyimpanan (S0), buah yang disimpan sam 2 minggu setelah panen (MSP) (S2) dan buah yang disimpan selama 4 MSP (S4). Masing-masing perlakuan diulang tiga kali. Selama perkembangan buah mulai umur buah 1 BSA hingga umur buah 4 BSA tidak terdapat perbedaan yang signifikan terhadap akumulasi xanthone pada kulit manggis. Akumulasi xanthone sudah terdapat pada umur buah 1 BSA dengan kadar xanthone sebesar 1.97 g/100 g kulit manggis kering dan akumulasi xanthone tertinggi ditemukan pada umur buah 4 BSA yaitu sebesar 4.78 g/100 g kali manggis kering. Buah manggis setelah dipanen tidak mengalami perubahan kadar xanthone yang signifikan selama penyimpanan. Kadar xanthone tertinggi ditemukan pada penyimpanan 2 MSP yaitu 2.62 g/100 g kulit manggis kering.
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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