Judul: Studi peranan lingkungan (sifat kimia dan fisika tanah serta cuaca) terhadap cemaran getah kuning buah manggis (Garcinia mangostana)
Abstrak: Yellow sap contamination is a major problem caused the poor quality of mangosteen fruits for export. The research aimed to study (1) variability of yellow sap contamination in some mangosteen production centers (2) variability of soil chemical properties and their effects on the yellow sap contamination, (3) the variability of soil physical properties and their effects on the yellow sap contamination, (4) variability of rainfall as controlling water balance and its relationship with the yellow sap contamination of the mangosteen fruit. The study was conducted at 10 mangosteen production centers, namely Karacak and Barengkok (Bogor, West Java), Garogek and Pusaka Mulya (Purwakarta, West Java), Koto Lua, Baringin, Pakandangan, Padang Laweh, and Lalan (West Sumatra), and Sukarame (Lampung).
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Judul: Pengaruh iklim mikro terhadap kejadian getah kuning buah Manggis (Garcinia mangostana L.)
Abstrak: Tantangan agribisnis manggis di Indonesia adalah produktivitas yang relatif rendah serta kualitas yang belum memenuhi standar. Faktor yang dominan mempengaruhi kualitas buah manggis adalah masalah fisiologis yang disebut getah kuning yang ditunjukkan oleh adanya getah kuning pada permukaan luar buah atau di dalam buah. Gangguan getah kuning pada aril manggis seringkali tidak dapat dibedakan dari buah yang sehat. Hal ini mengakibatkan kehilangan yang signifikan terhadap kualitas dan kepercayaan pasar terhadap buah ini. Getah kuning merupakan permasalahan fisiologis yang terkait dengan faktor ekologis. Permasalahan yang dihadapi, dari beragam faktor lingkungan (ekologis) yang mempengaruhi terjadinya getah kuning (fisiologis), faktor lingkungan manakah yang lebih dominan berpengaruh terhadap terjadinya getah kuning. Penelitian ini bertujuan untuk mengetahui faktor-faktor lingkungan yang berpengaruh terhadap terjadinya masalah fisiologis getah kuning serta kualitas buah manggis, dari dua lokasi produksi manggis yaitu di kampung Cengal dan Jamblang, desa Karacak, kecamatan Leuwiliang, kabupaten Bogor, provinsi Jawa Barat.
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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