Judul: Kajian pengaruh hidrolisis asam terhadap karakteristik gula palma cair
Abstrak: Sugar is one of Indonesian main comodity even in the household and industry. In 2004, national demand of sugar reached 3.4 million tons whereas domestic sugar production just recovered 60% from the demand. Utilization of nan-cane sugar resources from palm planation is one solution to overcome the lack of sugar.
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Judul: Analisis efisiensi proses produksi untuk peningkatan kinerja industri gula tebu (Cane Sugar) (Studi kasus di PG. Jatiluhur Majalengka, Jawa Barat)
Abstrak: Sugar is one of the most important commodities in Indonesia. Most of sugar manufacturing in Indonesia was owned or sun by Indonesian government. Sugar consumption rate cannot be fulfilled by local sugar manufacturer, that's why importing sugar became an option. The insignificant rate of increasing of sugar production every year make import rate is keep increasing Efficiency in sugar production process is one thing that need some attention. This time, most of sugar factory that owned by government are decreasing in productivity. PG Jatitujuh is sugar processing factory that processing cane into white crystal sugar (SHS) and one of sugar factory in Java that still runs well. Efficiency in sugar production process can be analyzed by using PG Jatitujuh production data. Analysis result shows that efficiency in sugar production process can be rendered, by optimalised increasing of imbibitions water. The optimum value of imbibitions water is 25-30 percent of processed cane. The decline of pol value in the amount of 0,01 percent is equal with 1,729 ton or equal with Rp. 8.297.865,- recovery sugar £rom bagasse. The decline of HK value in the amount of 0,01 percent is equal with 0,273 ton or equal with Rp. 1.3 12.524,- recovery sugar from molasses.
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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