Judul: Pemanfaatan Ampas Teh dari Industri Teh Botol sebagai Bahan Baku Pembuatan papan Partikel
Abstrak: Industri minuman teh botol berkenbang sangat pesat di Indonesia. Jumlah produksi teh botol di Indonesia pada tahun 1989 tercatat 88 047 000 liter dengan nilai penjualan Rp 25 069 775 000 (BPS, 1991). Meskipun industri ini berkembanq pesat namun menghadapi masalah dengan limbahnya yang berupa ampas teh. Dalam rangka mewujudkan industri yang berwawasan lingkungan maka perlu dilakukan penelitian terhadap ampas teh tersebut.
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Judul: Kajian peluang pendirian industri papan partikel berdasarkan potensi bahan baku ampas tebu di daerah Cirebon, Jawa Barat
Abstrak: Ampas tebu dihasilkan dari pengolahan gula dengan proses ekstrak nira di pabrik gula. Proses pengolahan ini menghasilkan ampas sebanyak 35 40 persen dari bobot tebu. Pemanfaatan ampas tebu semula hanya sebagai bahan bakar dalam industri yang bersangkutan. Tetapi manfaatnya sebagai bahan bakar masih menghasilkan sisa ampas yang cukup banyak, yang memerlukan penanganan dalam pembuang- annya. Dengan teknologi proses dikembangkan pemanfaatan ampas tebu sebagai bahan baku papan partikel yang bernilai ekonomi tinggi. Tujuan penelitian ini adalah menganalisis peluang investasi pendirian industri papan partikel dari ampas tebu sebagai langkah awal untuk melakukan kajian kelayakan in- dustri. Ruang lingkup pengkajian meliputi analisis secara umum terhadap aspek pasar, bahan baku, teknis teknologis, manajemen operasi dan keuangan proyek. Metode yang digunakan adalah metode kuadrat terkecil untuk analisis pasar, metode pemulusan eksponensial untuk analisis ketersediaan bahan baku, metode perbandingan eksponensial untuk analisis lokasi dan analisis PBP, IRR dan kepekaan untuk analisis keuangan proyek. ...
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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