Judul: Penataan Sistem Pemangkasan Tanaman Teh Studi Kasus di Perkebunan Gunung Mas PT Perkebunan XII, Cisarua, Jawa Barat
Abstrak: Pemangkasan tanaman teh merupakan mlah satu bentuk pemeliharaan tananan teh di kebun,yang antara lain berguna untuk memudakan kembali ranting dan batang-batang pohon. Pemangkasan terhadap tanaman dilakukan rutin setiap sekitar 3-4 tahun. Iklim dan curah hujan serta pemupukan dan pemherantasa hama penyakit menimbulkan fluktuasi yang besar pada produksi pucuk teh di kebun. Fluktuasi yang besar berdampak timbulnya kesulitan manajerial, seperti ddlam memgatur jumlah tenaga kerja, jam kerja pabrik, penggudangan, dan lain-lain.
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Judul: Penataan sistem Pemangkasan Tanaman Teh Studi Kasus di Perkebunan Gunung Mas PT Perkebunan XII, Cisarua Jawa Barat
Abstrak: Pemangkasan tanaman teh merupakan salah satu bentuk pemeliharaan tanaman teh di kebun yang antara lain berguna untuk memudakan kembali ranting dan batang-batang pohon. Pemangkasan terhadap tanaman dilakukan rutin setiap seki tar 3- 4 tahun. Iklim dan curah hujan serta pemupukan dan pemberantasan hama penyakit menimbulkan fluktuasi yang besar pada produksi pucuk teh di kebun. Fluktuasi yang besar berdampak timbulnya kesulitan manajerial, seperti dalam memgatur jumlah tenaga kerja, jam kerja pabrik, penggudangan, dan lain-lain. Penataan sistem pemangkasan memiliki potensi untuk diarahkan mengatasi persoalan besarnya flukutuasi produksi teh di kebun ini. Pada setiap pohon yang dipangkas, menyebabkan pohon tersebut tidak berproduksi. Penelitian ini dimaksudkan untuk dua tujuan, pertama, penataan pemangkasan untuk dapat mengurangi fluktuasi produksi di kebun, dan kedua, pemangkasan diatur agar kehilangan produksi akibat pemangkasan diusahakan sesedikit mungkin. Penelitian dilakukan dengan mengambil data sekunder di Perkebunan Gunung Mas PT Perkebunan XII, Cisarua, Jawa Barat dan berlangsung dari bulan Agustus sampai bulan Oktober 1987. Program dinamik membantu memecahkan masalah kapan (bulan apa) sebaiknya pemangkasan dilakukan dan be rapa jumlah pohon yang dipangkasnya. Hasil penelitian ini berupa rangkaian daftar jumlah tanaman yang dipangkas pada setiap bulan: Untuk Perkebu nan Gunung Mas, tempat penelitian ini berlangsung, disaran- kan pemangkasan dilakukan pada bulan Mei, Juni dan Juli dengan jumlah pangkasan masing-masing sebanyak 1.5, 8 dan 6 pohon untuk setiap 100 pohon yang ada di kebun….
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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