Judul: Tinjauan Agroklimatologi Tanaman Teh di Perkebunan teh Gunung Mas (PTP XII)
Abstrak: Tanaman teh (Camellia sinensis) yang diduga berasal dari pegunungan antara Tibet dar Republik Rakyat Cina sudah mulai dikenal di benua Eropah pada akhir abad 17. Dalam abad ke-18 hasil teh sudah dikenal dan dihargai orang di seluruh dunia, sehingga teh merupakan barang dagangan yang penting dan memberi banyak keuntungan. Dengan demikian negara-negara yang memiliki daerah-daerah dengan syarat tumbuh yang baik bagi tanaman teh, berusaha keras untuk membuka kebun-kebun teh. Negara-negara penghasil teh di dunia adalah India, Sailan, Indonesia, RRC, Jepang, Taiwan, Kenya, Indo Cina, Afrika Selatan, Mozambique, Uganda dan Tanganyika. Di benua Eropa dan Amerika, meskipun banyak memiliki tempat yang memungkinkan penanaman teh, ternyata tidak termasuk negara penghasil teh, karena mahalnya tenaga kerja disana (Adisewojo, 1982). Sebelum perang dunia kedua, Indonesia adalah pengekspor teh ketiga di seluruh dunia, terutama untuk negara-negara di benua Eropa, tetapi semasa perang, banyak kebun-kebun teh rakyat yang rusak atau dibongkar dan diganti tanaman pangan, sehingga produksinya menurun.
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Judul: Pengusahaan tanaman teh di P.T. Perkebunan XII cianten, bogor
Abstrak: Sejarah menyebutkan bahwa Teh (Camellia sinensis) pada mulanya hanya terdapat didataran Asia perbatasan negara negara Muangtai, Burma, India, Laos, Kamboja, dan Cina yang berupa vegetasi hutan liar di wilayah dengan sifat keadaan tanah dan iklim seragam yang baik bagi pertumbuhan teh secara alami. - Cina merupakan negara yang pertama kali mengguna- kan teh sebagai bahan minuman. Buku "Pen Tsao" di ja- man kerajaan Shen Nung pada tahun 2737 SM antara lain telah menulis mengenai teh sebagai hidangan bagi para raja raja di negeri Cina. Pada tahun 780 seorang pe nulis dan ahli tentang teh bernama Lu Yu dalam bukunya yang berjudul "Cha Ching" telah menguraikan mengenai pertanaman teh, cara pemeliharaan, pemetikan daun, pe- ngolahan dan me amu teh sebagai minuman. - Akhir abad keenam teh telah mulai dikenal di ne geri Jepang. Pada tahun 1738 Soichiro Nagatani menemu kan sistim pengolahan teh hijau, dan sejak itu tanaman teh tumbuh dan berkembang dalam suatu areal perkebunan luas. ...
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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