Judul: Pembibitan stek daun dan beberapa aspek budidaya teh di perkebunan tugu cimenteng, PT.J.A Wattie sukabumi-jawa barat
Abstrak: Tanaman teh (Camellia sinensis) famili Theaceae me- rupakan tanaman yang berasal dari wilayah sepanjang daerah Asam Burma di bagian barat sampai ke China di bagian timur, dan wilayah Thailand Vietnam di bagian selatan. Wilayah diatas terletak pada batas 25° 35°LU dan 95°-135° garis bujur. Sekarang tanaman teh dibudidayakan secara luas di seluruh bagian dunia, yang tersebar mulai dari Russia 45° LU sampai ke Argentina 27°LS (Darmawidjaya, 1977). Tanaman teh di Indonesia tumbuh baik di daerah dataran rendah dengan ketinggian 400 m diatas permukaan laut, suhu rata-rata 22.8°C; sampai di dataran tinggi ketinggian lebih dari 1550 m diatas permukaan laut, dengan suhu rata- rata 17°C (Adisewojo, 1982). Tanaman ini menghendaki curah hujan merata sepanjang tahun, minimum 2000 mm per tahun dengan kelembaban senantiasa tinggi. Teh yang banyak ditanam di Indonesia termasuk tipe sinensis, assamica dan tipe hybrid, banyak diusahakan secara luas di daerah Jawa Barat, Sumatera Utara, sisanya di Sumatera Barat, Sumatera Selatan, Jawa Tengah dan Jawa Timur.
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Judul: Pengusahaan teh dan peranan beberapa unsur iklim dalam budidaya teh ( Camellia sinensis L. ) di perkebunan Kertamanah PTP XIII Bandung
Abstrak: Tanaman teh (Camellia sinensis L.) merupakan salah sa- tu tanaman komoditi perkebunan yang mempunyai arti ekonomis penting bagi Indonesia, karena merupakan tanaman ekspor yang dapat menambah devisa negara. Sebelum perang dunia kedua tanaman teh di Indonesia mempunyai areal yang relatif sangat luas dibandingkan dengan sekarang, hampir menca- pai 300 000 ha. Juga dalam bidang produksi, nilai nominal ekspor dan persentase ekspor teh Indonesia mencatat rekor yang tinggi. Tetapi ketika Jepang menduduki negeri kita, banyak areal tanaman teh yang diubah secara paksa menjadi areal tanaman pangan sehingga produksi, nilai nominal eks- por dan persentase ekspor teh Indonesia menurun pula. Menurut Schoorel (1974), perkebunan teh di Indonesia dapat dibedakan menjadi tiga golongan berdasarkan ketinggi- annya di atas permukaan laut. Penggolongan tersebut adalah (1) perkebunan daerah rendah, yaitu kebun-kebun yang mem- punyai ketinggian kurang dari 800 m di atas permukaan laut dengan suhu rata-rata 23.9 °C, (2) perkebunan daerah se- dang, yaitu kebun-kebun yang mempunyai ketinggian antara 800 m sampai 1 200 m di atas permukaan laut dengan suhu rata-rata 21.2 °C, dan (3) perkebunan daerah tinggi yaitu kebun-kebun yang mempunyai ketinggian lebih dari 1 200 m di atas permukaan laut dengan suhu rata-rata 19.0 °C. ...
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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