Judul: Inventarisasi Hama Dan Penyakit Jati Emas (Tectona grandis Lf.) Di Ma'had Al Zaytun, Indramayu, Jawa Barat
Abstrak: Indonesia memiliki 4000 jenis kayu yang terdiri dari 786 genus dan 106 famili, 400 jenis di antaranya cukup representatif dan berpoteasi. Satu di antara jenis kayu tersebut adalah kayu jati yang memiliki nilai ekonomi tinggi, kayunya awet, kuat, dan mudah dikerjakan, serta serbaguna. Daur hidup jati sangat panjang yang dapat dipanen jika telah berumur lebih dari 30 tahun.
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Judul: Perhitungan nilai tegakan hutan jati (Tectona grandis L.f.) di Jawa
Abstrak: Kayu jati (Tectona grandis L. f.) adalah jenis kayu yang banyak digunakan oleh masyarakat Indonesia, terutama di Jawa, untuk berbagai kegunaan seperti bantalan kereta api, meubelair, venir, flooring, konstruksi ringan dan berat, barang kerajinan, kayu bakar dan sebagainya. Untuk itu supaya didapatkan hasil yang optimal harus dilakukan pengelolaan dengan sungguh-sungguh agar diperoleh tegakan akhir yang berkualitas tinggi dan menghasilkan keuntungan finansial yang setinggi mungkin. Dalam hal ini pengelola hutan perlu mengetahui berapa nilai dari tegakan tersebut. Tujuan yang ingin dicapai dalam penelitian ini adalah untuk mengetahui nilai tegakan hutan Kelas Perusahaan (KP) Jati di Jawa yang dikelola Perum: Perhutani. Perhitungan yang digunakan dalam penelitian ini adalah dengan pendekatan harga jual untuk masing-masing jenis sortimen (A-I, A-II, dan A-III) dan kayu bakar jati yang dihasilkan dari masing-masing Kelas Umur (KU) KP Jati. Dalam hal ini dibuat asumsi bahwa setiap KU dalam KP Jati akan menghasilkan kayu bulat jati dan kayu bakar jati sesuai dengan ukuran diameternya.....
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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