Judul: Evaluasi pengusahaan pabrik minyak kayu putih di Pabrik Sendang Mole, BDH Playen, Gunung Kidul
Abstrak: Pengusahaan tanaman kayu putih (Melaleuca leucaden- dron) pada lahan hutan di Jawa telah dilaksanakan dan berbentuk Kelas Perusahaan Kayu Putih. Penanaman kayu putih di Daerah Istimewa Yogyakarta dilakukan sebagai alternatif untuk menyelamatkan tanah kritis di kawasan hutan di daerah tersebut. Kemudian timbul gagasan untuk mengembangkannya menjadi hutan yang produktif dan mengun- tungkan. Salah satu kegiatan yang dilakukan adalah dengan mendirikan Pabrik Minyak Kayu Putih (PMKP) Sendang Mole, Gunung Kidul. Pengolahan minyak kayu putih di PMKP Sendang Mole menggunakan sistem uap. Dalam satu hari pemasakan selama 24 jam dilakukan empat kali pemasakan. Setiap kali pema- sakan selama 4 jam. Bahan bakar yang digunakan adalah bri- ket daun bekas masakan minyak kayu putih. Tenaga kerja yang digunakan berasal dari penduduk sekitar pabrik, dengan sistem pembayaran borongan. Biaya produksi total pengolahan minyak kayu putih terdiri dari biaya variabel total dan biaya tetap total. Biaya variabel total terdiri dari biaya 1) bahan bakar,...
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Judul: Analisis finansial dan biaya produksi minyak kayu putih (Melaleuca leucadebdron L) di KPH Gunduh
Abstrak: Indonesia merupakan negara yang kaya akan sumberdaya hutan. Berdasarkan Tata Guna Hutan Kesepakatan, luas hutan di Indonesia mencapai 143 juta hektar. Disamping hasil kayu, hasil hutan non kayu juga merupakan potensi yang cukup potensial untuk dipungut hasilnya. Ekspor hasil hutan non kayu telah memberikan sumbangan devisa yang cukup besar. Salah satu hasil hutan non kayu yang banyak dihasilkan oleh Indonesia adalah minyak kayu putih. Pohon kayu putih (Melaleuca leucadendron L) dapat tumbuh di tanah yang kurang subur atau tanah yang tandus (Menon, 1986). Dengan kenyataan di atas, maka industri minyak kayu putih akan mengambil suatu keputusan agar tingkat keun- tungan yang diperoleh dapat setinggi-tingginya. Oleh karena itu perlu ditetapkan harga jual berdasarkan biaya produksinya. Penelitian ini bertujuan untuk menganalisis biaya produksi pengolahan minyak kayu putih, mengetahui luas areal hutan optimum yang dapat mendukung proses produksi serta menilai pengusahaan pabrik minyak kayu putih dari sudut penilaian 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