Judul: Analisis Finansial Usaha Agroforestry Kemenyan di Desa Parbubu II Kabupaten Tapanuli Utara
Abstrak: Getah kemenyan sebagai hasil hutan bukan kayu memiliki nilai ekonomi yang tiggi dan digunakan sebagai kosmetik, pengawet, acara keagamaan, parfum, dan industri rokok. Pemanfaatan hutan kemenyan merupakan mata pencaharian yang sudah dilakukan secara sederhana dan turun menurun. Hal ini menjadi sumber pendapatan asli daerah. Penelitian dilakukan di Desa Parbubu II Tapanuli Utara Provinsi Sumatera Utara Maret sampai Mei 2019. Tujuan dari penelitian ini adalah menganalisis kelayakan finansial usaha kemenyan dan menguji sensitivitas dari penurunan harga dan kenaikan biaya terhadap keuntungan usaha, serta mengetahui tingkat pendapatan rumah tangga petani hutan. Analisis finansial dilakukan menggunakan metode Discounted Cash Flow dengan nilai NPV Rp264.680.107, BCR sebesar 57,8, dan IRR sebesar 105%. Usaha lebih sensitif terhadap adanya penurunan harga. Sebesar 83,33% tergolong sejahtera dan sebesar 16,66% responden termasuk dalam kategori pra sejahtera.
Keyword: analisis finansial, analisis sensitivitas, hasil hutan bukan kayu, hutan kemenyan

Judul: Analisis Finansial Usaha Hutan Rakyat di Desa Karyasari, Kecamatan Leuwiliang, Kabupaten Bogor
Abstrak: Potensi kayu dan non kayu dari hutan rakyat dapat dijadikan sebagai alternatif pemenuhan kebutuhan bahan baku, meningkatkan kesejahteraan dan pendapatan bagi rumah tangga petani hutan dengan memanfaatkan lahan milik sebagai bentuk investasi yang dapat memberikan kontribusi dan keuntungan bagi petani hutan rakyat. Tujuan dari penelitian ini memberikan informasi kelayakan usaha hutan rakyat di Desa Karyasari secara finansial dan sensitivitas usaha terhadap berbagai kemungkinan yang terjadi. Berdasarkan hasil analisis finansial usaha hutan rakyat dengan pola monokultur dan agroforestri secara finansial layak dikembangkan melalui tiga indikator kelayakan yakni NPV, B/C Ratio dan IRR. Dari hasil tersebut usaha hutan rakyat dengan pola agroforestri jati, kayu afrika dan tujuh tanaman pengisi lebih menguntungkan untuk diusahakan dibandingkan dengan pola agroforestri mahoni, mangium dan enam tanaman pengisi dan pola monokultur mangium dengan nilai NPV sebesar Rp 3.301.356.466, B/C Ratio sebesar 4,41 dan IRR sebesar 25%. Usaha hutan rakyat di Desa Karyasari lebih sensitif terhadap penurunan harga jual dibandingkan dengan kenaikan biaya produksi.
Keyword: agroforestri, analisis finansial, Desa Karyasari, hutan rakyat

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