Judul: Potensi Biomassa dan Karbon pada Tegakan Eucalyptus pellita di PT. Musi Hutan Persada Kabupaten Muara Enim
Abstrak: Hutan memiliki peran besar sebagai penyedia jasa lingkungan dalam kaitannya dengan perubahan iklim dan pemanasan global. Hutan memiliki kemampuan sebagai penyerap, penyimpan sekaligus menjadi sumber emisi karbon. Tujuan penelitian ini adalah untuk mengetahui besarnya kandungan biomassa dan karbon yang tersimpan pada tegakan hutan tanaman Eucalyptus pellita dan mengetahui potensi tegakan hutan tanaman Eucalyptus pellita dalam menyerap karbon dioksida (CO2) berdasarkan kelas umurnya. Metode sampling yang digunakan adalah systematic sampling with random start. Hasil penelitian ini menunjukkan bahwa besarnya kandungan biomassa pohon berkisar 35.97-284.75 ton/ha dan karbon pohonnya berkisar antara 16.19-128.14 ton C/ha, serta potensi menyerap gas CO2 dari amosfer bekisar 59.41-470.26 ton/ha.
Keyword: biomassa, CO2, Eucalyptus pellita, hutan tanaman, karbon

Judul: Potensi Pemanfaatan Limbah Eucalyptus pellita Sebagai Bahan Baku Energi Biomassa di PT. Musi Hutan Persada
Abstrak: Limbah pemanenan adalah bagian pohon yang tidak dimanfaatkan oleh pola pemanfaatan yang berlaku dan dibiarkan di dalam hutan. Penelitian ini bertujuan menghitung potensi limbah Eucalyptus pellita di PT. Musi Hutan Persada serta menguji kadar proksimat dari empat jenis limbah kayu sebagai bahan baku energi biomassa. Pengukuran potensi limbah dilakukan pada kegiatan penebangan dan TPn. Potensi biomassa limbah pada PT. MHP didapatkan sebesar 98,31 ton/ha. Penggunaan alat tebang dan kemampuan operator mempengaruhi besarnya potensi limbah. Metode pengujian mengacu pada standar ASTM, SNI, dan TAPPI. Hasil analisis proksimat menunjukkan tiga jenis limbah kayu yang diuji memiliki nilai kadar air 9,11-12,31%, kadar zat terbang 76,71-84,44%, kadar abu 1,43-3,22%, kadar karbon terikat 14,14-20,07%, dan nilai kalor 4.113-4.186 kkal/kg. Limbah kayu Eucalyptus pellita memiliki kualitas baik sebagai sumber energi biomassa dengan kemampuan limbah ranting sebesar 184,66 kkal/ha, limbah kulit sebesar 89,79 kkal/ha dan limbah batang sebesar 86,31 kkal/ha.
Keyword: analisis proksimat, biomassa, Eucalyptus pellita, limbah, nilai kalor

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