Judul: Biolistrik Limbah Cair Perikanan dengan Microbial Fuel Cell Menggunakan Jarak Elektroda Tembaga yang Berbeda
Abstrak: Microbial fuel cell (MFC) adalah reaktor bioelectrochemical yang dapat mengkonversi energi kimia dari zat organik pada air limbah menjadi listrik. Penelitian ini bertujuan untuk mengetahui kemampuan limbah cair perikanan sebagai penghasil listrik melalui MFC satu bejana, serta jarak elektroda tembaga yang optimal untuk menghasilkan energi listrik dalam sistem MFC dengan penambahan lumpur aktif. Sistem MFC yang digunakan yaitu MFC satu bejana dengan perlakuan jarak elektroda yang diberikan sebesar 2 cm, 4 cm, dan 6 cm. Jarak elektroda tidak memberikan pengaruh terhadap penurunan beban polutan limbah, namun memberikan pengaruh terhadap elektrisitas yang dihasilkan. Hasil penelitian ini menunjukkan sistem MFC mampu menurunkan rata-rata nilai BOD sebesar 50,78% dan COD sebesar 33,29%, serta mampu meningkatkan rata-rata nilai TAN sebesar 62,41%, MLSS sebesar 26,39%, dan MLVSS sebesar 88,53%. Perlakuan elektroda tembaga dengan jarak 4 cm menunjukkan nilai elektrisitas yang lebih optimal dengan rata-rata nilai elektrisitas 0,366±0,092 V.
Keyword: jarak elektroda, lumpur aktif, microbial fuel cell, tembaga

Judul: Kinerja Microbial Fuel Cell Pembangkit Biolistrik dengan Variasi Rasio Luas Elektroda dan Volume Limbah Cair Perikanan.
Abstrak: Limbah cair perikanan dapat menyebabkan pencemaran lingkungan jika tidak dikelola dengan baik. Pengolahan limbah cair perikanan secara konvensional memerlukan biaya dan energi yang cukup tinggi. Microbial fuel cell (MFC) dapat membangkitkan energi listrik dari penguraian bahan organik pada limbah dengan memanfaatkan mikroorganisme. Penelitian dilakukan menggunakan MFC satu bejana dengan rasio luas elektroda dan volume limbah cair perikanan yang berbeda yaitu 1:80 cm2/cm3, 1:40 cm2/cm3 dan 1:8 cm2/cm3. Tegangan listrik tertinggi terdapat pada perlakuan rasio 1:80 cm2/cm3 sebesar 428.98 mV. Arus listrik tertinggi terdapat pada perlakuan 1:40 cm2/cm3 sebesar 3.26 mA. Rapat daya listrik tertinggi terdapat pada perlakuan 1:40 cm2/cm3 sebesar 1 185.87 mW/m2. Nilai chemical oxygen demand (COD) mengalami penurunan sebesar 62% pada perlakuan rasio 1:8 cm2/cm3 dan biochemical oxygen demand (BOD) mengalami penurunan sebesar 42% pada perlakuan rasio 1:80 cm2/cm3. Nilai mixed liquor suspended solids (MLSS) dan mixed liquor volatile suspended solids (MLVSS) mengalami peningkatan sebesar 1 471% dan 1 725% pada perlakuan rasio 1:40 cm2/cm3. Nilai pH mengalami meningkat menjadi 7.5-8.4. Nilai total amonia nitrogen (TAN) mengalami penurunan sebesar 89-93%.
Keyword: limbah cair perikanan, listrik, luas elektroda, microbial fuel cell

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