Judul: Penggunaan Grafit Mesopori Berlapis Polianilin sebagai Elektroda pada Microbial Fuel Cell.
Abstrak: Microbial fuel cell is a device can generate electricity from organic components through the microbial catabolism. However, the low power density generated in the MFC system is to be one of the main obstacles. The aims study was to determine the excess graphite-coated mesoporous polyaniline as an electrode in the MFC system. This research was conducted by the method of chemical treatment in the formation of mesoporous structure of the graphite surface and electrochemical polymerization potensiostatic in graphite coating with polyaniline. This study resulted in the highest power density were 0.0059 mW.m-2 in the untreated graphite, 0.6 mW.m-2 in mesoporous graphite, 1.895 mW.m-2 in polyaniline coating and 3.557 mW.m-2 in graphite-coated mesoporous polyaniline. The results showed that formation of mesoporouse treatment on the surface of graphite and polyaniline coating on the graphite surface can increase the power density of the MFC system
Keyword: Bogor Agricultural University (IPB), power density, polyaniline, microbial fuel cell, Anode

Judul: Modifikasi Grafit Mesopori dengan Pelapisan Polipirol Sebagai Elektroda pada Microbial Fuel Cell Single Chamber
Abstrak: Microbial Fuel Cell (MFC) is an instrument that utilizes the microbial metabolism in generating electricity. Output of MFC is depend on the electrode that used in capturing the electrons. The treatment given to the graphite electrode are varying the KOH concentration during activation and varying of the applied voltage during electropolymerization. Based on the research, a graphite electrode that activated with the KOH ratio of 1:6 and polypyrrole coated at surface with voltage applied of 0.8 Volts, generates a voltage of 321 mVolts with the electric current of 170.4 μA. The amount of the voltage and electric current affected by the surface area of the electrode and the effect of voltage applied during polypyrrole coating process. Moreover, the microbial metabolism also has some effect on the amount of electricity that obtained.
Keyword: Bogor Agricultural University (IPB), polypyrrole., microbial fuel cell, electropolymerization, Electrical energy

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