Judul: Karakteristik Kulit Ceker Ayam yang Disamak dengan Kombinasi Krom dan Mimosa serta Ekstrak Daun Teh (Camelia sinensis).
Abstrak: Skin tanning is process of converting rawhide skin protein into skin tanned by tanning materials, that result a change in the physical properties of unstable to stable and resistant to environmental influences such as physical pressure, weather, and microorganisms. Waste from tanning process is solid waste, gas, and liquid. For not polluting the environment, liquid waste containing chromium (0.7%) should be processed in the mix with natural tanning materials, like tea. This research used the skin of chicken claw that used combination of tanning (chemical tanning and tea extract) with different concentrations of chrome and nature tanning materials (mimosa and tea extracts) (70:20:10), (60:20:20) and (50:20:30), respectively. Parameters in this reseacrh was the quality of the skin tensile test, elongation test and skin rips test. The best concentration of tea extract for physical characteristics of the tanned chicken claw leather is addition of tea extract 10% intensile test, 20% tea extract in elongation test and 30% tea extract in skin rips test.
Keyword: Bogor Agricultural University (IPB), tea, tanning, eather

Judul: Karakteristik Kulit Ceker Ayam yang Disamak dengan Kombinasi Krom dan Mimosa serta Ekstrak Daun Jambu Biji (Psidium guajava Linn.)
Abstrak: Tanning is the process of converting protein rawhide into leather which stable and not easily decompose. Tanning can be performed on the skin of chicken claw because it has a protein content that is not different from the protein skin of cattle about 23%. The use of chromium can be overcome with vegetable tanning materials that derived from plants and environmentally friendly. The purpose of this study was to determine the characteristics of the tanned skin of chicken claw with a combination of chrome, mimosa and guava leaf extract. Observed variables consisted of tensile strength, elongation, and tear endurance with repetition performed 3 times. The results showed that the concentration of guava leaf extract different effect on tensile strength, but has no effect on elongation and tear endurance of leather. Chrome and mimosa still give effect to the tanning process, but the addition of guava leaf extract as much as 10% showed optimum ability to help increase the tensile endurance of leather.
Keyword: tanning, Bogor Agricultural University (IPB), guava leaf, chicken claw

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