Judul: Pengukuran kadar CO2 udara di dalam tegakan beberapa jenis hutan tanaman di Cikole dan Ciwidey, Jawa Barat
Abstrak: Karbondioksida (CO₂), merupakan salah satu gas rumah kaca yang emisinya ke udara paling tinggi. Lima puluh lima persen (55%) dari kontribusi gas rumah kaca terdiri dari CO2, sisanya terdiri dari 17 persen CFC 11 dan CFC 12, 15 persen metan, 7 persen CFC lainnya dan 6 persen nitrous oksida. Oleh sebab itu CO₂ dianggap sebagai penyumbang terbesar dalam pemanasan global (Houghton et al., 1990). Ogawa (1990) melaporkan bahwa konsentrasi CO2 selama 250 tahun belakangan ini (sejak tahun 1740) naik dari 280 ppm menjadi 350 ppm, dan diperkirakan apabila 100 tahun mendatang (sekitar tahun 2090) terjadi kenaikan konsentrasi CO2 menjadi dua kali akan mengakibatkan terjadinya perubahan iklim dunia, serta akan mengakibatkan peningkatan suhu permukaan bumi rata-rata antara 3-5,5 °C. Salah satu akibat yang dapat ditimbulkan oleh kenaikan suhu bumi yaitu akan menyebabkan mencairnya sebahagian dari es abadi yang terdapat di daerah Antartika dan Artatika, sehingga akan menambah volume air laut. Kenaikan permukaan air laut diperkirakan sekitar 50-80 cm. Indonesia sebagai negara kepulauan akan sangat merasakan akibatnya…dst
Keyword: CO2, Pinus merkusi, Agathis lorantifaku

Judul: Daya Rosot Beberapa Jenis Pohon Perkotaan terhadap Karbondioksida (CO2) (Studi Kasus di Jalur Hijau Jalan Raya Pajajaran-Bogor)
Abstrak: The global warming happens due to high concentration of certain gasses in the air which are called Green Houses Gasses (GHGs). The global warming is mostly caused by human activities and industries. Carbon dioxide (CO2) is the most important anthropogenic GHGs which caused a variety of activities in both cities moving or not moving as households, hotels, industries, motor vehicles and other activities require driving and heating energy partly derived from the combustion of fossil fuels such as diesel, kerosene and coal. Increased levels of CO2 in the urban air can be overcome with the forest one city. The increment of CO2 concentration in the city can be decreased by implementing urban trees. Carbon dioxide will be absorbed and converted into oxygen through photosynthesis process. The selection of urban trees is needed in order to decrease CO2 effectively. Therefore the study on carbon dioxide sink ability of urban plants should be conducted. The CO2 sink ability of urban trees was measured using carbohydrate method. The carbon dioxide mass was obtained by converting the carbohydrate mass produced from photosynthesis. Other data that were collected consisted of total and width of leaves. More leaves per tree have higher ability of carbon dioxide sink. Wider leaf has higher ability of carbon dioxide sink too. The ability of CO2 sinks from nine species of urban trees is stated in cm2 of leaf width per hour (g CO2/cm2/hour). The result shows that the ability of C. manghas is 8,391 x 10-4; A. mangium is 3,430 x 10-4; S. macrophylla is 2,547 x 10-4; B. purpurea is 2,056 x 10-4; M. calabura is 1,843 x 10-4; F. elastica is 1,466 x 10-4; F. benjamina is 0,787 x 10-4; P. indicus is 0,630 x 10-4; and S. mahagoni is 0,499 x 10-4. It can be concluded that C. manghas, F. elastica and S. macrophylla are the most effective in sinking the CO2.
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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