Judul: Pengaruh pemberian bio-organik terhadap penampilan media tumbuh tanaman reklamasi di PT. Koba Tin, Kec. Koba, Kab Bangka, Propinsi Bangka
Abstrak: Indonesia terkenal sebagai negara yang kaya akan sumberdaya alamnya, baik yang dapat diperbaharui maupun yang tidak dapat diperbaharui. Salah satu jenis sumberdaya alam yang tidak dapat diperbaharui adalah mineral logam yaitu timah. Permasalahan yang timbul akibat proses pertambangan ini adalah kerusakan bentang alam yang disebabkan oleh pembukaan lahan untuk areal tambang, pengelolaan tambang dan juga pembuangan limbah dari proses pemisahan bijih tambang (tailing). Salah satu upaya untuk mengurangi dampak negatif tersebut, PT. Koba Tin telah melakukan kegiatan penutupan media bekas tambang dalam rangka perbaikan sifat fisik, kimia dan biologiknya dengan menggunakan bio-organik yang dapat membantu dalam hal tersebut. Hasil penelitian menunjukkan pemberian bio-organik pada media tumbuh sand tailing secara umum dapat membantu memperbaiki sifat fisik (kesarangan), sifat kimia (status unsur hara dan kesuburan) dan sifat biologik (persentase infeksi cendawan dan jumlah jenis binatang tanah). Pemberian cendawan endomikoriza dan asam humat (M1.HM) dapat menurunkan kesarangan media. Pada status kesuburan media, pencampuran tailing dengan top soil dapat menaikkan kandungan bahan organik hingga mencapai 1%, ketersediaan unsur makro N (0,06%). P (75,1 ppm) dan kejenuhan basa (100%). Pencampuran tailing dengan top soil dan pemberian cendawan endomikoriza (M1.TS) meningkatkan ketersediaan unsur K (29,5 ppm), jumlah kation Ca (1,36 me/100 g), Mg (0,74 me/100 g) dan K (0,06 me/100 g). Pencampuran dengan top soil dan diberi asam humat (MO.HMTS) menaikkan jumlah kation Na (0,08 me/100g). Pemberian cendawan endomikoriza dan asam humat (M1.HM) meningkatkan KTK (3,55 me/100g) dan dapat menurunkan kandungan...
Keyword: bio-organik, Media tumbuh

Judul: Pengaruh Pemberian Bahan Organik dan Polimer Alam Serta Sintetik terhadap Beberapa Sifat Fisik dan Kimia Tanah Tailing Tambang 25 Wilasi Pangkalpinang Unit Penambangan Timah Bangka (UPTB)
Abstrak: Kegiatan penambangan yang tidak menyertakan tindakan reklamasi/rehabilitasi dapat merusak sifat-sifat tanah serta keseimbangan ekologis (fisik, biotis dan sosial) daerah sekitarnya. Maka diperlukan adanya suatu tindakan untuk mempercepat pulihnya kondisi lahan bekas penambangan. Penelitian ini bertujuan untuk mempelajari pengaruh pemberian bahan organik (kotoran sapi) dan polimer (latex, Polyacrylamide (PAM) dan kimia Polyvinylalcohol (PVA) terhadap beberapa sifat fisik dan kimia tanah tailing tambang 25 Wilasi Pangkalpinang UPTB, Pulau Bangka.
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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