Judul: Erapan fosfat, kelarutan hara makro dan mikro serta pengaruh besi terhadap padi sawah
Abstrak: Penggenangan lahan sebagai sawah bukaan baru akan menyebabkan berlangsungnya serangkaian proses fisiko-kimia dan biokimia yang akan mempengaruhi tanaman padi. Perubahan akibat penggenangan diantaranya penurunan potensial redoks, kenaikan atau penurunan pH, kenaikan daya hantar listrik, hilangnya nitrat, akumulasi amonia, terbentuknya asam-asam organik, kenaikan kelarutan ion fero, mangan, fosfat dan silika dan pelepasan kation ke dalam larutan tanah. Potensial redoks (Eh) dan pH tanah merupakan dua faktor utama dan saling berkaitan dalam mempengaruhi kelarutan dan ketersediaan hara serta transformasinya didalam tanah.
Keyword: Fosfat, pH tanah, Potensial redoks

Judul: Pengaruh Trass dan Pupuk Fosfor terhadap Produksi Padi serta Perubahan Sifat Kimia Tanah Sawah
Abstrak: Indonesia adalah salah satu negara yang mengkonsumsi beras tertinggi di dunia. Lahan sawah sebagai sumber utama penghasil beras saat ini semakin berkurang akibat konversi lahan pertanian ke non pertanian. Banyak unsur hara dari dalam tanah sawah yang keluar melalui panen, salah satunya adalah Si.Trass adalah salah satu bahan yang mengandung banyak silika sehingga berpotensi sebagai bahan yang dapat meningkatkan silika di dalam tanah. Percobaan dalam rancangan Acak Lengkap Faktoral dua faktor telah dilakukan dengan faktor pertama adalah Trass/Trass Bakar sebagai sumber Si dan faktor kedua adalah pupuk P dengan sumber SP36. Trass/Trass Bakar diberikan dalam 3 taraf yaitu tanpa Trass/Trass Bakar, 1.25% bobot tanah (90 g/pot) dan 2.5% bobot tanah (180 g/pot) dengan pot berberat 7 kg tanah BKM. Fosfor diberikan dalam 3 taraf yaitu tanpa P, 0,45 g/pot dan 0,9 g/pot dalam bentuk SP36. Hasil penelitian menunjukkan bahwa perlakuan Trass dan Trass Bakar serta pemberian pupuk P dengan SP36 nyata meningkatkan tinggi tanaman, jumlah anakan dan bobot gabah. Serapan Si padi tergantung pada sumber Si yang ditambahkan. Penambahan Si ke dalam tanah meningkatkan serapan P diduga, akibat peningkatan ketersediaan P.
Keyword: Trass, fosfor, silikon, padi

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