Judul: Kajian Tingkat Pendapatan Petani Sawah Irigasi dengan  Diversifikasi Pola Tanam (Kasus di Kabupaten Karawang,  Jawa Barat)
Abstrak: Kabupaten Karawang memiliki luas 91.090 Ha sawah dan 87% diantaranya merupakan sawah irigasi, yang berarti areal sawah seluas 80.774 ha memperoleh air sepanjang tahun dan seharusnya sepanjang waktu itu pula dapat diusahakan untuk bercocok tanam sehingga Indeks Pertanaman (IP) maksimum (IP 300) dapat tercapai. Hasil kajian di daerah contoh di Desa Citarik, Kecamatan Tirtamulya, Kabupaten Karawang terhadap 20 responden yang mewakili 5 kelompok tani, dalam pemanfaatan sawah garapannya belum maksimum ditunjukkan dari rataan nilai IP yang hanya mencapai 230.
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Judul: Optimasi pola tanam dengan sistem golongan dan kaitannya dengan ketersediaan traktor tangan di Daerah Pengamat Karawang, Daerah Irigasi Tarum Utara, Kabupaten Karawang, Propinsi Jawa Barat
Abstrak: Pertanian tidak bisa dipisahkan dari bangsa Indonesia karena merupakan salah satu sektor penting. Banyak usaha yang dilakukan untuk meningkatkan dan mempertahankan produksi pertanian diantaranya peningkatan penggunaan air irigasi. Dalam bidang pertanian, penghematan air dapat dilakukan dengan mengubah sistem penyaluran, sistem pemberian air dan didukung oleh pemilihan jenis tanaman, masa tanam, serta manajemen yang tepat. Salah satu kebijakan yang dilakukan di dalam pengaturan pemberian air irigasi dengan sistem golongan. Areal yang terdapat dalam satu golongan yang sama, yang mencakup ribuan atau puluhan ribu hektar, akan memperoleh jatah air sama dalam jangka waktu yang sama. Kalau kegiatan komponen produksi sudah beralih ke kegiatan berikutnya maka jatah air dan jangka waktunya akan berubah. Hal inilah yang sering mengakibatkan keterlambatan tanam, kekurangan air, atau pemanfaatan lahan dan sistem irigasi kurang efektif karená masalah kekurangan alat-alat dan mesin-mesin pertanian, misalnya traktor tangan. ...
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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