Judul: Mempelajari kantong air (reservoir) untuk tujuan irigasi di Perkebunan Gedeh
Abstrak: Air merupakan salah satu unsur hara yang penting bagi tanaman. Kebutuhan air berbeda-beda untuk setiap tanaman, waktu dan tempat. Tanaman teh memerlukan syarat tumbuh dan air yang relatif tinggi dibandingkan tanaman keras lainnya sehingga biasanya tanaman teh ditanam pada daerah pegunungan. Pada beberapa perkebunan teh, ketersediaan air pada setiap waktu berfluktuasi banyaknya, sehingga hal ini menjadi salah satu faktor yang menjadikan rendah dan berfluktuasinya produksi teh. Penelitian ini bertujuan untuk mempelajari sistem irigasi, dan kelayakan pembuatan kantong air (reservoir), yang meliputi penentuan alat, jadwal, dan jumlah air irigasi, serta volume & tempat yang ideal dari kantong air (reservoir) di perkebunan teh. Kantong air (reservoir) diharapkan dapat menyuplai air untuk kebutuhan tanaman dan pemeliharaan tanaman serta menyimpan kelebihan air. Penelitian ini juga bertujuan untuk menyarankan beberapa alternatif irigasi yang sesuai dengan perkebunan teh, berdasarkan ketersediaan air yang sesungguhnya. Penelitian dilakukan di Perkebunan Gedeh, Cugenang, Cianjur, Jawa Barat. Penelitian dimulai dengan pengukuran topografi, pengukuran sifat fisik tanah, seperti infiltasi, dan tekstur tanah. Pengambilan data sifat-sifat tanaman teh dan data analisis kelayakan dilakukan dengan studi pustaka dan survey lapangan untuk mendapatkan hasil yang aktual. ...
Keyword: 

Judul: Mempelajari Neraca Air Tanah Harian untuk Estimasi Besarnya ETc dan Kc Tanaman Teh di PTPN VII Perkebunan Gunung Mas Puncak, Jawa Barat
Abstrak: Didalam proses pertanian, air merupakan salah satu faktor terpenting. Kebutuhan air bagi tanaman sebagian besar dari air tanah yang diserap akar tanaman dan ditranspirasikan melalui daun (Suseno, 1974). Banyaknya air yang diperlukan tanaman tergantung antara lain pada jenis tanaman, fase pertumbuhan dan evapotranspirasi yang ada hubungannya dengan faktor lingkungan seperti iklim, kesuburan tanah dan kelembaban tanah (Richards dan Wedleich, 1952). Hubungan antara kandungan air tanah dan pertumbuhan tanaman antara lain dapat dikemukakan bahwa pertumbuhan tanaman dapat dipengaruhi oleh bertambahnya kekeringan setelah kapasitas lapang. Pada lapisan tanah atas kandungan air tanah akan berkurang karena evaporasi dan transpirasi yang sangat dipengaruhi oleh unsur-unsur klimatologi, jenis tanah dan kedalaman tanah.
Keyword: 

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