Judul: Pengaruh atmosfer pada musim hujan dan musim kemarau terhadap penyiraman pancaran surya di desa Cikarawang
Abstrak: Energi surya adalah sumber utama dari energi atmos- fer. Penyebarannya di seluruh permukaan bumi pengendali dari cuaca dan iklim. Energi surya merupakan merupakan penyebab pokok dari semua perubahan dan gerak di dalam atmosfer. 4 Keterbatasan energi surya di daerah tropik sering juga menjadi kendala dalam produksi padi, khususnya yang ditanam pada musim hujan. Produksi padi, jagung, kacang- kacangan dan sorgum semakin meningkat dengan meningkatnya kerapatan limpahan pancaran surya. Suatu penelitian telah dilakukan untuk mengetahui perbedaan (penyirnaan) pancaran tingkat pancaran baur, tingkat pancaran surya oleh atmosfer dan surya yang mencapai permukaan bumi hujan dan musim kemarau. attenuasi komposisi pada musim Penelitian ini menggunakan data sekunder dari data penelitian Dr. Ir. M. Blantran de Rozari, pada bulan Juli 1987 sampai Pebruari 1988, di Desa Cikarawang Sindangbarang Kabupaten Bogor. Kecamatan ...
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Judul: Hubungan intersepsi dan absorbsi radiasi surya dengan biomas, dan produksi pertanaman tumpang sari pada arah baris berbeda
Abstrak: Tujuan penelitian ini ialah untuk mengetahui (1) Intersepsi dan Absorbsi radiasi surya pada pertanaman tumpang sari jagung dan kedelai dengan arah baris berbeda, (2) hubungan intersepsi dan absorbsi radiasi surya dengan biomas dan (3) produksi pertanaman tumpang sari jagung dan kedelai pada arah baris berbeda. Penelitian dilakukan di kebun percobaan Stasiun Klimatologi, Badan Meteorologi dan Geofisika di Cikarawang yang berlangsung mulai tanggal 16 5 Maret 1989. Juli 9 Oktober 1988 dan 1 Desember 1988 Tanaman yang digunakan sebagai tumpang sari adalah jagung (Zea mays L.) dan kedelai (Glycine max L.), dengan jarak tanam jagung (200x40) cm dan kedelai (50x15) cm. Rancangan percobaan yang digunakan ialah rancangan acak lengkap yang disusun secara faktorial, dengan 2 perlakuan yaitu arah baris (Utara-Selatan dan Timur-Barat) dan waktu tanam. - Metoda pengamtan meliputi pengamatan klimatologis dan pengamatan agronomis. Pengamatan klimatologis yang dilak- ukan adalah : radiasi datang di atas tajuk jagung, di atas tajuk kedelai dan di permukaan tanah, albedo dan radiasi ...
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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