Judul: Sebaran Penyakit Akar Putih (Rigidoporus microporus (Swatz) Van Ov ) Pada Tanaman Teh (Camellia sznenszs (L ) O. Kuntze ) di Lapang dan Eksplorasi Beberapa Cendawan Antagonis
Abstrak: Penelitian ini terbagi dalam dua kegiatan penelitian yaitu penelitian di lapang yang diiakukan di perkebunan teh PTP Nusantara VIII Gunung Mas, Cisarua, Bogor, Jawa Barat clan di labomtorium Mikologi Jurusan Hama dan Penyakit Tumbuhan, bstitut Pertanian Bogor Penelitian di lapang meliputi wawancara pengamatan keadaan kebun, sebaran tanaman sakit, gejala kerusakan tanaman sakit dan hubungan antara kerusakan tanaman dengan beberapa faktor lingkungan. Penelitian di laboratorium meliputi isolasi cendawan patogen, isolasi mikroba tanah, uji antagonisme invitro dan uji antagonis invivo.
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Judul: Eksplorasi dan Identifikasi Cendawan Antagonis terhadap Rigidoporus lignosus Penyebab Jamur Akar Putih pada Karet
Abstrak: Industri karet berperan dalam peningkatan pendapatan petani, masyarakat, dan negara, juga dalam pembuatan produk, serta peranan terhadap pelestarian lingkungan. Salah satu hambatan dalam pengembangan budidaya karet adalah adanya penyakit jamur akar putih yang disebabkan oleh Rigidoporus lignosus. Penelitian ini bertujuan mengeksplorasi dan mengidentifikasi cendawan antagonis terhadap R. lignosus. Penelitian dilakukan dengan mengambil contoh tanah dari tanaman karet dan kelapa sawit untuk dibuat suspensi. Suspensi dibuat seri pengenceran hingga tingkat pengenceran 10-5, masing-masing seri pengenceran tersebut diambil sebanyak 1 ml suspensi dan dibiakkan pada media potato dextrose agar (PDA). Uji antagonisme in vitro antara agens antagonis dengan R. lignosus dilakukan dengan menggunakan metode dual culture. Pengamatan dilakukan dengan mengukur jari-jari koloni patogen yang menjauhi isolat cendawan kandidat dan jari-jari koloni patogen yang mendekati isolat cendawan kandidat, serta menghitung penghambatan kandidat agens antagonis. Identifikasi menggunakan compound microscope. Dari hasil isolasi cendawan rhizosfer diperoleh 26 isolat kandidat antagonis, 10 isolat diantaranya memiliki kemampuan antagonisme terhadap patogen R. lignosus. Hasil identifikasi menunjukkan sebanyak tiga isolat adalah Trichoderma harzianum, enam isolat adalah Gliocladium virens, dan satu isolat adalah Penicillium resticulosum. Mekanisme antagonis yang dilakukan oleh T. harzianum dan G. virens adalah hiperparasit, antibiosis, lisis, dan kompetisi ruang. Sedangkan untuk P. resticulosum adalah kompetisi ruang.
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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