Judul: Pengamatan Penyakit penting Tanaman Karet (Hevea Muell, Arg.) dI Wilayah Kerja Balai Penyuluhan Pertanian Cikalongkulon Kabupaten Cianjur- Jawa Barat
Abstrak: Survai ini dilakukan di perkebunan karet rakyat desa Mekargalih, desa Cijagang dan desa Majalaya, dengan tujuan untuk menghitung luas serangan patogen yang ada dan intensitas serangan patogen penting pada tanaman karet yang telah menghasilkan lateks (TM) dan pada tanaman karet muda yang belum menghasilkan (TBM). Selain mengamati panyakitnya, juga dilakukan pengamatan sepintas hama yang ada di perkebunan karet rakyat tersebut. Penyakit penting tanaman karet yang terdapat di perkebunan karet rakyat Wilayah Kerja Balai Penyuluhan Pertanian Cikalongkulon ialah gugur daun (Colletotrichum gloeosporioides), embun tepung (Oidium heveae), bercak daun (Cephaleuros sp.), mati pucuk (Botryodiplodia theobromae), mouldy rot (Ceratostomella fimbriata) dan benalu (Loranthus sp.) serta defisiensi kalium. Penyakit-penyakit tersebut dapat mengurangi hasil serta ketahanan pohon karet. Penyakit gugur daun karet yang disebabkan oleh cendawan Colletotrichum gloeosporioides merupakan penyakit yang dominan di perkebunan karet rakyat di daerah ini. Menurut keterangan petugas Dinas Perkebunan setempat, daerah ini merupakan daerah asal eksplosi serangan patogen tersebut.
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Judul: Pengamatan Penyakit Penting Karet (Hevea brasilliensis Muell. Arg.) dan Usaha Pengendaliannya di Perkebunana Ngobo, PTP XVIII (Persero) Semarang-Jawa Tengah
Abstrak: Praktek Lapang ini dilakukan di afdeling Klepu dan Jatirunggo Perkebunan Ngobo, dengan tujuan untuk mengetahui luas dan intensitas serangan penyebab penyakit penting karet di pertanaman tua yang telah menghasilkan lateks (TM) dan di pertanaman muda yang belum menghasilkan (TBM). Selain mengamati penyakitnya, dilakukan juga pengamatan usaha pengendalian penyakit di perkebunan tersebut. Penyakit penting tanaman karet yang terdapat di Perkebunan Ngobo adalah penyakit cendawan akar putih (pada akar), penyakit jamur upas (pada cabang), penyakit mouldx rot penyakit kanker garis dan penyakit kulit dalam coklat - 9 (pada bidang sadap) serta beberapa penyakit daun seperti penyakit gugur daun Cormespora, penyakit bercak daun Qlindrocladium, dan penyakit gugur daun Colleto trichum. Penyakit-penyakit tersebut dapat mengurangi hasil serta ketahanan pohon karet. Terjadinya penyakit penting di Perkebunan Ngobo selalu ada setiap waktu walaupun dalam persentase serangan ringan, kecuali penyakit gugur daun. Corynespora yang merupakan penyakit baru dan menimbulkan masalah yang cukup berarti untuk tahun 1985.
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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