Judul: Keanekaragaman Jenis Flora di Kawasan Karst Gunung Cibodas, Kecamatan Ciampea, Kabupaten Bogor
Abstrak: Kawasan karst memiliki banyak keunikan, baik dilihat dari bentangan alam maupun biota yang hidup di dalamnya. Wilayah Gunung Cibodas, Kecamatan Ciampea, Kabupaten Bogor, Jawa Barat merupakan salah satu kawasan karst yang terdapat di pulau Jawa, juga memiliki keunikan tersendiri. Namun keberadaan kawasan ini terancam oleh adanya dampak negatif dari berbagai aktivitas manusia di kawasan ini. Untuk mengatasi masalah tersebut diperlukan suatu bentuk pengelolan yang lestari. Perancangan suatu bentuk pengelolaan membutuhkan acuan mengenai kondisi dan potensi sumberdaya kawasan ini. Salah satu acuan tersebut adalah berupa data jenis flora yang ada. Oleh karena itu, diperlukan suatu penelitian untuk mengumpulkan data flora yang hidup dikawasan ini. Tujuan penelitian ini adlah untuk mengetahui keanekaragaman, struktur, serta komposisi jenis flora yang ada di kawasan karst Gunung Cibodas. Hasil penelitian ini diharapkan dapat menjadi petimbangan bagi pengelolaan kawasan karst secara umum serta Gunung Cibodas pada khususnya. Penelitian dilaksanakan di kawasan karst Gunung Cibodas, Kecamatan Ciampea, Kabupaten Bogor yang berada di bawah pengelolaan RPH Gobang BKPH Leuwiliang, KPH Bogor, Perum Perhutani Unit III Jawa Barat dan Banten pada bulan Junu sampai Juli 2006. Bahan dan alat yang digunakan selama penelitian adalah peta lokasi Kabupaten Bogor, peta kerja BKPH Leuwiliang , kompas, tambang/tali rafia, Haga hypsometer, phiband, kamera digital, buku identifikasi jenis tumbuhan, kantong olastik, kertas koran, tali, karton, sasak, alkohol 90% atau spirtus, formulir isian, alat tulis, buu catatan, buku herbarium berupa ranting daun, dan peralatan keperluan herbarium. Jenis data yang dikumpulkan meliputinama jenis, jumlah individu, jumlah jenis, diameter batang, tinggi pohon (tinggi total dan tinggi bebas cabang), serta data penunjang lainnya mengenai kondisi lingkungan.
Keyword: 

Judul: Komposisi Jenis dan Struktur Vegetasi pada Kawasan Karst Gunung Cibodas, Kecamatan Ciampea, Kabupaten Bogor.
Abstrak: Karst area is carbonated rock area that showing karst morphology, with high valued ecosystem of flora and fauna. One of the karst areas in West Java that has quite alarming condition is Gunung Cibodas, Ciampea subdistrict, Bogor regency. The purpose of the research is to analyze the composition and structure of vegetation in the karst area of Gunung Cibodas. The location of observation determined by systematic sampling with random start metode. Analysis vegetation plots are defined based on the direction of the slope and the mouth of the cave. The research found 30 species of seedlings, 32 species of saplings, 2 species of poles, 6 species of trees and 92 species of understorey vegetations. On the direction of the slope and the mouth of the cave is dominated by pioneer species such as Leucaena leucocephala, Calliandra calothyrsus and Macaranga peltata which show the process of secondary succession, moreover the understorey is dominated by the species of Invasive Alien Species (IAS). Stand structure inverted J-shaped curve can only be found on the northern slopes and generally canopy stratification in this karst area consists of three strata, namely stratum C, D and E with the dispersion pattern of this species of dominant groups in the direction of the slope and the mouth of the cave.
Keyword: stand structure, karst vegetation, composition of species

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