Judul: Efikasi fire safe 108-wood sebagai bahan penghambat api (Fire retardant)
Abstrak: Pemberian bahan penghambat api (fire retardant) pada kayu dimaksudkan untuk meningkatkan sifat tahan panas, menghambat penguraian kayu oleh panas, dan menghambat laju perambatan api bila terjadi kebakaran sehingga tindakan pengendaliannya lebih dimungkinkan. Suatu penelitian telah dilakukan untuk mengetahui efikasi (keampuhan) Fire Safe 108 Wood sebagai bahan penghambat api serta pengaruhnya terhadap kadar air, keteguhan tekan sejajar serat, kekerasan, dan keteguhan lentur kayu meranti (Shorea sp). Pengujian dilakukan secara laboratoris di Pusat Penelitian dan Pengembangan Pemukiman, Departemen Pekerjaan Umum, Bandung dengan menggunakan alat Tabung Pembakar Model CS 5.
Keyword: Bahan penghambat api, Fire retardant, Fire safe 108-wood

Judul: Studi pengaruh penambahan bahan penghambat api flame out terhadap sifat fisis, mekanis dan ketahanan api kayu lapis struktural
Abstrak: Kayu lapis yang digunakan sebagai bahan bangunan dinamakan kayu lapis struktural. Salah satu kelemahan bahan bangunan ini terhadap faktor non biologis adalah mudah terbakar oleh api. Salah satu usaha untuk meningkatkan ketahanan kayu lapis struktural terhadap api adalah melapisinya dengan bahan penghambat api. Penggunaan kayu lapis struktural sebagai bahan konstruksi disyaratkan harus mampu menahan beban yang direncanakan. Apabila kayu lapis struktural terbakar maka kekuatan fisis maupun mekanisnya akan menurun. Oleh karena itu perlu suatu studi tentang pengaruh pemberian bahan penghambat api terhadap sifat fisis, mekanis dan ketahanan api kayu lapis struktural. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan bahan penghambat api dan tebal kayu lapis struktural terhadap sifat fisis, mekanis dan sifat ketahanan api. Penelitian ini dilakukan di Laboratorium Bahan Komposit, Pusat Penelitian dan Pengembangan Fisika Terapan, Lembaga Ilmu Pengetahuan Indonesia Pusat Penelitian Ilmu Pengetahuan dan Teknologi Serpong Jawa Barat.
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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