Judul: Peningkatan Keawetan Kayu Bintangur (Calophyllum sp.) dalam Rangka Konservasi Bangunan Rumah Tradisional Huma Hai
Abstrak: Keawetan kayu Bintangur (Calophyllum sp.) sebagai bahan konstruksi rumah tradisional Huma Hai belum banyak dilaporkan, padahal informasi tersebut sangat penting untuk mendukung pemanfaatannya secara efektif dan berkelanjutan. Suatu penelitian laboratoris telah dilakukan untuk mengetahui ketahanan kayu Bintangur terhadap serangan rayap kayu kering Cryptotermes cynocephalus Light dan jamur pelapuk Schizophyllum commune Fr, sebelum dan setelah proses pengawetan dengan bahan pengawet berbahan aktif copper, chrome dan boron, CCB (7.5% dan 10% w/v) serta thiocyanomethylthio benzothiazole, TCMTB (2.5% dan 5% w/v). Kedua jenis bahan pengawet tersebut diaplikasikan melalui metode rendaman dingin dan rendaman panas dingin. Pengujian ketahanan terhadap kedua organisme perusak kayu tersebut dilakukan berdasarkan SNI 01.7207-2006. Hasil penelitian menunjukkan bahwa aplikasi bahan pengawet CCB dan TCMTB masing-masing meningkatkan ketahanan kayu Bintangur terhadap rayap kayu kering C. cynocephalus dan jamur pelapuk S. commune dari Kelas 1V (tidak tahan) menjadi Kelas II (tahan).
Keyword: bintangur, CCB, keawetan, TCMTB

Judul: Manfaat ekonomi pengawetan kayu bahan bangunan perumahan
Abstrak: Jenis kayu yang awet secara alami hanya 15-20% dari 4.000 jenis kayu yang terdapat di Indonesia. Jenis kayu yang mempunyai keawetan alami rendah akan mudah terserang rayap sehingga umur pakainya relatif rendah. Untuk meningkatkan umur pakai kayu berkeawetan rendah perlu dilakukan pengawetan kayu. Penelitian ini bertujuan untuk memberikan gambaran manfaat ekonomi pengawetan kayu yang ditinjau melalui perhitungan biaya tahunan serta nilai kerusakan kayu bahan bangunan tersebut. Penelitian ini dilakukan pada perumahan yang diawetkan yaitu Perumahan Perum Perumnas Bantarjati dan perumahan yang tidak diawetkan yaitu Perumahan BTN Cimanggu Permai. Komponen kayu yang diamati yaitu kusen pintu, kusen jendela, rangka plafon, lisplang, kuda-kuda, plafon dan daun pintu. Kerusakan komponen kayu akibat serangan faktor perusak kayu digunakan untuk menghitung kerugian komponen tersebut. Berdasarkan jenis komponennya, serangan yang terbesar ditemukan pada kusen pintu dan kusen jendela. Tingkat kerusakan yang terbesar ditimbulkan oleh Rayap Tanah (Coptotermes curvignatus).
Keyword: pengawetan kayu

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