Judul: Karakterisasi Sifat Reologi Gula Merah Aren Cair pada Berbagai pH dan Konsentrasi.
Abstrak: Proses produksi gula merah masih dilakukan secara tradisional dan dalam skala kecil sehingga sangat memengaruhi kualitas gula merah. Nira yang merupakan bahan baku gula merah rentan kerusakan akibat proses fermentasi. Proses fermentasi nira ditunjukkan dengan menurunnya nilai pH. Nira yang telah terfermentasi menghasilkan gula merah dengan kualitas rendah yaitu gula merah yang tidak dapat mengeras atau masih bersifat cair. Penelitian ini akan mengkarakterisasi sifat reologi pada gula merah cair yang dihasilkan dari nira yang telah terfermentasi. Penelitian dilakukan dalam dua tahap yaitu tahap persiapan dan tahap karakterisasi. Tahap persiapan meliputi pembuatan gula merah pada 5 taraf pH dalam rentang 3.0-6.5 dan 4 taraf konsentrasi (tingkat evaporasi). Tahap karakterisasi dilakukan dengan mengukur reologi menggunakan Anton paar MCR Physica 301 dengan shear rate sweep mode pada 1-10000/s. Selain itu, dilakukan analisis kimia berupa pH, kadar air, dan total gula. Hasil penelitian menunjukkan bahwa semakin lama penyimpanan nira akan menghasilkan gula merah yang tidak dapat mengeras dengan pH semakin rendah, total gula semakin rendah dan kadar air semakin tinggi. Semakin lama pemasakan akan menghasilkan gula merah aren cair dengan kadar air semakin rendah dan total gula semakin tinggi. Gula merah aren cair menunjukkan sifat non-Newtonian dengan tipe pseudoplastik dengan kecenderungan semakin rendah pH maka sifat pseudoplastik semakin nyata. Sifat pseudoplastik pada gula merah dapat dipengaruhi oleh kandungan metabolit hasil fermentasi antara lain gula pereduksi, dekstran, etanol, asam asetat dan komponen yang terbentuk selama pemasakan seperti melanoidin.
Keyword: nira, gula merah, pH, pseudoplastik, reologi

Judul: Mempelajari Faktor-Faktor yang Mempengaruhi Kelunakan Gula Merah dari Nira Kelapa Kasus di Daerah Cianjur
Abstrak: Penelitian dilakukan meliputi enam tahap yaitu penelitian dilapangan, tentang macam-macam cara penaganan dan mutu gula merah di lapangan, percobaan pengaruh tingkat pemasakan, percobaan penambahan minyak dan pati, percobaan penundaan nira, dan hubungan antara warna dan kekerasan gula merah. Percobaan perlakuan dengan berbagai tingkat pemasakan (dengan lama pemasakan berbeda 5 menit) menunjukkan bahwa semakin lama pemasakan dilakukan, gula merah yang dihasilkan semakin keras. Perbedaan kekerasan diduga disebabkan oleh semakin rendahnya kadar air produk akibat penguapan yang terjadi selama pemasakan. Dari percobaan ini juga terlihat bahwa semakin lama pemasakan, gula merah yang dihasilkan cenderung semakin gelap.
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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